# Building a 120mm rotary table



## arnoldb

While building Elmer's Grasshopper, I saw that I could really do with an RT for my mill. I'm still broke from buying the mill, and an RT is pretty expensive here in Namibia.

Some research turned up bits and pieces of information on RTs, and then I hit gold on Dean's build of his rotary table - excellently detailed as always by Dean - and the plans available there. Thank you both Dean and Steve :bow: 

My build is based on Dean's, but I'm adapting some dimensions and methods to the materials and tools I have available, as well as changing some bits to suit my own needs.
Some of the things I want from the RT are:
1. Use as much material as possible from what I have on hand or can economically obtain
2. An adapter to take any of my Myford chucks and to do machining securely on it.
3. Adjustment of backlash on the worm drive - and full disengagement of the drive for "quick indexing"
4. Accuracy to 0.1 degrees or better from the hand wheel, with an option to add dividing plates as needed.
5. Compatibility with as much of my existing tooling as I have.

As I have to make the worm and gear, I decided on a 72 tooth gear; that gives 5 degrees per turn of the hand wheel and should make things easy to use. 

For the last couple of weeks, I've sourced and scrounged whatever materials I would need for the build; some I had lying around, and a lot I had to buy. I ended up with: Some bits of 10x60mm flat bar and a bit of 12mm plate for the base, a lump of cast iron for the table, phosphor bronze to make the gear out of, an old bit of bolt for some material to make diverse bits, aluminium for the handwheel, a brand new angular contact bearing, a bit of shaft from a printer with 2 small bearings to salvage for mounting the hand wheel shaft, and some 8mm and 16mm silver steel to make the shaft, worm and gear cutter from:






I started on the base; the bit of 12mm plate I had was too big, so I sawed it down in the bandsaw. It was a bit too big for the bandsaw as well; so I started with as much as possible of the plate clamped in the saw vise:





Then, when the saw frame bottomed on the plate, I flipped the plate around with less clamped to finish the last bit :





The last cut was done in one go, and I ended up with the RT base plate and some left-over bits of 12mm thick plate for other projects:





Then I clamped the plate to the mill table with some bits from the clamping kit and supported on two identical bearing outer rings as spacers, and milled three of the four sides square, with the two opposing sides I could get to, to the exact width for the plate (140mm):





The last side of the plate was done by adding an additional small clamp on the opposite completed side to keep the plate in position, and then moving the main clamps over to the finished side as well to clamp down properly to mill the last side both square and to dimension.

Fortunately, I could chuck the plate in the 4-jaw on my lathe; this makes it easy to face and bore the hole for the bearing. The corners barely clear the bed while swinging in the head-gap. :




To prevent the corners of the plate from hitting the apron while feeding, I just used the top slide to offset the toolbit enough. The cross slide is pretty close to maximum extension as well!

With the old Myford in medium back gear speed, I started the biggest facing cut I have tried to date. It took a while; very slow infeed at the start with interrupted cuts, and looking at the chips coming off to increase feed rate towards the center. Not a pretty picture, but the "ringy bands" looks worse than they are actually:




 :-[ - I think some of those "bands" was caused by lighting a cigarette or two during the facing process 

Next I center drilled, the plate, and drilled an 8mm hole through it with the lathe running at its second highest speed, followed by a 19mm drill (the biggest I have) in high back gear speed:





Then I bored the hole bigger; (from 19mm to 61.97 mm) I started with a cheapy tungsten carbide tipped boring bar and 20 thou (~0.5mm) depths of cut and things went OK until I tried some bigger cuts. At 40 thou cuts things were going well, but then the carbide tip splintered and everything ground to a halt. Not feeling in the mood to try and re-sharpen the tool, and with the hole big enough for my favourite HSS left-hand turning tool bit to have adequate clearance, I just plonked that in and finished the cut. I intentionally left a 0.5mm thick ridge about 2mm wide at the back.That is to allow the bearing I have to be pre-loaded without the center of it actually rising up and touching the bottom of the table later on :




A test with the bearing showed that the hole is just about the right size for a press fit for the bearing, but with the plate a bit warm from machining, and the bearing cold, I decided to let everything cool down to the same temperature overnight to make sure of the final fit for the bearing.

Regards, Arnold


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## zeeprogrammer

Nice project Arnold.
This will be interesting (no surprise there).


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## Deanofid

Oh, neat Arnold. This will be a good thread.

I've had a lot of people write me about this, and some ask about backlash take up. The only thing I came up with was eccentrics for the bearing cages on the worm shaft. I'll be interested to see how you do it.

Good luck with this new project. It'll sure be worth it in the end.

Dean


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## ksouers

Good one, Arnold. Count me in ;D


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## RobWilson

Good start Arnold Thm:

going to be an interesting build 

Regards Rob


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## Hamstn

I to have read and downloaded the drawing in the link. I have started to gather the parts and actually started the the table with a 25lb cast iron weight. Mine will be 9".

So with that i will be following with great interest.


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## arnoldb

Thank you Carl - well, double thank you for your confidence! - I hope it's interesting, or at least informative in some fashion.

Dean, thank you. My first thoughts were also eccentrics, but that adds a kind of a "fiddly" factor to keep in place and mount and line up with the gear wheel . I'm going for a slot in the front of the table with a block that guides in it with a pivot block at the back into which the shaft bearings are mounted. At the back a similar pivot block but with a bush to give the shaft travel when adjusting. Not an entirely clear description - I know, and maybe a wacky layout - but I think it will work in the end. I received a quote this week from someone who I respect very much: "If you don't try it, you will never know if it would have worked." - So, I'm into a bit of trying ;D

Thank you Kevin ;D
Rob, Thanks mate ;D ... stickpoke :big: (inside joke ;D)

Hamstn, thank you. That's a nice big RT you are building then Thm: - remember we like pictures on HMEM  You might have to adapt some things for your own build though; you'll need a much stronger base for a start. And please don't take anything I do here as gospel; I 'm pretty much a newbie (and hard-headed at that), so some of the things I do or methods I use might not be entirely appropriate. Fortunately, there are a lot of skilled members here on HMEM, and I'm sure they will supply good pointers where/when it is needed.

Today was a bit slow; I didn't get as far as I wanted to, but some progress is better than none.

First thing, I picked up with the bearing fit, and as I thought, it needed some final sizing. With all the bits at the same temperature, the fit for the bearing would have been too tight, and I ended up taking another 0.02mm (a 0.01mm cut) out of the plate. Then the bearing was a nice hand press fit part-way into it's hole; the rest will need a bit of tapping with a hammer:





Then I flipped the plate in the chuck - just loosened two adjacent jaws of the chuck, flipped, and tightened down the same jaws, making sure the plate was flush on the chuck teeth with no swarf trapped. There was no need to perfectly re-center it - the last facing is just to get rid of the scale and to make sure the top face is completely parallel with the bottom. As the table will be riding on this surface, I tried to get a better finish - and succeeded:




After getting rid of the scale off the plate, I stopped and honed the cutting bit to get it really nice and sharp, thus the better result. The scale on HRS plate really blunts a HSS cutting bit quickly.

Next, some bits sawn from 60x10mm flat bar to make the sides of the base:





I just clamped the whole lot together in the mill vise and flycut the sides flat. A milling cutter might have been quicker, but once again, the scale on the plates would have made it blunt in short order. I can (and did - twice) re-sharpen the HSS bit I have in the flycutter. I also pushed things a bit hard; you can see the blue chips that came off; had me doing a dance while feeding getting hit by those :big: and a couple of times I saw sparks flying when some bit of "unknown" matter in the scale was encountered:





Then with both the longer pieces one-at-a-time, I squared the bandsawed ends down; one end just square, and then moved to the other end and squared , and then down to the 140mm length needed. After initially squaring the second end, I just measured how far it must be machined down (both plates were about 4mm too long at that point) and went down in 1mm steps on the mill hand wheels with the last step the required fraction of a mm on the hand wheel:




That 17mm end mill makes big chips on 1mm cuts and a vigorous feed ;D

End of work today; the top plate of the base finished, and the "long" parts of the base down to size:




The short sides still need to be machined to length. Most of the side plates also need some slot milling in them.
I've not made a final decision on whether to bolt everything together, or to weld it together. I'm thinking of welding the side-plates together, and bolting the top plate to them to prevent distortion on the top plate...

Regards, Arnold


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## Deanofid

Coming along well, Arnold. HRS isn't a lot of fun on a small machine, but we know it can be done up nice, eh? Thumbs up, buddy.
I think you have a good idea to weld up the sides then screw mount them to the top piece. The heat will surely take it out of square, but you can true it up before screwing down the top.

I hope you don't mind if I comment to Hamstn in your thread, since it looks like he's reading it.




			
				Hamstn  said:
			
		

> I to have read and downloaded the drawing in the link.



Hamstn, please have a good look at the prints before you start, in case I've included any goofs!
(And thanks for checking out the article.)

Dean


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## zeeprogrammer

I really appreciate the detail in your posts...for example...talking about the blue chips (and the dancing) and resharpening. It means a lot to me (and I'm sure other newbies) who wonder, not just if they're doing things right, but if others have the same experience.

It's a big reason why I like this forum...so many members do the same.

I have to admit...I'm hoping for bolting because welding is way beyond my current ability. ;D But do it the way you need to...I suspect welding removes the worry of things coming loose.


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## SBWHART

Great thread Arnold 

That will be one handy bit of kit when done

Stew


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## lordedmond

be carful of that bearing in the fourth pic , i know its a sealed bearing but you never know


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## arnoldb

Thanks Dean - The old HRS can be a bit taxing; one day I want to get my grubby paws on some decent steel & see what the difference is. Most likely won't be able to machine it though :big:. Thanks - It'll be welded sides and bolted top then ;D And No - I don't mind any comments in the thread to others; "We" are all in this together 

Carl, thank you. Remember, I'm a newbie as well ;D. I don't normally push my machines hard enough to make blue chips though. I like good clean chips coming off - I might be wrong, but for me it shows I have the right feed and speed going. The blue chips in this case was from pushing things to get trough the scale crust the HRS have - it blunts HSS cutters very quickly. As to welding vs bolts - I'm going with my own gut feel, but this job should work well just bolted together as well. The welding saves me from drilling and tapping holes and counterboring for screws and so on. The end result might be stronger as well. The downside, as I have mentioned, is that welding (stick welding in this case) cause things to warp. And the welds can look like chicken es-eightsh-eye-tee if I do it :big:

Thank you Stew - I can't wait to try it out! - A long way to go still though.

lordedmond, thanks for checking in, and welcome to HMEM. We're a pretty inquisitive crowd  - It would be nice if you post an intro in the welcome thread. And no worries about that bearing - it's a bust one waiting to be disassembled into bits to act as parallels 

I had a bit of time in the shop after work... A bit disappointing at times, but not too bad.

I milled both the "short" sides of the base square and to length. As I'd decided on welding the lower part of the base, I thought it prudent to mil the clamp-down slots in these as well, before welding things together. For milling the 10mm slots, I marked and drilled 8mm holes at the ends:




While locating the holes, I set the mill's x-axis stops, which I have not used thus far, to stop on the holes - so I could do incremental cuts and just stop at the ends without looking at the hand wheels. Disappointment; I have not looked closely at the stops supplied with the mill, and thought they were steel, but it turned out it was plastic looking (and feeling!) like steel. Found that out when tightening the first one down; It went kgrrk and cracked on me. Another mill mod chalked up!

I bought a new 10mm HSS slot mill on Saturday, and set about using it to mill the slots between the holes:




On the first slot, things didn't go entirely to plan though... The milling bit easily chewed out the slot with 2.5mm down feeds on each pass. Then I got greedy; and tried a 3.5mm down feed... No problem for the cutter; it worked happily, but left a much rougher finish on the sides of the slot - that seemed to get worse as I went... 
By the other end of the slot, I could visibly see the slot was a LOT (~1mm) wider than at the start. I did lock the y-axis on the mill, but it shifted. Note to self! - lock down harder and don't get greedy. I ended up with an 11mm slot and rough edges. I smoothed both sides of the slot out with some fine milling cuts to look OK - with a very fine climb-milling pass (0.1mm) on each side - fortunately the clamp-down slots are not crucial in size.
The slot on the other piece went much better; I wasn't greedy. I'll have an RT with one wider mounting slot. I could have milled the second slot to match the first one, but I'll leave it as is - as a permanent reminder not to be greedy in future ;D 
And another thing, from now on, if I want a slot of "x mm" size, I'll make it with a cutter of "x-1 mm" size and have some clean-up room left!

The plates with the slots - with the over-large one on the right-hand:





Mock-up of base - some welding required  :





Regards, Arnold


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## wizardofwood

Hi Arnold
Nice work so far, I enjoy seeing the mods/improvements you have been making to your machines.
On your last pic I noticed the thread table underneath has British cycle thread on it. Just wondering where you got that table as it looks useful
Cheers
Byrne


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## ariz

Arnold the RT is going to go well, nice work till now!

on the greedy subject  ... these milling machine are the culprit!
I broke a 16 mm mill after 5 minutes that I have had the new machine: to try it I started on a piece of alu with a cut of 1 mm, then 2 mm, 3 mm, 4 mm, 5 mm... crack
and sometimes I make the same errors also now: the man IS greedy :big: and these (relatively big) machines are a temptation :big:


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## arnoldb

Thank you Byrne . Yes, the table you saw is part of a larger sheet (A3 size) that I leave below my glass "surface plate". It has tables on it with thread specifications and drill sizes for a lot of the different thread types (Metric, BSW, UN, BA, BSC etc) and is a reduced version of a sheet that Somta (a South African company that makes milling & drilling bits etc) issued at one time. I wish I can get my hands on an original sheet to hang on the wall! It is indeed very handy; it allows me to look at different treading requirements and translate to the closest metric equivalents which I primarily work with. I can't share a full copy of the sheet, as I think it may be copyrighted, but it is easy to build up something similar for personal use from information off web sites ;D

Ariz, thank you ;D - I'm happy to know I'm not the only one getting greedy then :big: Fortunately I've not broken any cutters on the mill yet - now I just jinxed myself ;D

Well, no more progress on the rotary table, but another arrival in my shop this evening:





It's a "Standard" - that's the make - power hacksaw that a friend is leaving with me for long term storage... I can use it as I see fit ;D
It needs some cleaning, and TLC in general, but appears to be in pretty good shape below all the gunk. The only major problem I can see after a cursory inspection is that it's coolant pump is completely frozen up; I hope I can repair that.

If anybody has any information on this machine, I'd really appreciate it. I know GIYF, but a search on "Standard Hacksaw" returns an overload of information on "standard hacksaw" and very little on "Standard Hacksaw" - So far, Ive only been able to establish that the "Standard Hacksaw Ltd" was taken over by Spear & Jackson Inc in 1970 - which makes this saw British and most likely built before 1970 ?

Its a HEAVY bugger - must weigh in at somewhere around 100kg - and it does not look that heavy. I had to provide my friend with copious amounts of beer to recuperate after we unloaded it! I think some more beers at a later stage might make him consider selling it to me ;D - or at least forget that he left it here :big:

Regards, Arnold


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## Philjoe5

This seems like a very ambitious project to me and I'm just getting up to speed on your progress. Sure looks great so far. The flycutting operation on multiple pieces of stock held in the vise caught my attention. When I've tried doing this with an end mill and a depth of cut in the neighborhood of 0.020", invariably one of those pieces will slip on me. I have an inexpensive Chinese made milling vise and wonder if that's the problem ??? Or can you get away with this in a flycutting operation because of the lighter cut ???

Anyway thanks for posting this project.

Cheers,
Phil


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## New_Guy

nice hacksaw you just cant beat them for cutting all sorts of stuff 

really enjoying the build Thm:


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## arnoldb

Phil, New_Guy, thank you for having a look and your comments .

Phil, yes, maybe it is a bit ambitious, but I like pushing my skills to the limit and a little beyond; that's the only way to learn. So far things have been fairly common machining operations. Saying that, a year ago I couldn't even turn a good press fit for a bearing, so the "common" is used loosely ;D - things just become easier as one goes along. 
The flat bar I'm using is fairly rough on the surface - that helped with clamping them together. If it was smoother and I thought the pieces might slip, I would just have put some strips of paper between them. I also have an inexpensive Chinese vise - but I made some changes to it to function a bit better; added shim plates to prevent the movable jaw lifting as much as it used to, and also cleaned up the screw in the lathe with a file to make it smoother in operation - this makes it easier to really tighten workpieces up. 
I think the flycutter might make a tiny bit of a difference, but not really much. And I was pushing my flycutter really hard; 0.5mm depths of cut - which is pretty close to your 0.020" - and BIG cuts for a flycutter. Like I said, whenever I could detect the cutting bit in it getting dull, I'd stop after that pass and re-sharpen it. Much cheaper than stuffing up end mills :big: - just takes a bit longer to machine.

I welded up the base frame after work today.

First I clamped the bits of the frame together on the bottom of the base top where it would mount. I did this to make sure that the clamping didn't push things out of kilter, and it also allowed me to make final adjustments with a small hammer to get everything lined up as close as possible:





Then very carefully shifted the clamped assembly over onto a spare piece of plate to make sure nothing shifted, and put the whole lot down in an open space on the workshop floor for welding together. (I have a steel workbench for this kind of thing, but it is too cluttered right now :-[):





Four good tack-welds with the stick welder mid-way on the inside of each corner to prevent distortion as much as possible, and then a lot of welding followed. All welded up on the inside corners:





Not a pretty sight :hDe:; I only had 2.5mm welding rods on hand, which were a bit small for this job, and the thick metal seemed to conduct a lot of heat away very quickly while welding, so my little AC welder struggled a bit even on it's maximum current setting. One day, I'll get myself a bigger DC inverter welder (or a MIG ;D):




 :hDe: To be honest... My welding skills suck and need improvement.

Regards, Arnold


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## Maryak

Arnold,

It's coming together nicely. :bow:

For a corner fillet weld such as those, it may help if you grind off half of each corner on the slotted plates giving a 45 deg V. This will help to ensure the weld gets good penetration and strength at the same time as allowing you to retain the original edges for alignment.

Looks to me like you are using a 240V single phase welder. In Oz I would use a Satin craft 13 electrode as these have a slower flux than a Satin craft 12. This helps stop the flux from running into the weld pool and stopping the arc. My welder has only 2 settings 2.5 and 3.2 mm so I try and use the shortest possible cable between the power point and the welder. If I have to go longer a heavier duty cable helps keep up the volts and amps.

Best Regards
Bob


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## PhillyVa

Arnold, Bob,

You can preheat the parts with a propane torch _(the kind you would use for plumbing)_ or something like that along with a bevel to get better flow of the welding rod.

Regards

Philly


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## Hamstn

Pre heating would help. Without looking I don't know what 2.5 converts to but running smaller rod on thick piece like that should still weld just fine and even a bit smoother then shown. In this case the best way to approach it would have been to do a triple pass. One right in the corner then followed by a bead on the lower side, or downhill side, and then a final pass on the upper side, hope that makes sense. "V"'ing out the corner was also a very good suggestion. Another way is to use a side to side movement or "C" movement and go very, very slow with a slightly long arc. Not sure if maybe your rod is designed for DC?

All I got to say I wish you was closer and I'd let your excellent milling abilities mill me a base and I would love to weld them together. I will probably tig weld mine. And thanks for the idea of building the base out of flat stock. I priced a 8" x 1/2" tube and they wanted $40/ft so I found a section of flat iron for $.30/lb


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## Tin Falcon

definitely preheat and weld from both sides bevel the outside pieces. that looks like half inch thick or as you would say 12 mm material. That is heavy stuff even for a real welder. 
Not criticizing here I only have a little flux core wire feed myself so a lot of creativity to weld much .it does a fine job on 1/8 though. 
I used to do tube and plate production welding 1 1/4 inch schedule 40 pipe welded to a 4" x 4" x 1/4 plate 300 - 500 a day it was fun up until the first 10,000. but after some practice i was told by our galvanizer that the customer said we had to have a robotic welder because no person could weld that fast and smooth ! Just call me R2D2. seriously though practice, practice and watch the puddle. 
Tin


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## arnoldb

Bob, thank you. I did consider making the fillets - now I can kick my but for not doing it. Yes, it's a 220V single phase welder. I didn't know about the "slower flux" type rods; I'll have to investigate whether we have something similar here! I have a dedicated heavy duty extension cord for the welder, and I also replaced the puny short welding cables that came with it with longer and MUCH thicker cable, so that part should be OK 

Philly, thanks; next time I have something on this scale, I'll try the pre-heating; that may be why the last weld came out the best as everything heated up a lot.

Thank you Hamstn. 2.5mm ~= 0.1". I did try the side-to-side; my hand's not steady enough :big: - and I still have problems trying to lie different beads as well. As to my milling skills, thank you for the compliment, but there is a lot of room for improvement there as well. I wouldn't trade the workbits though - and I don't mean that in a bad way; it leaves each of us to practice and improve on bits we need to improve ;D. And it's a pleasure if using the plates saves you a bit of money. It's not "my" idea though; I've seen it used for lots of different projects by many people 

Thanks Tin - and don't worry; I'm open to positive criticism (I think sometimes I'm my own worst critic!) It's 3/4" (10mm) plate. I hear you on the "repeated welds" - I've done a bit of welding (nowhere near your scale though ) the last two weeks on a couple of frames from 1/8" (3mm) thick angle iron for a friend. On the last couple of frames I could weld everything up and by the time I did the last weld, I could just sit and wait for it to cool down and all the flux would crack off by itself. No chipping hammer required. That made the welds on the base all the more infuriating! But practice makes perfect ;D

Today was a bit quiet in the shop; I spent the morning helping a friend (the "frames" friend) to do some plumbing; soldering copper water pipe joints with the blow torch was a breeze :big:

I first faced off the one side of the welded base frame in the mill. I made a couple of quick clamping plates from more of the flat bar I used for the base - just saw off and drill an 11mm hole to allow some pivot clearance for a 10mm bolt , and sawed the heads off a couple of 10mm bolts to make shorter clamping studs than are in my clamping kit. The "new" clamping plates was needed as the clamping plates in my clamping kit is too thick for the slots I milled in the base. T-nuts and the clamping nuts came straight from the clamping kit. I cleaned the mill table VERY thoroughly before clamping down the piece on a bit of paper to prevent it slipping:





Sheesh - a lot of "clamping" in the above description; maybe I need to clamp down a bit ;D

Then I flipped it upside down to do the other side. Same process as above - clean and a new piece of paper. With the slots now higher above the table, I needed thicker spacers for the off-set ends for clamping... I settled on using some of the triangular step blocks from the clamping kit; a small one and larger one combined to provide the height. I couldn't use the flat bar clamp plates as-is on just one triangle block, as it is both a bit soft and too rounded on the ends to ensure a good grip on the step block. I don't recall ever seeing step blocks used in combination like this to , but it worked a treat ;D:





Today was a public holiday here in Namibia... I forgot about it... Completely... Imagine my surprise when I pitched up at the bolt & nut store this morning to buy some M5 cap screws for mounting the base plate to the frame : Not having those, I could not carry on with the base, so I started on the table.
The lump of cast iron centered near-enough on the 4-jaw. Neither of it's faces was particularly square, so I chose the "best" one to go into the chuck:





As I would be doing some "interrupted" cuts because the workpiece is not entirely round, and having a skew face, I center drilled it first, and added a revolving center. This was purely a precaution to make sure the workpiece stayed in the chuck if something came loose or jammed up. Some thoughts, a prayer and a thumb-suck made me select high back-gear speed on the lathe for cleaning it up on the circumference. This worked quite well, but my first cut was a bit on the shallow side (0.2mm), and quickly revealed a hard spot in the C.I. skin:





So I re-sharpened the toolbit (that hard spot just flattened it), and took a 0.5mm (0.040") cut to try and get under the hard spot. Instead of using the apron wheel for feeding, I locked the carriage nut, and used the lead screw handwheel for feeding; that gives a finer feed than the apron wheel. This cut came out much better:





Next I faced the front down as far as I could - this face was far out of square, and with a 0.01" ( 0.25mm) infeed per cut on the topslide, with the apron locked on the bed it took a couple of passes (8 in total :) to get here:





That's where I stopped for today; had to go to a BBQ with some friends, so I stole some time to write this up after getting back. Time for bed now 

Regards, Arnold


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## arnoldb

Some more done today. I did not end up with much to show for the six hours I spent, but I'm taking things slow to avoid mistakes.

First up, I finished facing the piece - with tailstock removed. then I drilled a pilot hole through with a 7mm drill bit - pecking all the way to try and keep the hole as true as possible. The 7mm drill was just long enough for the job:





Then I drilled the pilot hole out to 13mm, and re-sharpened the tip of the carbide tipped boring bar that I broke earlier in the build, and bored the hole to 16mm dead. A test with some 16mm silver steel and I got a light push fit; precisely what I wanted. Then I bored the recess for the mounting flange with light face cuts from the inside the outside with a HSS toolbit that I ground to a good shape for this type of job on a previous occasion. This is part-way done:





Next I made the needed undercuts on the face. They came out a bit rough on the surface, as I used a threading tool to make them. Fortunately the running faces are nice and smooth - that's where it matters most for this project. Next up, it was the clamping groove. I did that with a parting tool and the lathe at its absolute lowest speed (back gear low speed). This was still slightly too fast, and I ran into problems with chatter. So I added the tailstock back for some additional support; fortunately my revolving center has a couple of different tips, and I could fit a bigger one to use with the 16mm center hole. This didn't help a lot though, so at the risk of chipping off the parting tool bit tip, I increased rate of infeed. Fortunately this worked and I soon got into the "groove" with nice chips coming off the parting tool and no chatter. A couple more passes with the parting tool, and I had the groove done:





I removed the 4-jaw from the lathe with the table-in-making still mounted on it, and set it aside. The 3-jaw went on, and I started on the main shaft. First off, cut a bit off the big bolt from the first photo in this thread:





Then gripped in the outside jaws of the 3-jaw on the non-threaded part of the bit of bolt, I lightly faced off the end and center drilled it for tailstock support. Then I rough-turned it down to get rid of the threads and then down to 26.5mm - this section will later be turned down to 25mm with some other steps and sizes included:




That's where I stopped for today; like I said - not much to show for 6 hours work! There is a bunch of chips though :big:
Fortunately we have a public holiday on Tuesday again, so I might get a bit further then.

Regards, Arnold


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## zeeprogrammer

arnoldb  said:
			
		

> First up, I finished facing the piece - with tailstock removed.



Hi Arnold...

I didn't understand the above. Why did you remove the tailstock?

On a related question (and apologies if this is off topic)...do you (or others) remove the tailstock when it's not needed? Or just leave it mounted and slid out of the way? I tend to always take it off when I don't need it but then I'm left with 'where to put it'. My suspicion is that it just has to do with convenience...leave it on if it's not in the way.) Thanks.

I hope the BBQ was good. You didn't mention how it went. ;D I've yet to get a grill. I need it to become 'the complete man'...along with a riding lawn mower and a bowling ball. ;D


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## Deanofid

It looks like good progress, Arnold. You're working some pretty large pieces, there!



> Some thoughts, a prayer and a thumb-suck made me select high back-gear speed



Yes, I think this is the way the professionals do it. ; )

Zee, in reply to your general question, I leave the tail stock on unless it's in the way, on my Atlas. On my little Taig, it's always in the way unless I'm using it.

Dean


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## Maryak

zeeprogrammer  said:
			
		

> On a related question (and apologies if this is off topic)...do you (or others) remove the tailstock when it's not needed? Or just leave it mounted and slid out of the way? I tend to always take it off when I don't need it but then I'm left with 'where to put it'. My suspicion is that it just has to do with convenience...leave it on if it's not in the way.) Thanks.



Zee, The only time I remove the tailstock from the bed is when I need to get the saddle back that far. Normally a fixed steady also comes into play as well. Now back to Arnold's Rotary Table.

Best Regards
Bob


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## arnoldb

: - I lost a LOT of post replies yesterday evening; I think all of them went to the old server. Having said that; it's not too bad; I'll revisit the W.I.P. section and repost as soon as I can. And many thanks to Rick and everybody who helped with the server move :bow:

Carl, thanks - the BBQ was great ;D. No Namibian is EVER without a grill :big: - but we have no use for bowling balls and ride-on lawnmowers ; only one bowling alley in the country I'm aware of, and small lawns (for those that do have them and can afford to pay for the precious water)
Machining questions are never O.T. ;D - and it was actually my bad; I should have said "removed tailstock _support_". In answer to your question though; my lathe's tailstock is on it nearly permanently; it only comes off for proper cleaning, and (very seldomly) if I need space. For the most part, if it's not in use, it is parked at the very end of the lathe bed. Like Dean said; it depends on your equipment. And like Bob commented; on the rare occasion where I needed to remove it to fit a workpiece, the fixed steady was always needed.

Dean, thank you ;D - I always thought the professionals pored over tables and calculated feeds and speeds in great detail :big:

Bob, thank you; I'll get back to it right away 


This afternoon I flipped the main shaft-in-making in the 3-jaw, and turned the flange section that mounts into the back of the table. The outside of the flange actually becomes a register to keep the shaft concentric with the table, and was turned as accurate as I could for a light push fit into the hole in the table. For some reason I got a poor surface finish; but cannot do anything about it now. This photo shows the part with the right hand section turned down to "register" size and the end already faced:





Next I used a right-hand knife tool to remove the excess metal and get the flange down to the needed 6mm thickness:





Action photo of drilling a 13mm hole part-way through the shaft - I love it when the swarf comes out in nice consistent curls like the ones lying below on the apron:





Boring the hole out to 16mm - after each pass I had to stop and remove the "rat's nest" that formed:





And done with the boring; the 16mm silver steel rod is a smooth fit in there - it acts like a piston and with the air trapped in the blind hole it pushes itself nearly right out again  - I wish some of the pistons and cylinders I made so far was that close:





For the next bit I could have done with a rotary table :... I was too lazy to set up the dividing head in the lathe. So I decided to use the 3-jaw chuck as indexing device on the mill table. I clamped two blocks about 60 degrees (relative to the chuck outside diameter) to the mill table, and for the third side, I used a clamp and step block from the clamping kit. To mark index, I used the little square shown and just lined it up with its lower edge parallel to the T-slot, and used one of the chuck jaws sticking out slightly to get the first index position:





I centered the chuck using the table feeds and a bit of that 16mm silver steel in the drill chuck to go into the hole, zeroed the X handwheel and dialled in the 17.5mm offset I needed. Drilled the first hole, loosened the clamp, rotated the chuck against the fixed blocks to maintain position, and indexed with the little square on the same "side" of the next jaw. Clamp down the chuck again, drill & repeat for next hole... QED :





Next the holes needed countersinking from the back side... My countersink bit is too big, and waaay to short to reach in there. A broken 8mm drill bit volunteered, and I carefully ground its end to a 90 degree angle with suitable cutting faces. That made countersinking easy, and the holes turned out quite well with no chatter:





The last step today, was to punch a witness mark into the flange and the back of the table; these I then "connected" with a scribed line - this will be used to make sure everything can be put back exactly the same at a later stage: 





Progress thus far:





Pretty soon now I'll get into the more challenging bits of machining  - I'm looking forward to that!

Regards, Arnold


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## SAM in LA

Arnold,

Looking good.

SAM


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## Philjoe5

Arnold,
Progress is being made here. It's looking more and more like a rotab!



> I love it when the swarf comes out in nice consistent curls like the ones lying below on the apron:



I have swarf envy. Those chips look good enough to be bronzed and mounted on a pedestal :big: I wonder how many folks would see beauty in those curly chips? ???

Cheers,
Phil


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## joe d

Progressing VERY nicely, Arnold! :bow: :bow:

This is going to be a an attractive bit of kit.

Cheers, Joe


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## Deanofid

You're doing a fine job of it, Arnold.

 Thm:

Dean


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## arnoldb

Sam, Phil, Joe and Dean - Thank you for your comments 

 :big:, Phil, the thought occurred to me to take some of the swarf and paint it in funky colours, shove it in a vase, and pass on to a girlfriend in lieu of flowers ;D. For the X - leave as-is & let it rust :big:. Seriously though; I'm happy to see the swarf like that as it means I'm putting on nice and consistent feeds - plus it's easier to clean 

Not much done today; but some none-the-less.

First I turned up a close-fitting transfer punch for the holes from some silver steel:




That was heated up to bright cherry / cooked carrots colour (For me its orange-red ;D) - hot enough to heat-treat, and dunked in some old motor oil I have for this purpose to harden it.

Then I used the punch to mark the table for the screw locations; simple; keep the alignment mark I made aligned; the punch is a close fit in the holes and stands upright by itself in each hole; and a good whack with a hammer on it and each center is marked:





I carefully centered and drilled each hole 4.2mm and 7mm deep on the mill with the chuck clamped to the table. After each hole, I used the drill chuck as a guide to run in the first tap from my M5 tap set. It only left a couple of threads on each hole before bottoming out, but enough to start the 2nd tap outside of the mill on the workbench. Each hole was run down with the second tap till it bottomed. Then the holes were run through with my modified version of an M5 plug tap - it had a pointed tip that I ground down while building "Fred" to really thread some holes to the bottom:





I purchased some Allen drive M5 countersink machine screws today. :wall: - when I measured everything initially, I only had some slotted head ones available, and the new ones' heads are bigger. I turned the excess off using the collet chuck in the lathe, but now the screws stand slightly too high. I don't want to face them off, as the hex sockets in them is not all that deep, so I'll make the countersinks on the flange a bit deeper later on if the heads interfere with the bearing. I want to use these screws, as they are high-tensile steel compared to the soft galvanized slot-heads I have. Today's final bits - screws in place and a "quicky" transfer punch:





Regards, Arnold


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## ksouers

The project is looking great, Arnold. I'm following it closely.

A tip for using a transfer punch in an awkward situation such as this: Just use a couple light taps, just enough to start the divot. You will be less likely to move your parts alignment. You can came back later with the mating part removed and give it a proper mark with a center punch. 

Also, a bit of white glue will help hold the parts aligned. White glue is sold in the US under the Elmer's brand name, maybe they have some in the crafts stores or apothecaries in Namibia. It's soft enough the pieces can be pulled apart and it's water soluble so it's easy to clean up.


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## arnoldb

Thanks for checking in and the advice Kevin ;D. I did actually re-punch the holes afterwards. I'll have a look into the "white glue" - we do get a water based white wood glue here (called Ponal, made by Henkel), but thats not water soluble once dried... Or are you talking about a glue more like the "paste" for paper etc. Never seen "Elmer's" glue - chance is if I saw it the first time without you mentioning it now, some of Mr Verburg's methods would become suspect :big:

Today's little bit...

I mounted the 4 jaw with the table/shaft assembly back on the lathe. I know my 3-jaw grips eccentric by about 2 thou - but dead parallel from the chuck to about 100mm away from it - on a 26mm workpiece, and when I tested the shaft on the whole lot as mounted now with a dial indicator, that's what I got. About 0.05mm eccentricity along the shaft's entire length, but it was parallel. The outside of the table part as mounted was still spot-on center. So I carefully turned down the shaft part to the needed 25mm for the bearing inner race; it was at 26.5mm so for a first cut I just took off an infeed of 20 thou (that takes _just) over 1mm - off the total diameter). Then I measured the piece to be sure - it was down 25.48mm. I honed the cutting bit in-place on the lathe; just a couple of light touch with the oilstone - then went down to just over size at 25.1mm. A last cut part-way for the last 0.1mm, and I stopped for a test with the bearing and it lightly pressed over - so I finished the cut:




Not super-smooth, but I'm happy with it.

And a final test; the bearing goes on all the way with a light push - just "some" pressure required ;D:





Next I turned the shaft down to 24mm up to a point 15mm away from the base of the table; the bearing is 17mm thick, and with the slight indentation in the table and the offset lip in the bearing mount hole in the base, that leaves me room for threading and run-out to the bottom of the bearing inner race. The 24mm section will be single-point threaded at 1mm pitch for the bearing pre-tensioner nut. I stopped short of the threading; that will take a while, and had better wait for the weekend.

Looking for something more to do, I decided on doing the holes to bolt the base top to the frame. I forgot to mark out the circle the table would run on on the base top plate, and being hit by a sudden sense of aesthetics, I needed to "see" a ring on the base top plate where the table would run. I pressed the bearing in the plate, and fit the whole lot over the shaft and used a permanent marker to mark the outline of the table on the plate:




 :-[ OK - I'll admit; I just wanted to see and feel what it would be like to have the pieces together ;D

With the mentioned aesthetics in mind :, I marked out and punched for the centers for the hold-down cap screws:




I stopped there, as while punching the holes, I found my concentration wandering to what I'll have for dinner, and also distracted by the swarfmagnets bashing around their stainless food bowls (must have had the same thoughts :big

Regards, Arnold


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## arnoldb

I had some more shop time today, and quite a bit of it was spent on something I particularly like - single point threading.

First thing, I decided to make the pre-load nut. I removed the 4-jaw chuck (with table in making et al) from the lathe and put back the 3-jaw with outside jaws. Some 50mm aluminium rod was then turned down to just under 40mm for just long enough to make an 8mm wide nut and allow parting off. Then I drilled it out to 19mm for the same depth (19 mm, as it is my biggest drill):





And parted off:




The white liquid is synthetic water soluble oil mixed with water. Normally I would have used methylated spirits on the aluminium, but I ran out. Sometime in the past, I did try this soluble oil on aluminium, but had less-than-satisfactory results on a 20:1 wateril mixture as recommended for this oil. This is a "new" batch I made up just the other day, and through a fumble, this mix is more like 10:1 - and it worked a treat on the aluminium!

Then I changed back to inside jaws on the chuck, and chucked up the parted off bit of aluminium. It needed to be bored to inside diameter thread size next. I originally intended to thread the nut and shaft M24x1. The change wheels for turning a 40 tpi thread was still mounted (from making the Dremel chuck adapter for the mill here).
My thoughts went as follows: "I'm lazy to change the gear train. Would this much finer thread work ?... It would actually work well for the pre-tentioner nut - finer adjustment control and more than adequate grip. PLUS - I can use the thread dial indicator instead of reversing the lathe after each cut." Choice made ;D
For running a 40 tpi thread with a 60 degree angle, the thread depth would be 12.5 thou - roughly 0.32mm So the Inner diameter of the nut needed to be bored to 24 - (2 * 0.32) = 23.36mm. I bored it to that, and started setting up for threading.

I have a little multi-purpose boring bar I made out of an old carbide tipped tool shank that takes 4mm HSS inserts. I had a 60 degree threading "insert" already, so I put that in. Here I'm setting it to center height using a gauge I made as one of my first lathe tooling projects: 




Note that the tip is upside-down. When I do internal threading, I do it with the tip upside down and cutting against the back of the workpiece. This allows me to do normal infeeding, and I can see what's happening in the cut. It's just easier for me ;D

Next I set the toolbit square using a fishtail gauge; the piece of paper is not to hide the swarf below for the camera shot, but to make it easier to see the tool tip relative to the "V" in the gauge. To set the angle like this would be tricky on the workpiece itself, so I used a length of silver steel chucked in the tailstock drill chuck to do it:





The toolbit approaching for a cut:




This looks like I'm running at high speed, but actually I was running at the lathes second lowest back-gear speed. I didn't try to take a photo while in the cut; had to mind the leadscrew disengagement lever then 

The finished threads after taking 2 thou cuts per pass, and about 2 passes on the same cross slide setting for the last two to work out the "spring" in the boring bar:





I then put the 4-jaw with contents back on the lathe, and turned the threads on the shaft. I was lazy, and just turned the insert bit in the boring bar upright again - that eliminated the need to set up a new toolbit - and turned the external thread on the shaft with it. The only thing I did before turning the thread, was to use the edge of a half-round file to make a thread run-out groove. When approaching final dimensions, I just tested with the nut for final fit. Here the thread is finished and the nut screwed on:




It looks a bit rough in the photo, but actually the nut spins about 1/3 of the length of the thread with a flick of the finger before it stops ;D

Next I did some more work on the nut in the mill. I want to be able to lock that nut in position when fitting the table together, so it needed some method of achieving this. I slit and counterbored it on one side with a 6mm center cutting slot mill to clear the head of an M3 cap screw, then center drilled the bottom of the counter bore, and ran a 2.5mm drill (that's for M3 tapping) right through, and then just drilled 3mm down to the slit for thread clearance. Then the 2.5mm section remaining below the slit was tapped M3 for as deep as my taps would go. I also milled two opposing flats on it for use when tightening it up. I didn't take photos of every step mentioned here; but here are two I did take:









And finally - where I stopped for today, and how the nut will be used:





Regards, Arnold


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## zeeprogrammer

Very nice Arnold.
Your work always looks production quality to me.


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## Deanofid

It's looking great Arnold, and you're getting on with it pretty quick, too. I like the split locking collar you made here. Do you plan on lapping the mating surfaces of the table and body? 

So, you like single point threading, then. Me too! Just seems fun to me, (as long as the threading dial doesn't come loose..).

Dean


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## Philjoe5

Great documentation Arnold as usual. It's looking good. That threading job looks super :bow:

Cheers,
Phil


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## Noitoen

Is that a thrust bearing or is it a regular one? If it's a thrust one, it looks like it's mounted the wrong way around ???. Otherwise, nice job on the table.


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## arnoldb

Thank you Zee - I'd get fired in a production environment though; I work waay too slow for that :big:

Dean, thank you. Yes, I'll lap the mating surfaces - not to a mirror finish though; only till operation is smooth. The fine "grooves" from facing the top of the body will help with oil retention. 
I do like single pointing; its extremely satisfying to end up with a good thread. Many people dread single pointing, but I think its one of those jobs where its mind over matter - and a couple of simple rules to follow. Maybe I must post a full write-up on the way I do it at some point; any takers out there ?

Thanks Phil ;D

Helder, thank you. It's an angular contact bearing. It is mounted the correct way around as shown but maybe counter intuitive without the rest of the assembly. The outer race will be pressed into the top of the base from the bottom (underside). When the table is then installed from the top, the nut is used to screw up against the inner race of the bearing to pre-load it - This should become clearer when I get to the point when I start to fit things together.

Today's little bits...

First thing, I wanted to get the top plate of the base bolted to the frame; I'd marked it out already for the bolt holes, so I just needed a way to make the whole lot stay together for drilling and so on. I sawed two longish strips of 20x5mm flat bar off a length I keep handy for incidental needs such as this. Both strips were drilled for clearance holes for some 6mm cap screws, and then the top plate and frame were bolted together like this:





The bottom strip of plate is through the mounting slots of the base.

Then I clamped the whole lot down square on the mill table; there is a clamp on the hidden side in the other groove of the mill table:




I forgot to put a piece of paper below it....

Then I started drilling all the holes. Even though I had laid out the hole locations, I decided to go for X and Y coordinates using the handwheel calibrations - as each hole had to be center drilled, then tap size, for clearance trough the top plate and finally counterbored for recessing the M5 cap screws I would be using. So I located the edges of the right front corner the primitive way; with a bit of 6mm silver steel chucked and a piece of paper. (Aside - I've had some great news today; I will be the owner of a proper edge finder soon ;D - THANKS MATE!) Then I started counting turns and reading handwheels while center drilling each hole, and jotting down the figures on a bit of paper. Here all the holes are drilled to tap size (4.2mm):





That lot was followed by a 5mm drill just deep enough to provide clearance through the top plate. The heads of the cap screws measured out at 8.4mm in diameter and just below 5mm high, so I used a 9mm mill to counterbore the clearance holes 5mm deep. My advanced lubrication delivery system is the orangey bottle in the right of the photo :big: :





With all the holes I needed to tap full of swarf from the counter boring, I used a drill chuck with a 4mm drill to manually clean out the holes. Just plonked the lot on its side, and by hand turned the drill in each hole to get the swarf out. Photo without the hand that should be turning:





Then I sat down on the bar stool I keep handy (my "working table" is a bit high), and tapped each hole. The 5 mm clearance holes in the top plate are excellent tap guides to keep things square when starting with the first tap, so nothing fancy required as guide. Just manual work ;D. I'm due for a new set of M5 taps though; I could feel these starting to struggle, but they have tapped many tens of holes in the last two years... All bolted together:




Things went well didn't it ??? - Well NO - If you look carefully at the left hand hole in the top row in the picture, you'll just see the mark where the end mill wandered when the lot came loose on the mill table. Remember I said I didn't add the piece of paper below when clamping ? :wall: Fortunately I could recover; and another mark on the table to serve as a reminder... I think I can still hear some bad words echoing around the shop; fortunately Shrek was out of earshot!

With the base finally together, I started on the gear. A slightly oversize chunk of the phosphor bronze getting sawn off:





Then faced and bored in the 3-jaw:





Next a section of the left-overs from that old big bolt was turned down for a press fit in the bore in the PB ring:





Then I sawed off the turned section of steel, and dumped it in my freezer on top of some ice for 10 minutes - it was nice and cold then ;D
It pressed into the ring in the bench vise without too much effort, enough to give a good press fit, but not so much that the PB ring would crack:





Some more turning, and I have the makings of a gear:





I need to double check some calculations now, and run through the needed steps in hobbing the gear in my mind, so updates might be a bit slow for the next couple of days. Think thrice - machine once...

Regards, Arnold


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## Deanofid

I don't see the end mill marks, Arnold, but I'm not looking for mistakes. I'm looking for success!

For the lapping bit, I didn't make mine shiny either. Just smooth, although it has a gray appearance. Doesn't matter, as it's out of sight under the table.

That's a nice chunk of bronze you have there. Will be good to see it being turned into a worm gear. Are you making the worm, too?

Dean


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## keys

Is the paper under the piece to keep the part from sipping? Is that something that should be done to the vice as well?


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## arnoldb

Dean thanks. I thought as much on the lapping; it should end up with a dull grey appearance. And Yes ;D I'll be making the worm as well as a hob.

Justin, yes the paper is to keep it from slipping. I don't think it will be needed below your vice, as it has a much bigger contact area; as long as you bolt it down well. It won't do any harm though; just squirt the paper with oil if you put it there for extended periods; to keep things from rusting where you can't see. These are just my thoughts though; some more experienced people might disagree with me; in that case I'd be happy to be put right.

Today's bit; Dean was reading my mind ;D. I need the hob before I can cut the gear, and while making the hob I can just as well make the worm. Attached is an Excel spreadsheet I set up quickly to do some calculations from information I drew off the Internet. An interesting thing I found was "crowning" of worm wheels to make sure that the worm/wheel combination can stay properly lubricated. The crowning entails cutting the gear teeth with a slightly bigger hob than the worm would be. Just for the heck of it (nothing like learning from testing) I'll be doing this.

There is a good amount of information on gear calculations here on HMEM as well as on the web, so I won't go into detail except for that my original planning was for a 72 tooth MOD 1 wheel with a 20 degree pressure angle. Screwcutting for MOD 1 is pretty close to 8 TPI - and bliss; my lathe has an 8 TPI leadscrew. 8 TPI calculates back to about MOD 1.01 - so that's fine with me - I'm lazy to set up weird & wonderful combinations on the change wheels, and this is one of the easiest to set up.

First up, I needed a toolbit with the correct shape; a point with a 40 degree included angle; clearance for helix angle, and so on. I marked out an 8mm bit of HSS for the angled tip using a protractor:





A couple of minutes (well, about 20) on the bench grinder, and then some manual work on the oilstone, and I ended up with this:








In the first of the above photos, you can clearly see the the bottom of the bit is at an angle to the top; not straight down. This is for adequate clearance of the helix angle; I did not calculate that or anything; just ground it on by gut feel. Also, you will notice I didn't touch the top of the toolbit with the grinder or oilstone; the original ink I marked out with is still on there.

A trial run to measure sizes on the worm-in-making from some 16mm silver steel. I added a lot of run-out space at the headstock side, as this is a fairly coarse thread and the space is needed to stop. I also have the topslide set parallel to the work and locked, as I might have to add some additional side-feed with it to make cutting easier if it becomes too difficult. (That's frowned on by screw-cutting purists, but have stood me in good stead on large threads like these in the past):





I stopped with the threads half-done for tonight. Just jotted down the necessary readings from the dials so I can continue from there when next I have shop time:




And yes, it's slow going; I don't have space to add tailstock support, so I go in 2.5 thou infeed steps with a repeat pass at the same depth after every 10 thou.

Regards, Arnold 

View attachment GearCalc.xls


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## Philjoe5

Arnold,
Thanks for documenting the making of a hob and gear. :bow: Though I have no immediate need for it, it's something on my to-do list at some point. I've taken a seat right near the front of the class since I don't want to miss anything :

Cheers,
Phil


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## Deanofid

Good start on it, Arnold. Looking good!
Dean


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## arnoldb

Phil & Dean, Thank you ;D

Phil, I hope I don't set a bad example though; this is my very first attempt at something like this - I'm purely putting theory from a lot of research into practice. There might be gotcha's somewhere - if so, I'll be sure to post that as well.

I've had a slow couple of days in the shop; had to attend to domestic and social duties for a change...

This afternoon I finished off the worm; it was a simple process of finishing of the threading, drilling it through and reaming for an 8mm shaft. I then parted it off at length leaving a shoulder, in which I cross drilled and tapped for an M4 grub screw (set screw). All done:





Next I started on the hob - after honing the edges of the toolbit again. The threading process is exactly the same process as for the worm, but the hob is 1mm larger in diameter as I explained in a previous post. I didn't take photos of the threading done on it; except for a close-up of a bit of swarf that came off while I was turning it. Why? - the swarf shows that the toolbit was cutting properly on all sides and the front:





Today's progress. When I have shop time again, I'll mill teeth and some clearance into the hob:





Regards, Arnold


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## Deanofid

Good stuff, Arnold. That worm looks about as good as any I've seen from the factory. Very pro!

Dean


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## Philjoe5

Nice looking worm Arnold. :bow: Thanks for the update

Cheers,
Phil


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## bearcar1

Good heavens Arnold! I did not notice this thread, hmmm. Anyway, WOW! What a great start, I fully appreciate the work you have put into making that gear hob and cutting those threads, well done indeed!

BC1
Jim


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## arnoldb

Dean, Phil & Jim, thanks guys ;D
I'm normally very critical of my own work, but for once I even admitted to myself that I'm happy with how the worm turned out. Not perfect, but I'm happy.

This afternoon I milled the cutting teeth into the hob; no fancy setups for indexing; I just judged by eye for indexing, but I took pains to make sure I got the cutting edges dead on center, and triple-checked that I was cutting the teeth for right-hand rotation of the hob when in use. (  sometimes I learn from other's "oopses"  ) 





Instead of milling clearance behind the "teeth", I just took a file to it; 5 minutes in all, and I had some clearance behind the teeth all round. I didn't want to take away too much for clearance, as the hob will be used to auto-rotate the gear blank when I eventually get to cut it. I didn't bother de-burring anything either; the heat treatment will get rid of some burrs, and once hardened, I'll give the cutting edges a once-over with the Dremel with a grinding stone to really sharpen them up - and should remove any left over bits of burr. In this photo you can see how I filed clearance to just behind the tips of the teeth - there's a little facet left just on top of the tooth cutting edge that I did not touch with the file:





Another view of the "profile" - as one can see, my "by-eye" indexing was not spot on :big: :





Regards, Arnold


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## Artie

Hey Arnold, intensley interested in how this is going to go.... just stripped a worm gear on my lathe so this is right up there in the 'how to' thanks mate looking great!

Rob


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## Maryak

Arnold,

Nice spiral hob. :bow: :bow:

After milling the teeth, I found the only way to get the profile correct and remove the milling burrs was to reset it up in the lathe and lightly skim the grooves or for you, lightly skim the thread. When I was happy with the profile then on to the heat treat.

Hope this helps

Best Regards
Bob


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## arnoldb

Thanks Rob - its a pleasure ;D

Bob, thank you ;D I thought about skimming the threads again, but I chickened out on that one... I've "picked up" partially turned threads in the past, but with this one I was hesitant, as I do not know how my lathe would handle a picked up and interrupted thread cut... I ended up cleaning the worst of the milling burs with a needle file - tooth by tooth :

Today's bit involved more thinking than working. Like mentioned, I cleaned the milling burrs off the hob, and then hardened it. This is a fairly big bit of metal, so I went outside and heated it with my butane torch (took quite a while to get it to temperature). When I thought it was about right, I heated it some more, to allow me enough time to turn the torch off first and then plunge in the oil bucket. This is for safety - I don't allow any flames (not even a lit cigarette) when I do an oil dunk, as the smoke coming off is potentially very explosive - and yes - I am positioned between a fire extinguisher and the dunk site to allow me to pick up the extinguisher while departing a possible fire. If you have the luxury of choice, rather use water hardening than oil hardening silver steel. 
Once cooled, I carefully hand-ground the cutting faces with the Dremel and a small green grinding wheel. Everything feels nice and sharp, and the burrs are gone completely:




I'm not going to temper the hob; I think it will do just fine on the phosphor bronze wheel as-is.

Next I turned down and bored out the gear blank to size - well on the OD at least. I miscalculated the last feed while boring, and ended up with the hole 0.1mm over size :wall: Fortunately, I can still compensate for that mistake, as I haven't turned down the shaft yet for mounting the gear:





The gear is too small to hold in the chuck for gashing (well, either that or my slitting saws are too big :big, so I turned a mandrel for mounting it further away:




The mandrel was turned in my 3-jaw and never removed - the gear blank was just mounted on it, and the chuck taken off the lathe.

Then the thinking started... How was I going to mount my Myford dividing head on the mill scratch.gif The T slots are not compatible, I needed a way to tilt it (rather than tilting the mill head, which I spent a LOT of time recently tramming in) and also get adequate workspace. I ended up choosing my lathe's swiveling vertical slide to mount the DH on - that will allow me to set the angles needed. I set everything loosely in place on the mill table to see if I could get adequate clearances everywhere and be able to cut some chips without running out of travel:





The last challenge was mounting the vertical slide to the mill table. I nearly started cutting metal to make new T-nuts and so on, when I noticed the cross-slide extension I made for the lathe about 2 years ago. Some checking followed; and YES! - I can clamp it to the mill table to mount the vertical slide on. The completed assembly looks like the cobbled together solution that it is, but it should work:





That's where I stopped; I'll do the gashing when I'm fresh tomorrow morning; lot's of dividing to do.

Anybody with sharp eyes might have noticed I didn't turn a radius on the gear blank - I just noticed it now while posting  - I'll either have to take the chuck back to the lathe to do it, or use an end mill to make it...

Regards, Arnold


----------



## Deanofid

Good thinking for your setup, Arnold. You give a lesson in using what you have!

After the blank is gashed, will the cutter rotate the blank around as it's cutting the teeth?

Dean


----------



## arnoldb

Thanks Dean ;D


> After the blank is gashed, will the cutter rotate the blank around as it's cutting the teeth?


 ;D ;D ;D Yes that was the plan, and it DID ;D ;D ;D

I'm a lazybones; normally I sleep till 9 or 10 am on a Sunday. This morning I awoke at 6 am with the same feeling of anticipation as a 6 year old on his birthday, and just could not get back to sleep... Once in a rare while I get days like this, and I cherish them; things were going to be good.

When I heard all the neighbours were awake I headed for the shop.

The radius I forgot to turn yesterday was just over 10mm to a depth of 1mm - I used a 10mm slot mill to make it, hoping that the tendancy for slot mills to cut slightly bigger than their stated size would do the job. I just cranked the dividing head through 3 full 60 turn revolutions - first infeed cut 0.5mm deep, second as well, and for the third one left as-is to do a final cleanup. Light feeds, as the setup most definitely is not as rigid as one would want:





Next I set the whole lot to the needed 4.5 degree angle from horizontal. This meant my center reference to the blank was gone. Measuring things were difficult - well pretty much impossible - but fortunately I did zero the mill on all axes before changing the angle. I was able to calculate the new "center cutting spot" from those with a bit of trigonometry, and dialed in the differences as appropriate. I then spent more time checking that I did indeed change the angle in the correct direction - upwards vs downwards, and that I didn't make a mistake in my calculations. My dividing head is based on a 60 tooth worm, so some calculations and it turned out I needed to stop on every 35th hole on the 42 hole plate to make a 72 tooth gear. 

I changed plates (rotten luck; of my 2 plates the wrong one was on :big and set the index fingers on the DH and started slitting. One round of 0.1 mm deep slits to check:




I even counted the "teeth" to make sure I had 72!

Satisfied with the above, I repeated a full rotation of slits to a depth of 2.5mm:





I have 2 slitting saws; the 1mm thick one I used above, and a 0.5mm thick one of the same dimensions (brand new; never been used before). When I checked visually with the hob against the slits, I wasn't sure that it would have enough depth to start auto-rotating the blank once I got to hobbing. So I added the second slitting saw to the mandrel - without removing the mandrel from the collet chuck - and then lifted the Z feed by 0.25mm to account for the "new" total thickness of 1.5mm. Then I ran a full revolution again slitting only 1.2mm deep with the thicker combined saw. If you look carefully, you can see the additional cut in the grooves:





With the blank now slit, I needed a way to hob it. I have a bunch of old bearings I get from a local auto-electrician for free - and I selected 2 of the same size with a slightly larger ID than the gear blank - but that were still "sort of OK". Then I dug around for more bits and bobs, and once found, I turned a mandrel to suit the bits 'n bobs, gear blank and bearings from some HRS rod.





The Bits 'n Bobs mentioned is a block of brown stuff... My metals are too precious to waste on a once-off use like this, so wood it will be. With the 4-jaw still occupied by the table-in-making, the wood "jumped" onto the face plate after some persuasion. I then started boring out a pocket to fit a bearing in - after center drilling and drilling a 6mm hole right through the block:





Once done, I flipped it around, and used the mentioned drilled hole to set the block on center again and re-attach it to the face plate:





I then bored a pocket for the other bearing, and also cleared out the center bit to allow the mandrel to pass through:





"Gotcha!"s and notes at this point...
1: A note: I made the mandrel so that it would pre-load the bearings while tightening down the gear blank on its end. I don't have a picture, but if anybody wants one, I'll be happy to make up a quick C-o-C of what I mean.
2: A Gotcha: When I drilled clearance for the center hole in the wood block, I forgot to make it big enough to clear the bearings' inner races. When I fit everything together and tightened up to pre-load, everything froze up. I ended up fashioning clearance for the inner races with the Dremel and a smallish routing bit. (Too much work to re-setup everything on the face plate!)
3: Another Note - the method I used is to make this "jig" is VERY crude; it worked for me - I think primarily because I did take the time to make sure both faces of the wood block were parallel, and one side (that was then marked as a reference side) was square to the faces.
4: A Gotcha: Cleaning wood off a well-oiled lathe is a bugger :big:

I then clamped the wood block with bearings et al on the mill, standing on the mentioned "reference" side. then with the hob in a collet, I advanced on the Y axis, turning the mill chuck by hand until I could see that everything would mesh, and the blank would auto-rotate. Then I set the mill to it's slowest speed, held my breath and started up. I nearly fainted from holding that breath; things were going really slowly :big:, but the wheel started revolving, and bits of swarf started appearing. I made a mark on the blank with a permanent marker so I could judge progress around, and I slowly started feeding in 0.1mm for every revolution of the blank. after about 5 passes, I stopped, selected the next higher speed on the mill, and started off again; a bit quicker:





I can scarcely describe the feeling of immense gratification (and joy!) of the proper profile slowly appearing on that wheel ;D
The end result - fresh off the mill:




Sorry; the photo is a bit out of focus; its pretty hard to try and take a photo of this!. As you can see, the profile is slightly offset to the right -but it will do for me for now.

The worm meshes with the wheel beyond my expectations:





I then chamfered the edges of the wheel:





Another note: From the above I obviously gashed the teeth too deeply with the slitting saw, but that was the only way I could ensure proper meshing for auto-rotation. I think this can be eliminated by using a much smaller slitting saw - or even better, a little cutter made up to the same OD as the hob with some taper on it's edges.

Having said that though; I'm over the moon - I've never ever made a gear, and for a first foray into gear cutting, this came out MUCH better than I expected - especially for a worm & wheel setup ;D ;D ;D ;D (Can anyone tell I'm happy :big

Regards, Arnold


----------



## RobWilson

Hi Arnold  :bow: :bow: :bow: :bow: :bow: :bow: :bow: great job , turned out spot on Thm:

Regards Rob


----------



## SBWHART

Great stuff Arnold

I could see where you where going with the wheel its a method I've seen done many times before, never actually done it myself, but I was keeping my fingers crossed for you all the way.

Real nice work and very well shown.

Stew


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## Maryak

Arnold,

Congratulations that's a great way to worm yourself out of a difficult job :bow: :bow: :bow: :bow:

Best Regards
Bob


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## Deanofid

Splendid work, Arnold! 
Watching your steps from the beginning of this gear cutting exercise a few days back, and to this completion, and knowing the direction you were headed, I had no doubts about your success, but still feel the excitement radiating from your shop.



> As you can see, the profile is slightly offset to the right -but it will do for me for now.



Do you mean the cut is slightly more on one side of the blank? A very small amount, if that's what you're referring to. Won't make a whit of difference, anyway. The worm doesn't know.




> I've never ever made a gear, and for a first foray into gear cutting...



No one makes a worm and wheel as their first gears, Arnold. I don't know what you do in "real life", but you are a natural born machinist. Such a canny fellow! 

Really impressed, and happy for your accomplishment,

Dean


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## Philjoe5

> I'm a lazybones; normally I sleep till 9 or 10 am on a Sunday. This morning I awoke at 6 am with the same feeling of anticipation as a 6 year old on his birthday, and just could not get back to sleep



I've gotten this feeling more times since working in this hobby than I can count. It's what keeps us young, or at least thinking young ;D

Good job on the gear and many thanks for the tutorial on making it. :bow:

Cheers,
Phil


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## arnoldb

Rob, many thanks Mate ;D - now you can stop the stickpoke on the gear :big:

Thank you Stew ;D - You can uncross your fingers now  - I'm sure I'll use the same basic method in future!

Thanks Bob ;D ; I can be a wriggly one sometimes... This was like a chess game; thinking through the moves and scenarios were much harder than actually moving the pieces to get to the end result. 

Dean thank you ;D - Yes; the cut is about 0.2mm to one side; the worm won't mind - but I do :. In real life, I'm an "IT Administrator" - a very general term, as I look after the computer hardware/software/users/security/programming, HSE, building security etc. at the company I work for. I have a fairly broad technical background - originally qualified in electronics engineering, always interested in all forms of engineering, and done some interesting electronics security systems design, industrial process control systems and simulation software as a sideline to earn additional income. Before I bore everyone to death, I'll admit that I'm by nature very technically minded, and inherited this trait from both my father and grandfather. Just don't ask me who starred in _this_ and _that_ movie :big:

Thanks Phil ;D - and it's my pleasure to share - especially if my ramblings are useful to someone. I know what you mean; about the same feeling as finishing an engine and see it run for the first time. Now I have to get this RT finished and build an engine for a change! 

Today's little bit is pretty boring. I milled three small flats on the gear flange and drilled and tapped in those for 4mm grub screws. Then I turned down the end of the shaft for a nice slide fit for the bore in the gear wheel, and milled flats on the turned down section for the grub screws to tighten up on:





With the dividing head still mounted on the mill this was a breeze. I'll make a dedicated mounting for it at some stage though; as the setup is far from rigid enough for serious work on steel - and I have quite a couple of future projects lined up that will require some gear-making.

Everything so far assembled for a look-see:




A bit of a revelation to me as well; the ideas I had for making the worm shaft adjustable just went down the drain; not enough clearance, so it's back to a bit of head scratching. And people wonder why I'm going bald... :big: At least it makes cleaning chips out of the hair easier ;D - life always have a positive side!

Regards, Arnold


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## Hamstn

hi Arnold, great job so far. I finally got some pictures and time to start my project and will start a thread soon.

I am at the point to add the worm screw also and I have been thinking on the idea you had to make it adjustable. I was waiting to see what you came up with first but the idea I had in the back of my head has been to build a bearing block for each end of the shaft to hold the bearings and mount them inside the table. I was then thinking about tapping the sides for bolts and slotting the holes in the bearing blocks for the adjustments. Hope that makes sense. The original design had two bearings on the crank end of the shaft but My shaft is almost long enough that I think it would be better with one on each end. I am also not sure the roller bearing I have will fit so if not I will move to brass bushings.

Keep up the good work, it's above my fit and finish but should still work the same in the end.


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## Deanofid

The assembly shot looks good, Arnold. 
If that tooth thing is annoying, you could just face the gear until they are equal. I know what you mean about it. We want to get things juuust right. The functionality of the piece doesn't suffer, but the little man in our head won't leave us alone!

Thanks again for sharing. Looking forward to the next episode of "As The (R/T) World Turns".
; )

Dean


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## walnotr

arnoldb  said:
			
		

> A bit of a revelation to me as well; the ideas I had for making the worm shaft adjustable just went down the drain; not enough clearance, so it's back to a bit of head scratching.



If I may jump in here, how about mounting the worm mount shaft in eccentric bushings/bearings to adjust your backlash? It shouldn't take up a lot of room and you can dial in what ever clearance you desire. You might have to shim the gear up or down but I think it could be doable.

Steve C.


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## Florian

Hi Arnold

Well, the "commercial ones" (vertex type) use a round material with an excentric bore. And this bore holds the worm gear. Maybe there is enough space to do it that way? Oh and the worm gear on the vertex rotarys is only supported on one side! 

Florian


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## arnoldb

Thanks Dean - you're so right ;D

Hamstn, thanks ;D. Yes, your idea with slots for adjustment will work. I want to be able to completely disengage the worm easily for rapid indexing; something I need on a regular basis - for this, the slots won't work though.

Steve, you're most welcome to jump in any time you want ;D. Thanks; I initially thought about using an eccentric - then had other plans. It's definitely back to an eccentric again ;D

Florian, thank you; You've just provided the spark I needed - the shaft I have for the worm is more than rigid enough - and I now have an idea :idea: - I'll check tonight if it will work...

Regards, Arnold


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## joe d

Arnold

This is coming along very nicely. Your gear and worm look like something turned out by Rob Wilson... and that is a very good thing! :bow: :bow:

Cheers, Joe


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## arnoldb

Thanks Joe - much appreciated ;D - though there is quite a way for me to go to get to Rob's standards!

When I got home after work, I had a good look at what I have already, and an eccentric will work a treat. The gear height is adjustable - so that's not a problem; if it needs to move closer to the table top I can counter bore its face to clear the bearing pretension nut. Just some fine detail to finish off in my noggin - mostly related to the vernier scale I want on the assembly. As I'll need to turn an eccentric soon, it's time to get the table off the 4-jaw chuck. But this is no time to rush. I thought things through, and decided to graduate the table first; everything was set up ideally already; easy 72 divisions on the dividing head to mark 10 and 5 degree divisions on the table.

I haven't made a spindle lock for my mill yet, so I opted to cut the division markings rather than broach them like Dean did. Darn; all my suitable toolbits have square shanks... So first, a tool was needed. Some 10mm silver steel, a 4mm cross-drilled hole through at a slight angle (not needed here, but possibly in future) and drill & tap the end for a 4mm grub screw. A short length off the 4mm round HSS sticks I keep around; a bit of grinding, and the result:





On to the mill - with the cutter set dead on center. I fed Y till the cutter tip just touched against the side of the table, and then moved the workpiece away on X. Another 0.2mm feed on Y and then I started cutting the first 10 degree graduation. Just deep enough in on X till it looked good to me, then I set the mill table stop to stop there. Then it was turn the DH, feed X to the stop & back out; repeat till all the 10 degree marks were done:





And after repeating for the 5 degree marks on a shorter X feed:





Regards, Arnold


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## zeeprogrammer

Always good things to see and stuff to learn from your threads Arnold.
Nice stuff!


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## Artie

arnoldb  said:
			
		

> though there is quite a way for me to go to get to Rob's standards!



Hi Arnold, aint that the truth!

Mate Ive been watching this fromt the beginning and Im darned impressed, you will use this tool to death once its finished, with the satisfaction of knowing, every time you pick it up that its YOURS.... a very very nice feeling.....

Excellent stuff, many od us dont appreciate how hard it is to get 'stuff' in a place like Namibia.... well done mate...

Rob T.. (as opposed to Rob W who is mentioned above)


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## arnoldb

Thanks very much Carl ;D

Rob, thanks mate ;D - I'm sure the RT will earn it's keep - I already have a couple of projects planned where it will be invaluable ;D

Well, no update on the project tonight; Had a couple of drinks with some business associates after work, so drink in and shop out.
I might dabble a bit with some CAD though ;D

Regards, Arnold


----------



## arnoldb

I finally got the table off the four jaw chuck this afternoon, as I could not see any further possible use for keeping it mounted.
First off was a trip to the band saw to get rid of the excess:





Bandsaws being the fairly rough machines that they are - and I've taken some pains to get mine as accurate as possible - the cut will inevitably shift slightly and not be perfectly square - especially in the vertical plane while cutting. I kept a careful look on the work, and when I detected too much of a deflection in cutting lines, I would stop the machine and turn the workpiece. I did this three times, as can be seen from the photo showing the table and the offcut:




The cut took about 15 minutes to complete - but the blade I have on the machine is not exactly new any more and is begging for replacement. The offcut will make a nice cast iron flywheel for a future project ;D

Next it was back to the 4-jaw with the table. I put bits of soda can on the radius of the chuck jaws to prevent marring of the graduation marks. Then I dialed in the table dead on center on the outside body with just a vibration coming off the needle of my best indicator when revolving the chuck. This step is crucial in the long term:





I then added a close fitting 16mm "test bar" in the hole I bored initially through the table center. For me this is a length of silver steel that I know is straight; no fancy test equipment in my shop (YET!). I tested run-out on this a good distance away from the table body. This was to make sure that the back of the table is at a precise 90 degree angle to the axis so that I could turn the face completely parallel with the back side:




Fortunately my old 4-jaw is pretty darn accurate on the faces of its jaws, so I did not have to resort to tricky measures to get things sorted; It was less than 0.005 mm out at the distance I measured, and that's fine with me in the environment I have.

I then faced the table repeatedly with very light cuts - just 2.5 thou infeed at a time; I didn't want a sudden heavy cut on the irregular bandsawed surface to knock things out of kilter! Then I bored the center hole out to 20mm diameter to a depth of 5mm - this will become the register for my lathe chuck mounting plate - and chamfered the register hole and internal 16mm step left at a 30 degree angle. This is for easy location of mounting the chuck plate in future, as well as for easy centering of the RT on the mill table with a bit of 16mm rod clamped in the collet chuck. As a final step, I used a sharp-pointed threading bit to turn light alignment rings on the face 10mm apart from each other.
The assembled lot is starting to look like an RT - with the exception of the glaring blunder on the bottom right hand cap screw counterbore that caused so much heat in the shop a while ago ;D:





Regards, Arnold


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## SAM in LA

Arnold,

You are building a $1000 rotary table. It looks fantastic and I'm keeping notes on the ways you are insuring accuracy in the finished product.

SAM


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## zeeprogrammer

Awesome work and quality. Really impressive.
Don't worry about that 'blunder'...it makes it yours.
Unique.
People will know it was made by a craftsman...and not a business.


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## bearcar1

That is some fine work you have there Arnold (except for that one counterbore ;D) That would be a good spot for one of those metal ID tags, you know, to cover up the scar stickpoke I'm impressed with how you did the hash mark 'etching' NICE Thm:


BC1
Jim


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## Deanofid

Really some great quality work here, Arnold. An enjoyable thread, and hopefully it's giving folks
some good ideas. This is one of those shop projects that pays off in experience as well as tooling.

Extra good!

Dean

Oh yeah.. Position the doink toward the back when you put in your worm shaft. It won't bother 
you so much!
; )


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## arnoldb

Sam, Thanks ;D - $1000, well, then I'm not doing too bad then :big:; that's just slightly more than what a 6" import table would cost me delivered here in Windhoek! (N$6700 - and the exchange rate is currently N$7.60 to 1 US$). Besides the money thing; it's a lot of fun!

Zee, thank you ;D - If When the table is in use, I'm sure I'll forget... Except when I look at it... Oh well, one to remind me of the "Wall of learning" ;D. As to craftsman - well no, "aspiring craftsman" - yes :big:

Thank you Jim ;D - the hash marking method just seemed the simplest solution to me. Your ID tag idea gave me an idea; how about a little brass gravestone mounted on top of it - engraved "Below lies Error - Rust in piece" :

Dean, Thank you ;D. If this build log gives people good ideas, then I get triple satisfaction from it - experience, tooling and helping someone!  :big: When I did today's work I made sure doink is in the back!

I've been doing some CAD work in the eccentric to try and sort out what I would do. Finally, I arrived at the following:




An eccentric/bearing carrier/vernier plate carrier combination thingumyjig that would give me the features I want. You can download a dxf CAD version here

I set off making the eccentric from some HRS rod (in fact, the left over bit that I had the gear wheel mounted on):





Some clean-up and a groove parted in as per plan. Not the best of finishes!:





Then I bandsawed the excess off, and mounted the workpiece 5mm off-center in the 4-jaw. Then I turned down the body (not really needed, but makes things easier in future) and drilled a hole through and bored a pocket for mounting a bearing:




With the body turned down, it was easy to mount the three-jaw chuck and bore the opposite bearing's pocket. If the body wasn't turned down, this would have meant using the 4-jaw to bore the pocket. It might have been quicker to do this... I thought I took a photo of the finished eccentric, but while downloading the photos from the camera to my PC I saw that I thought wrong :-[

I took measurements from the thus far assembled RT to determine the "center" hole position for the worm shaft "as if I was not going to use an eccentric". Then I added in the eccentric factor and the rotational position I wanted it to occupy for "worm engaged" - which should be the same as not using an eccentric. Some trigonometry calculations and I had the center coordinates for drilling and boring the hole in the RT base for the eccentric.
I marked that, and set up the base on the mill for drilling and boring. After center drilling, and drilling a 7mm hole, I switched to my biggest drill; a 19mm one:




I've used this drill bit in the lathe quite a bit, and the old Myford copes with it at medium back gear speed with some complaining. My 16mm drill press does not; it's lowest speed is too high. The mill utterly surprised me. On it's highest low range speed, it just turned that "little" drill bit - no complaints whatsoever - and at a good feed rate as well!

I still need to make or buy a boring head for the mill. The 19mm hole I had needed to be bored out to 30mm for the eccentric. I used the boring bar I made for the degree markings and another bit of HSS ground to what I thought would be appropriate angles to bore the hole out. Another surprise! I could go at a good depth of cut - in this photo I'm taking 2mm out of the diameter of the hole (1mm DOC) at a slow but steady down-feed:




The hole was bored to a good sliding fit for the eccentric.

To test everything - the moment of truth - I installed one bearing on the eccentric, and with an 8mm drill as "shaft" tested everything. Next two photos show both the locked and unlocked positions:








I'm happy ;D - the worm is dead on position in the locked position.

Regards, Arnold


----------



## SAM in LA

Arnold,

What an awesome job you are doing.

Perhaps I underestimated the $$ by quit a bit. :big:

SAM


----------



## Deanofid

Arnold, excellent work! The eccentric will be a nice addition.
You put two bearings in the eccentric housing, right? One in each end?



> I still need to make or buy a boring head for the mill.



Make it! Make it! About $5 in my money to make one. I can't imagine what a factory made
one would cost in your location. Take the cheap way out. You were going to spend the time
in the shop anyway, right? 

The one that Steve Campbell designed is very good, and could easily be adapted to your mill.
Just make it with a stub shaft on the end that goes toward the spindle, and hold it with a collet.
You can make it any diameter you like.

I'll put up a link for it if you want it.

I'd better let you finish your current project, I guess..
; )

Great work. I'm a fan!

Dean


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## wla421

I hope to be able to attain the level of skill that your guys here have..

Post plans for it, if you can once your finished.

George


----------



## arnoldb

Sam thanks ;D Our $ is pretty useless :big:

Thank you Dean ;D Yes - one bearing in each end, that is then preloaded from the shaft.
I've been eyeing Steve's boring head; in fact I have the plans sitting on my hard disk ;D I will most likely end up building it at a later stage - as you suggested with a 16mm shank and slightly bigger as my mill can handle bigger cutters. I'll also most likely adapt the feedscrew on it to work with a 0.5mm pitch thread; that will give nice metric settings for me with a 1mm full-size cut for every turn. But that's another project; RT first, then an engine, and most likely the boring head after that :big:

Thanks for checking in George . I'm also still learning; the more you practice the easier it gets Thm: I don't have a full blown set of plans, as a lot of the work was done by the seat of the pants for some spares and material I had on hand. I'll try and put together some plans once done  Most of the RT is loosely based on Dean's plans - here is a link to them and Dean's excellent build log. Have a look at the rest of Dean's builds as well; it's worth it! (Dean, I hope you don't mind)

I started on the rest of the worm shaft assembly today. First a quick mark-out on a piece of 8mm silver steel:






One end was turned down to 6mm for a length, and a space for thread-runout made with the rear parting tool, then I threaded the section left between the 6mm section and the run-out M8 - today I "cheated" and used a die instead of single-point turning the thread. Then I milled flats on the shaft; one on the 6mm section, another short one that will be the mounting spot for a collar, and the last flat for mounting the worm on:





Next I made the collar I mentioned above from a scrap of HRS rod. The small ridge on it's side is so that it will only engage on the inner race of the ball bearing it will be pressing up against:





I drilled two 2.5mm holes (tap size for M3) into the eccentric to carry the Zero/Vernier scale plate:





Then I cut a 12mm thick disc off some 40mm aluminium rod, faced it both sides and drilled a 16mm hole through it; this will become the Zero/Vernier plate. I then located it on the eccentric's bearing bore with a bit of 16mm rod and marked hole positions for drilling it's mounting holes by twirling the 2.5mm drill through the holes drilled in the eccentric. Then I drilled 3mm holes trough the plate on the marks, and counterbored the holes to 5.5mm to clear M3 cap screw heads. I also turned the end of a standard 8mm nut down to engage a bearing center like the collar I made earlier. Here is the collection of parts to make up the RT drive unit:





And all assembled:




The turned down M8 nut and a corresponding lock nut for it is hidden in the zero plate.

Then I marked and drilled a 3.2mm hole from the top of the RT base through into the eccentric hole, and then opened it up part way down to 4.2mm and tapped M5. A short bit of 3.2mm bronze brazing rod to locate in the groove and a cap screw (for now) to tighten it down:




I struggled to get the cap screw shown above into the hole... Until I realised the hole is M5 and the screw M6 :-[ - An M5 cap screw went in easily :big:

A bottom view with everything assembled - I had to move the worm wheel over about 1mm towards the end of the main shaft to get perfect engagement with the worm:





And an "operator's" view:





Does it work ? OOOH YES ;D. A light twist on the top screw, and the eccentric is loose to turn without coming out of the frame, and a twist on the vernier plate, and the worm engages with no perceptible backlash or disengages completely. And everything turns as smooth as silk and no lapping has been done yet ;D.

I think this project is about half-way done now... Fortunately we have a public holiday on Tuesday!

Regards, Arnold


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## Deanofid

Boy, Arnold, you really get down to business. That's a lot done at a single whack.
The whole spindle/worm/bearing/etc. assembly looks suspiciously like something that
came out of a machine shop. No surprise there! Very nice, indeed.

A small knurled brass finger nut would look nice in the hole for the eccentric lock.
Just a suggestion.



> (Dean, I hope you don't mind)



Not at all, and thank you for the kind mention in your thread... again!
We all like our name up in lights, no matter what we say.  ;D

Great thread, great build, great design work on your part, for sure!
BTW, this will make a fine video, when you've finished. We all like things that go 'round.

Dean


----------



## Artie

Deanofid  said:
			
		

> BTW, this will make a fine video, when you've finished. We all like things that go 'round.[/size]



Indeed it would! I for one would be watching... after seeing this evolve I looked at my RT yesterday while using it thinking..... I wish YOU were home grown.....

Excellent project mate...

Rob


----------



## SAM in LA

Arnold,

You do great work. :bow:

I understand that the eccentric is used to move the worm against the ring gear, what I don't understand is why not have the worm in a fixed position.

Boy, that last sentence confusses me and I wrote it. :big:

SAM


----------



## Artie

Hi Sam, I use mine in the free wheel position quite often, simply to move quickly to the next coordinate. Unlock, spin and relock. Otherwise its many many turns of the handle.

Sorry to jump in but I was onsite when you posted...


----------



## wla421

Arnold,

Not meaning to bust in on your thread..

Great work, as I said, hope to reach that level....

Dean, followed the link....and I got a bunch of info from your place.

Thanks for the link, and thanks for the detailed photos........great stuff.

George


----------



## SAM in LA

Artie,

Thanks. It now makes perfect sense.

SAM


----------



## arnoldb

Dean, thank you ;D. I was thinking of a knurled finger nut as well; swarf has a habit of filling up cap screws. But more in the lines of a blackened HRS one :big: - I save my brass for engines  I actually did take a short video clip of the hobbing in process, but it's pretty boring; maybe I must put a video together when done 

Rob, thanks mate ;D Most likely I would not have built it myself if it was more convenient to buy one, but like Dean mentioned - it's an experience in itself; and maybe for the better; I'm using my own-built bits & bobs a lot, and it's always nice to pick something up and think "Hey, I built this and it's useful!" I must say though; from all the bits I built so far, my collet chuck is by far my favourite!

Thank you Sam ;D - Like Rob explained (thanks mate ;D), it's usable for "quick" indexing. I still need to finish off some holes on the table that will allow me to do just that - sort of like a spin indexer. Another use of this "feature" would be like where I had to make up the wood block to hob the worm wheel; it could be used in a pinch to just mount the chuck, loosen the worm, and hob away; a bit of abuse, but then again, having built it on the cheap myself, I wouldn't hesitate too much to do just that. It's intended as very much a working tool in my arsenal - I'm just practicing with the finishes for building better engines :big:

George, thanks ;D - I don't mind anybody posting; this is not "My" thread; it's just one that I happened to start. Everybody's welcome to chime in for the greater good ;D

Today I made the hand wheel and adjustable scale; quite a bit of shop time, but came out OK, and the only interruption I had was a friend pitching with some meat to stock the freezer - that was most welcome!

Started off with a hunk of aluminium:





That I then turned down into the handwheel shape, with a boss on the front where the scale would locate on. Here it's all done and ready to part off:





Soon after starting the parting cut, I ran into chatter problems, but only on one section - the next photo shows the bit with chattering, while the rest of the groove is nice and smooth. I noticed while turning that there was a section in the aluminium rod that was harder or softer than the rest, and this is in that section:





To overcome the problem, I slowed the lathe down to the next lower speed, and also started a "double parting" cut; this particular parting cut would be pretty deep - from about 50mm diameter down to 6mm and a double parting makes things a lot easier, even if wasting some material:





I didn't want the finish on the part ruined when it dropped off on breaking through on the parting cut, so I shoved a slightly smaller rod mounted in the tailstock chuck into the hole when things were getting close:





After parting; not very neat on the cut side:





I cleaned up the untidy face by lightly gripping the part in the chuck with some soda can "protectors" and lightly facing off the offending bit. Then I mounted it on the RT for some final measurements. The face closest to the camera was the "bad" one above:





Next I started on the graduation wheel. Some 40mm aluminium rod with the end counter bored for a light push fit with the boss on the handwheel, and then just slightly cleaned up on the diameter, and with the parting tool a light groove turned to about 39mm diameter, so that I could knurl the projecting bit:




( :-[ I REALLY need to make a cleaner-looking and less sloppy knurling tool! )

After that, I parted the graduation wheel on length from the parent stock. Then I mounted the handwheel and graduation wheel together with a cap screw, and mounted the lot in the 3-jaw, protecting the handwheel bit with some more soda can strip. My 3-jaw's outside teeth are still pretty accurate (less than 1/2 thou run-out on most diameters) - so good enough for here without resorting to the 4-jaw and centering. Next I turned the excess off the diameter and most of the face of the graduation wheel:





The dividing head was still set up in the mill, so I transferred chuck and all to that. A quick check, and I needed the dividing plate with the 45 hole circle. Mounted that, and then set to marking the graduations. The one and 1/2 degree marks were easy; my DH has a 60 tooth worm, so for the "one's" its "start at zero; graduate, 12 full turns, graduate; repeat". To get the halves, just crank six turns and repeat as for the tens. For the 0.1 degree marks, it was a bit more work; 1 1/5 turns per mark - but a LOT quicker than the 10s and 5s on the main table :big: - Here I took a break from counting and marking the 0.1s to take a photo - My mind was starting to wander so some timeout to restore focus after a careful note of current settings:





The handwheel still needed drilling and threading for a grub screw to mount it on the shaft. Here I'm using the old trick of using a flat plate (old feeler gauge plate) to find the center on the circumference to drill:




This method can be pretty accurate, but there are caveats...
 In many descriptions of this method, a rule is used to do this. I don't like using a rule, as the engraved markings on a rule can have a negative effect. (anyway, good rules costs money  )
 One needs to check with the drill bit rotated to a couple of different angles and judge the "average" level.
 A new spot on the plate should be selected for every test.
 Don't move the workpiece while the drill press is under pressure; lift away the drill bit, move the workpiece or rotate the chuck and retry.
 The smaller the diameter of the workpiece, the more accurate this method becomes (if you choose new bits on the plate for pressing down on, and don't use a rule where the engraved markings can cause a problem, and check with the chuck rotated a couple of times).
 Gravity does have an influence if you're working with light pressures; try and have the plate balanced on the workpiece before starting.

Getting ready to knurl the handwheel - simply fit to the collet chuck with a cap screw from the back, and a nut pulling the wheel up to the chuck face. My biggest knurling job to date on a VERY "iffy" setup... This is at the extreme capacity of my rough knurling tool, and to boot, a knurling job wider than the knurling wheels... There's a LOT of sideways slop in that tool :-[ :




LOTS of coolant/lubrication from the synthetic soluble cutting oil squirt bottle (mostly to wash away any swarf build up) and the job was a good 'un; not perfect, but entirely acceptable for me for now.

Next up I turned a shaft from 6mm silver steel, threaded M5 male one end and M5 female on the other (to accept an M5 cap screw), roughly turned, and finished with a file & emery a handle and drilled and counterbored it to take said cap screw and shaft, and parted it off 0.2mm shorter than the shaft. A bit of stiff spring salvaged from an old printer, shortened with the Dremel and ground down to length on the bench grinder, a couple of washers, a grub screw, and a short length of brazing rod all resulted in today's collection of parts:





And duly assembled as a handwheel with zero-able scale:




I'm quite happy; that lot came together rather well. The scale takes a "nice" amount of effort to adjust and does not slip on the handwheel at all.

Making the vernier scale on that zero collar is going to be a bit of a challenge, but I have some ideas around that  I'll see what odds 'n ends I can finish during the week, but that particular job has to wait for the weekend.

Regards, Arnold


----------



## SAM in LA

Arnold,

Dang Dude, don't you ever sleep?

Looking good.

SAM


----------



## Deanofid

You sure do a fine write up, Arnold. Good pics, too. These parts turned out great!
And that knurler, whatever you say about it, looks like it does exactly what it's supposed to.

Dean


----------



## wizardofwood

Arnold
that is looking lekker hey.
A beautiful piece of work.


----------



## arnoldb

Thanks again Sam ;D - I like my sleep though :big:. Tonight I'm taking a break and attending to some other matters 

Dean, thank you very much ;D. Its partly your fault though; you "pushed" me into it trying to improve my documentation :big: - Thank YOU!

 ;D Baie Dankie Wiz. .... "Lekker" :big: - one of those Afrikaans words that encompasses so many English ones in just a few letters ;D - yes it is lekker!

Kind regards, Arnold


----------



## Twmaster

Arnold, I'm a bit late to your party!

What a magnificent job thus far. I'm eager to see how you finish the table.

I stumbled upon a worm gear set out of an old sewing machine today. Your project has me thinking!


----------



## arnoldb

Thanks very much Mike ;D - I saw your salvaged spares 

I've been putting off further work on the table while waiting for a T-slot cutter I ordered 3 weeks ago, and to do some calculations for making the vernier markings.
The cutter arrived today, and the calculations are sorted out for the vernier markings. While picking up the cutter, I also added two circlip pliers to my arsenal - so that I can get around to adjusting my mill's spindle bearings which seems to be a bit loose...

Regards, Arnold


----------



## SBWHART

Real nice work Arnold

Good luck with the T sloter they can be tricky beasts to use, rough the slot out first with an end mill take it deeper than you will take the sloter if you try cutting across the full face of the sloter it will break, don't ask me how I know :

Stew


----------



## arnoldb

Thanks Stew ;D. I'll mill the slots slightly deeper at the bottom - I think about 0.25mm should do it.

Today I faffed around with the vernier collar and some number punches - and ended with a mixed bag of results...

Having done the calculations for the vernier collar, I set out to make a template to mark it off it from. I cheated a bit, and instead of manually laying out the template with a pair of compasses, I did it with CAD and printed it. I know my old HP laserjet 6L prints very nice and accurate circles from QCAD, so no worries there.

Next I cut a "round" piece of plate from an old computer casing - here it is roughed out with some tin snips:




I just took it to the bench grinder to get it nice and round and without sharp edges - no finesse with a file, as this is a quick 'n dirty...

I used the compass to cut out the template from the printed page as well; I keep my compass fairly sharp, so it does cut paper albeit a bit crudely. At one point, I made a booboo and let the center slip, but not too much of a concern:





The paper template needed to be glued to the round plate... I didn't have any suitable glue on hand, so I used an ancient can of clear lacquer I've had for years (12 to be precise!) to spray a thick coating on the plate, and then stuck the paper template to it while the paint was still wet. Just for the heck of it, I ran another coat of lacquer over the top:




I didn't bother cleaning my hands so there are oily smudges all over the paper :-[

After leaving that lot in the sun for about 20 minutes to dry, I centered and clamped it on the drill press. Thoroughly. I needed to drill a 16mm hole through the center, and plate is a bugger on break-through:





All drilled; no fuss or drama :





Next I turned a mandrel from some 20mm aluminium rod - to mount the vernier plate on one side, and a 16mm shank to grip in my collet chuck on the other side, with the template between the collet nose and the shoulder on the mandrel - here the vernier plate is already mounted on the mandrel:





I fully intended to take photos of how I clamped this lot together on the collet chuck... and promptly forgot to take any :-[. I mounted the collet chuck on the lathe, pushed the mandrel through the plate and into the collet in the chuck, and used the tailstock to press on the mandrel while tightening the collet closer. This kept the plate tight between the shoulder on the mandrel and the collet nose; I didn't want it to rotate later on.

Then I took the collet chuck with its contents off the lathe, and screwed it to the dividing head still mounted on the mill. For this job, the dividing head is useless for making the graduations (that's why all the fuss with a template) - but is useful as a handy mounting to make things go around.
Needing a way to index off the template, I taped my scriber securely to the magnetic base arm with some insulation tape, and set the lot up on the mill - with the scriber point very nearly, but not quite, touching the template:





Then I milled the markings; I made the template to conveniently show the lengths, so this was pretty much a no-brainer to do - except to get the scribe point as accurately on the line for each graduation as possible. I ended up with this:





Quite proud of my achievement in making a vernier scale, I put it on the RT and tried it out.... oh: oh: oh: :wall:
The scale is good - for working to 0.01 degrees. Those short 0.005 degree markings are completely useless... Had I stopped earlier this week and really thought things through, I would have realised it... The handwheel collar does not have 0.05 degree marks to align the vernier marks to in the 1/10th scale I made it at. To get the 0.005 vernier scale to work, I either have to put on the 0.05 marks on the handwheel collar, or I have to stretch the vernier makings through 18 divisions on the handwheel...

At that point I didn't know whether to kick my own butt, or to cry. Instead I ended up having a good laugh at myself for being too clever for my own good, and I'll leave things as is. The small half-marks on the vernier plate can serve as a future reminder that it's possible to do some nice work off a crude template and setup, that I need to think things through more clearly, and that sometimes I just need to laugh at myself. If the marks bother me in future, I'll make a new vernier plate. With my tests, I found that it would in any case be very difficult to index to 0.005 degrees using the 72 tooth gear wheel on this size. The 0.01 degree marks are good to use, and when I set out on this project, that was what I had in mind anyway.

Next up, I marked my set of 3mm (1/8") number punches with a permanent marker. The numbers on the punches are oriented so that when the punch is held upright, and I can read the number, the punch is the correct way around to stamp the number properly:





What, no 9 ??? - here it is; it's on the "other" side of the 6 punch :





And another crude jig to stamp the numbers. A slot milled through the face of some scrap HRS, and mounted on the magnetic base, mounted on my steel workbench serves as a punch guide. A small drill vise clamped to the table to hold down the workpiece, and I aligned the work with the end of the fixed jaw in the vise to set the depth:




It worked sort of OK - Ideally I should have stamped the numbers on the workpieces while they were all still mounted in the lathe chucks, but I'd rather take some slight misalignment on the numbering than damage my chucks and so forth by hammering on work items in them.

Result of some stamping on the table itself:




The two 3's on the 330 looks badly formed, but they are OK; I forgot to rub a dirty finger over them to fill up the recesses to improve contrast, and the lighting is playing havoc.

Some more of the numbering:




By no means perfect, but it will have to do for now.

I hope to get some more done tomorrow - thanks for reading along.

Regards, Arnold


----------



## SAM in LA

Arnold,

I would say that you have done a very professional job on your rotating table.

The $'s value keeps increasing. ;D

SAM


----------



## tel

Beautiful work Arnold.


----------



## Deanofid

Yes, it IS looking very good. You show us some imagination in your line marking setup, too, Arnold.
Your numbers look good, to me.
I still don't have numerals on mine. I worry too much about double strikes, and fear of goofing up 
permanent markings has turned me into a wimp. Someday I'll make a proper stamp punching guide, 
and let my hammer do some talking. 

You're really giving us a good show. Thanks!

Dean


----------



## zeeprogrammer

Deanofid  said:
			
		

> You're really giving us a good show.



Same from me. Thanks Arnold.


----------



## bearcar1

Good heavens man, and you're doing this on the fly? My hat is off to you, that is some fabulous looking work with some equally fabulous results. Well done! Thm:

BC1
Jim


----------



## BobWarfield

Arnold, thanks for letting us look over your shoulder. This has to be one of the most impressive projects I've seen in quite some time.

Best,

BW


----------



## Maryak

Arnold,

Or should I say Vern(ier). ;D

Absolutely wonderful, gobsmacking stuff, HATS OFF to you. :bow: :bow: :bow:

Best Regards
Bob


----------



## Twmaster

Arnold, like the others I cannot tell you how awesome I think your home made R/T is. Magnificent.

I also really like that stamp holder you've made. Good excuse to retire my Chinese stand and relegate it to stamping work down the pike.


----------



## arnoldb

Sam, Tel, Dean, Zee, Both Bobs and Mike, thank you all very much for your comments - I feel slightly overwhelmed! ;D

Dean, I practiced a bit first on some scraps. Funny thing though; it was easier to get better looking numbers on the cast iron than on the aluminium; maybe because it has a bigger diameter. Oh yes - one letter; one knock! I have one "slightly doubled" 2 from a double knock :-[

Mike, I nearly used the drill stand visible next to the punching setup - but I just couldn't. It's a good quality drill stand and was my only "drill press" for many years, and has an aluminium base, so I don't think it will stand up to hammering. As to the "Chinese" stand you have, I'd be hesitant as well - I'm not entirely sure it will stand hammering on it, but on the other hand, they are so cheap as to be nearly "consumables".

Well, not much to report for today; I spent most of the day getting to my mill's spindle (I finally could after getting those circlip pliers!), disassembling it, cleaning everything thoroughly, and re-assembling and adjusting the bearing pre-tension. No photos of the process though; my hands were too dirty to use the camera :big:. 

And boy-oh-boy, what have I been missing out on! Once adjusted and re-assembled, I played around with bits of scrap to see how much of a difference the cleaning and adjustments made, and I was totally surprised! MUCH better cuts, and MUCH improved finishes, even when cranking at a good clip. A difference between night and day.

One of the scraps of HRS I practiced on became the two locking clamps for the RT. After testing the flycutter on some scrap I decided it was worthwhile to jump in and fully flatten and square up the side on which the RT will be used in the vertical position. Standing on edge it was close to, but not fully square, and I ended up using a 0.05mm feeler gauge plate to shim it to clamp it down nice and square. More "no photos", but I took a short video clip while starting a flycut on the surface. If you are prone to seasickness, please do take some Dramamine or ginger first; I was holding the camera in my right hand and cranking the table with my left hand:
http://www.youtube.com/v/UywqSxgYfik

Then I drilled and tapped the top of the base M6 to mount the locking clamps - here is a view of the flycut face and one of the clamps mounted; the other one is on the opposite corner of the table:






So, not much to show, but a whole lot gained, for today's bit so I'm confident that I can now start on the T slots in the table for the next step 

Regards, Arnold


----------



## tel

You won't have any trouble with the Tee slots Arnold, I cut the ones on the little 3" I made with a crude, home made cutter and they came out just fine.


----------



## Deanofid

Ditto to what Tel said, Arnold.
I do not find T slots difficult. Mine were cut with a cutter I made from drill rod, and my table is HRS.






With a factory cutter in CI, you should have no trouble. Just do as someone mentioned, and mill the 
"start slot" a little deeper than the T-slots will be. 

The fly cut side looks very nice!

Dean


----------



## putputman

Dean, when you guys talk about a "T slot" cutter, are you using a standard "woodruff keyway" cutter or do they make actual t-slot cutters.


----------



## Deanofid

Hi Arv;
It's a standard cutter. Depending on whose catalog you look at, called a T-slot cutter, or maybe just a slot cutter. Usually called just what you want, though. T-slot cutter.

Here's a link. Check toward the bottom of the page:
http://www.use-enco.com/CGI/INPDFF?PMPAGE=119&PMITEM=367-3010

Are you going to make something fun?

Dean


----------



## RichD

Arnold,
I've got to tell you...Have you ever picked up a book and couldn't put it down? 

I'm sort of new around here, and I noticed this thread awhile back but never took the time to read it. I finally started reading this around 8pm California time last night but couldn't finish due to needing some sleep. After my 12hr shift today and obligatory wifey time I headed straight back to this thread because I guess my learning curve was still hungry for more.

Thanks so much for the presentation and details.

I have no plans to build a rotary table but the methods and pre-planning you documented will serve many of us for the myriad oddball situations we'll come up against as this hobby unfolds.

So...How do you plan to stop the BP oil well leak? Hope to see that thread soon :bow:

Regards,
Rich


----------



## tel

putputman  said:
			
		

> Dean, when you guys talk about a "T slot" cutter, are you using a standard "woodruff keyway" cutter or do they make actual t-slot cutters.



As Dean said Arv, they are a purpose made cutter. A true Woodruff cutter won't work 'cos they have a little projection with a centre in it at the bottom. The reason? They (w/r cutters) are still classified as a tool for the horizontal mill and have the centre for outboard support.


----------



## mklotz

Typical T-slot cutter...

http://www.use-enco.com/CGI/INSRIT?PMAKA=367-3010&PMPXNO=947084&PARTPG=INLMK3


----------



## arnoldb

Tel, thanks ;D . I like that little 'un you made :bow:
Thanks Dean ;D - that flycut is the best finish I have to date achieved on the HRS without resorting to files & emery!

Rich, thank you  ; welcome to HMEM and you're welcome  I don't know about that oil leak though; my first thoughts was a ton of explosive dropped down there to blow those shafts shut, but that may not be a good idea ???

Arv, Like Dean & Tel said.. and the one Marv linked to looks nearly identical to the one I have, except mine is slightly smaller and metric.

I'll wait till next weekend to do the T-slots; evenings are a bit short, and I'd like to finish them off in one session with a fresh start. So things on the build will be a bit quiet this week...

Regards, Arnold


----------



## arnoldb

Well, I have spent zero time in the shop for the last two days. This afternoon after work an urge to cut some metal overwhelmed me.

I decided to make the thumb screw to operate/retain the eccentric. Originally I was going to make it from some scrap HRS bar, but I decided to make it match the handwheel assembly, and opted for an aluminium unit, with a length of 5mm threaded rod screwed and loctited in:





The thumb screw went so quickly that I wasn't satisfied... I had an itch and it needed scratching.

So I decided to start setting up the table for machining the T slots. I've thought through and visualized the machining steps for cutting these slots over and over in my head, and nothing seemed out of whack. First I placed the rotary table roughly in the spot I wanted it for machining, and cranked the mill to roughly center it below the spindle. I took careful note of the direction I was moving the handwheels and zero'd those.  Then I cleaned the mill table thoroughly, put a piece of paper below the RT, and with a bit of 16mm silver steel (to match the deep hole in the RT center) gripped in the mill's collet chuck , I lowered the quill to center the RT and locked the quill:





With the RT held on center from the mill spindle, I then used an engineer's square against the side of the RT base I flycut in a previous post to get the RT base square to the mill table - flipping the square over while checking, as well as checking from both edges of the mill table. This is not a very precise method - it would have been better to use a DTI to test, but I felt this was one of those jobs where "good enough" is, well, good enough. T-nuts are not all that precise... , especially if I made them!

Then I clamped the RT base down solidly on all sides, set the RT and it's handwheel to zero degrees, locked the RT table with it's own clamps, and as an added safety precaution, added an additional clamp on top of the table. I don't want anything to budge. I also scribbled down all the necessary readings, directions of feed, and a couple of things to check regularly while machining on a bit of paper:





Maybe I should have stopped there, but the temptation was too big. I decided to go for the first cut... a new 8 mm slot mill, mill set to it's lowest high speed range, 2.5mm depth of cut, and at the start something felt wrong; way too much vibration, and the milling bit wasn't really cutting well... Normally I slow down when this happens, but I had a "gut feeling" that in this instance I was going too slow... I've started to trust that "gut feeling". So, next speed up, I started feeding slowly, and things went much better. Then I started cranking the handle a bit more quickly, and everything came together; I had nicely shaped chips coming off and no heat that I could detect ;D The first pass done and with a nice finish as well:





After 3 more passes at 2.5mm DOC and a last pass at 1.8mm DOC, I was down to depth ;D:





The swarf magnets and my tummy was insisting at that point to have dinner, so I stopped there, with the needed settings added to my list of notes.

Regards, Arnold


----------



## SAM in LA

Arnold,

Its to bad there is not a "Tool of the Month" catagory.

SAM


----------



## zeeprogrammer

Nice Arnold. Sounds like it went well (or even better than you expected)...congratulations.

Are you sure you're not just showing us a bought thumb screw? ;D


----------



## Noitoen

SAM in LA  said:
			
		

> Arnold,
> Its to bad there is not a "Tool of the Month" catagory.



For that same reason it was changed to "Project of the Month"


----------



## arnoldb

Thank you very much Sam; I consider that an extreme compliment ;D. I'm not sharing my build to win an award though; I'm sharing it in the hope that someone might find useful bits in it, just like I have found a LOT of useful information from other people's posts - it's the best way I can think of returning the favour.

Carl, thank you ;D - Yes, it did go well; much better than expected! - Thank you! OK, I'll admit it... :-[ I bought the thumb screw from a local company called AMESS. I like supporting the underdogs, so I gave this upstart company a try; the service level can definitely be improved, but the rates were reasonable; apparently they use scrap to make bits 'n pieces. The name reminds me a bit of my own workshop... When I asked, the proprietor told me the name comes from "Arnold's Model Engineering Supply Services". Not many Arnolds involved in engineering here in Namibia though... AMESS's marketing strategy and business sense seems to be a bit of a mess though... 

Helder, thanks for checking in 

I rushed home from work this afternoon! And finished milling out the centers of the T-slots - without rushing. I followed the check list I made and the readings I jotted down to the last drop - including checking between each slot that nothing had come loose from vibration anywhere. On cutting the third slot, I had a bit of a scare; at one point the milling sounds started sounding different from the previous slots - and the feel on the handwheel was "less positive" for lack of a more "tactile" description - so I punched the emergency stop, and checked everything through again. I found that the drawbar had worked slightly loose. I try not to over tighten the drawbar on my mill's MT4 spindle; well, I'd under-tightened it, and the collet chuck had come loose in the spindle... Fortunately I caught the problem in time, and just re-tightened the drawbar; I could not even see any abnormality to the slot caused by the chuck coming loose, so I carried on. The result:





Finishing the three slots left after yesterday's one took me less than 45 minutes to do, and I was feeling both alert and relaxed at that point, so I decided to push on. I changed to the T-slot cutter. To find zero on the Z axis after changing the cutter, I unlocked the feed wheel, and used the drilling arms to lightly pull down the quill to the point where the cutter touched a piece of paper on the RT. Then, without locking the Z feed wheel, I cranked it to zero (in down-feed direction to compensate for some backlash) and then locked it on, and used it to reverse the quill. My mill's Z feed is not zero-able otherwise... I guess I'll be making another zero-able handwheel in future!:





My T-slot cutter's diameter is too small for my exact requirements, and it also cuts a slightly too high undercut for the slots. I wanted the slots on the RT to match my Myford's slots, and I had to have a compromise. Well, if I made the cutter myself that would not have been necessary, but with the bought one it was. With the smaller cutter diameter, I had to offset the cuts to get enough undercut on both sides, rather than finishing in one pass.
For one pass, things were A-OK; I could feed in on the Y axis and do the pass with a nice conventional cut. The opposite side was a problem; I would be climb-milling. I dug in with the first cut, and to try to get a conventional cut on the return on the opposite side, I tried back-feeding on Y while at the deep end of the cut on X. Things just did not feel right, and the cutter was "complaining"... So I reversed the Y back-feed, brought the cutter out on X and tried the climb cut with two passes on Y. It worked with a slow and steady feed ;D - and I finished the first T-Slot:





The other three T-slots were formalities, except the last one... I had to keep telling myself to "Keep it steady; don't rush; pay attention" on the last cut; it seemed to take forever but was at the same speed as the others!
Everything came out well though, and this is the result (with the "shop bought" thumb screw added  ):









For those who swallowed the obligatory Dramamine or ate a bit of ginger: 
[ame]http://www.youtube.com/watch?v=7PitwaclZT4[/ame]

The RT is now pretty much operational; I will still finish it with a bit of lapping like Dean demonstrated in his build, as well as add a couple of other "touches". In fact, I'm pretty pleased with the outcome up to now, and with not much left to go wrong, I broke out the VSOB and had a good glass of Chivas on the rocks to celebrate ;D - My apologies if this post was a bit "under the influence" :-[

The "chuck adapter" for the RT to take my lathe chucks will still be quite a bit of work though!

Regards, Arnold


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## Twmaster

Arnold. That is magnificent. Bravo on a truly inspiring piece of work!


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## Shopguy

Arnold
That sir, is one impressive bit of work. I've followed along, with interest, from the beginning and I must say the whole project has been an education in and of itself.
Regards
Ernie J


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## zeeprogrammer

I'd be happy to do business with AMESS.
I wish it wasn't so far away. Postage is a killer.

Very nice job. An inspiration really to people like me. I wouldn't have considered the idea that someone could make something like that. To the point that I ask myself sometimes why I bought some of these tools...I could've made them. You make it look do-able.

Again...very nice. Thanks for taking the time to post the road and let us travel with you.


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## putputman

Great looking RT Arnold. You have to be proud of that project. :bow: :bow:

Time kind of slips by. I lost track of this post after I questioned the T-slot cutter. Thanks Dean, Tel, Marv, & Arnold for your answers. The reason I asked is I have a good assortment of Woodruf cutters that I thought could be used for cutting T-slots. I wasn't aware that there were special cutters for T-slots. I see they have deeper chip clearances and side clearance as well.

Dean, I haven't got any special project for these cutters at this time. Just curious.


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## seagar

Thank you for showing us a great build,you should be proud of your excelent work.
If I could build something like that ,I would chrome it and put it in a show case, LOL. :bow: :bow:

Ian seagar)


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## Deanofid

Everything came up roses, Arnold! Those slots look just like the factory boys do it, and the worm
eccentric is a really neat thing. Such a good job. I really like it!

That little AMESS outfit does alright, too. They should go into business.

Thanks for another great post.

Dean


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## Hamstn

Congratulations Arnold. Thanks for the great thread. I inspired me to get going on mine. Don't take this the wrong way it also discouraged a little due to your patients on getting a super fit and finish, something I need to work on.


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## Maryak

Arnold,

What a great accessory you are making. :bow:

It's almost a pity to get it dirty from use..........................................ALMOST :

I am sure you will have many rotational successes from this little beauty.

Best Regards
Bob


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## arnoldb

Mike, Ernie, thanks very much guys ;D

Carl, thank you . As to making something like this, it's been done a lot in years gone by. A lot of the theory that I apply I gained from reading books by past masters; now I'm starting to put that theory into practise. It's sort of a dying craft to make one's own tools, but I'm willing to try and help preserve the craft for as long as I can.

Arv, Ian; Thank you ;D Yes, I am well pleased with the result; but this one is not going to get shoved on a shelf  - It now has to start returning on the investment.

Thanks Dean ;D - The T-slots are not quite as well made as my old Myford's, but, dare I say it.... came out to a much better finish than my mill's.

Hamstn, thank you ;D. I won't take it wrong. A year ago I could never dream of getting fits and finishes like these. Then, like you now, I also felt somewhat discouraged and in awe to see people producing good work. There is only one way to improve, and that is to try and do as good a job one can on even the simplest of projects; rather than buy things like toolmakers clamps, die holders and so on just take some time and make them - the little extra touches needed start to become second nature and the more one machines, the better things get  So hang in there and just give it your best shot, and over time it will all come together for you! Oh - and another little lesson I learnt; When - not if - things go wrong, just stop a bit and think about it, and figure out a positive way to attack the problem - a positive attitude is already half the job done Thm:

Bob, thank you very much ;D - believe me, its going to get dirty though - I have a lot of builds in the pipeline 

Kind regards, Arnold


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## SAM in LA

Arnold,

AMESS looks to me to be a rising star in the Model Engineering field.

Keep up the good work.

Your table makes my cheap import table look, well, cheap.

SAM


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## RobWilson

Hi Arnold 


Top job mate :bow: :bow: :bow: :bow: now what you going to make next ? stickpoke stickpoke stickpoke:big: :big: :big:


Regards Rob


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## Philjoe5

Arnold,
Fantastic job. I've truly enjoyed following along. Thanks for documenting this great project.  :bow: :bow:

Cheers,
Phil


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## Blogwitch

Arnold,

Even though I haven't commented before now, I have been following along, and I have to agree with all the good comments that have been made.

Very well done indeed. You have made a major piece of tooling all by your own hard work and perseverance.

Sit back for a bit, have a brew, and get used to that big grin you must have, because surely, you will have a lot more in the future if you carry on the way you are going.

A great post all round.


John


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## arnoldb

Sam, thank you very much ;D

Rob, thanks mate ;D. I'll finish the lathe chuck adapter for the table first. Next project will be a bit smaller and a bit less demanding ;D

Thanks Phil ;D I don't know about "great", but it sure was a lot of fun!

John, that is high praise coming from you - thank you very much indeed. You have the grin and brew spot-on; exactly what I'm doing tonight. As to following along, I happened to notice at one point. I must say though, I am pleasantly surprised at how many reads this thread received!

Kind regards, Arnold


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## Florian

Superb! Just Superb! :bow:

Whats going to be your next project? 
Selfmade Boring and facing tool? ;D

Cheers Florian


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## RichD

Looks Great Arnold.
Thanks again for sharing.
Rich


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## joe d

Arnold:

That sure turned out great :bow: :bow: I enjoyed following along, and look forward to your next project!

Cheers, Joe


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## SBWHART

I was with you all the way Arnold great bit of work and well shown.

Stew


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## swarfmaker

Congrats on (yet another) item well done. :bow: :bow:
Proud of you
Dad


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## ksouers

Congratulations Arnold.

Very well done and great documentation of the process. Now I just have to get off my duff and start my own.

That is truly an inspiration to anyone wanting to build their own tools.


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## arnoldb

Florian, thanks ;D - my next project is an engine - I haven't decided which one yet though. Something simple to take a bit of a break  Steve Campbell's boring tool is a definite on my list though  - You can have a look at Dean's version and get the plans here

Rich, Joe, Stew - Thank you guys ;D

Dad - Thank you very very much indeed! Means a lot to me. Chat to you on Sunday evening ;D

Thanks Kevin ;D - I think I have a larger collection of home brew tooling than engines by now : - maybe I'm fortunate that even the "cheap & cheerful Asian tooling" is sometimes difficult to get and expensive by the time it ends up with me - so I'm forced to make do and have fun in the process :big:


While the RT is pretty much finished (just needs a tear-down for cleaning, a quick lap of the table to the base with some grinding paste, and (maybe) some paint), I do need an adapter to mount my lathe chucks on it. This is not much of a build; it must just be made accurately, and easy to mount on center on the RT (where I'll most likely use it most of the time), but also off-center if need be, as I have some ideas of machining operations where this might be very beneficial.

My raw materials are running a bit low, but I have ~5 meters of 60x10mm flat bar left (I had to buy 6m for the RT base :) - so a bit of that is fine for the chuck adapter base. I'm pretty much out of ideal round bar for making the nose for my screw-on chucks; the only bit I could find is not quite as large in diameter as I would have liked, but it will have to do for now. If it is a problem in future, I'll make a new adapter.

The bit of flat bar with 6mm slots milled in it for clamping to the RT, centered in the 4-jaw for facing and boring a hole in it:





It's chucked with the jaw edges - not because the slots would interfere, but to be able to use the lower parts of the jaws to keep it flat on the surface of the steps on the jaws. 

I then faced the plate, and drilled and bored a 25mm hole in it, with a good chamfer on the face edge of the hole. Then I turned the bit of rod I have to _just_ clean off the crud on the OD, and then turned a section on the front down to match the hole bored in the plate with a fairly close under-size fit (0.02mm / 0.0005" smaller) I could have gone for a press fit, but rather chose to silver solder this joint - hence the bit of "looseness":




I didn't go for nice finishes on this; the visible parts will be turned down further and the rough finish at the plate end will help wick the silver solder through the joint.

Then I fluxed up both pieces, and placed two bits of silver solder on the plate. The plate is suspended on two bits of fire brick, so that I can heat the joint from the bottom with the oxy-butane torch; with the solder on top and the heat coming from the bottom, the solder would want to flow down into the joint - towards the flame:





These are big bits of metal for my small torch, so I set my little butane "plumber's" torch to heat the top bit of rod to get some heat into it without the flame directly playing on the flux, and played the oxy-butane torch with a good blue flame on the bottom. It still took about 3 minutes for the flux to start to flow, and another minute after that for things to reach enough heat for the solder to melt and flow. The rod bit dropped down when the solder melted, with nearly no solder appearing at any of the edges of the joints, so I used just about the right amount ;D :




I couldn't be bothered to pickle that lot after soldering; when it cooled down to black, I just shoved it under a running garden tap to cool down. Very little to clean up, and most surfaces will be machined again...

Hopefully I can finish this tomorrow 

Regards, Arnold


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## arnoldb

Well, the weekend's gone and there are still loose ends. Fortunately the chuck adapter is done.

I started by turning a ring from some scrap HRS rod - for a light push fit into the "register" hole I bored in the RT's table. Here, it's done and I'm about to part it off:





The ring's purpose will become clear later...

Then I chucked the assembly I made yesterday in the 4-jaw, and roughly centered it - checking that I would need to remove a minimum of metal from the bottom to face it. I then faced it, drilled and reamed a 12mm hole through the center, and bored out a section to fit the ring made earlier, but with the ring a slightly tighter push fit; easily removable, but not inclined to fall out on its own:





Next I cheated a bit. The workpiece has to be accurately turned around and re-mounted to keep both concentricity and axial alignment to the mounting face. I know that my lathe's tailstock and drill chuck is VERY close to perfect alignment with the spindle - less than 0.005mm out on offset, and extremely accurate in line - I can't even measure this. So instead of setting the job up in the 4-jaw and centering it, I mounted the face plate, and with a bit of 12mm silver steel chucked in the tailstock, used it to mount the workpiece to the face plate. No mess, no fuss, and as well aligned as I could have made it with the 4-jaw; just a LOT quicker ;D :





Then I proceeded to face this side of the mounting as well; not really needed, but does look neater, and then turned a spindle nose replica of my lathe on the front section, leaving a bit of clearance so that a mounted chuck will not come into contact with cap screws used for mounting the adapter to the table. I didn't take photos of the process, as I thought I'd just link to a similar adapter I made when I built my collet chuck Turns out, back then I forgot to take some photos :-[ Next time, I won't forget.

This was the end result of the operations:





Just for fun, I put the RT to use to clean up the ugly ends of the adapter:




I'm very glad I did this trial run; it uncovered some hiccups - easily addressed once I do a strip and re-assembly of the RT. For one, the pre-load on the bearing is not enough as it is assembled now. I had the grub screws holding the worm and the wheel come loose from vibration, so at next assembly, I'll use some thread locker on them.

This is what the lot looks like with my 3-jaw chuck mounted on it:





I was wondering how I am going to keep my chucks from unscrewing from the adapter while in use, and I already had a whacky idea drawn up - but I'm not going to use it... Seeing everything assembled like this, a far simpler idea struck me; it will be easy to make "clamps" that can be mounted in the unoccupied T-slots on the table that will both lock the chuck as well as add some additional rigidity :

Regards, Arnold


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## Deanofid

That's a good, sturdy looking outfit, all said and done. Looks great too.
That 'new tool' smell should last a long time, since you installed it yourself!

You're quite a builder, Arnold. I'll bet we'll be seeing this one a lot in your future threads.

Dean


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## RichD

That's a great looking setup. Where's the stepper motor and keypad? :big:
Rich


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## SBWHART

Lovely neat job Arnold

Stew

Just had a thought your face plate will fit on their, how about your ER collet adaptor ?.

Stew


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## BenPeake

Hi Arnold,

Love the work you have done with the RT. I have attempted making a few tools around the workshop, but nothing like this! It must be immensely satisfying to use it! Much more fun than using a bought RT. Congratulations on a fine project. My favorite parts was the gear cutting. Thanks for posting,

Ben


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## metalmad

that is just so nice its not funny


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## arnoldb

Dean, Thank you ;D - I'm not going to bet against you 

Thanks Rich ;D - No CNC in my shop  - I do machining to get away from computers! Well, there is a power feed for the mill in the pipeline, and maybe a small home-brew cnc "engraving" machine to make name plates and such - very distant though...

Stew, thanks mate ;D

Thank you Ben ;D Like I mentioned; there's a couple of nigglys to sort out with it still, but the bit I've used it, it is very nice. I also enjoyed the gear cutting immensely - one of my future projects will require making an internal gear; that should be fun as well ;D

Thanks metalmad ;D - maybe not funny, but it sure was a lot of fun 

The final bits will now have to wait for coming weekend; my entire week's evenings are pre-booked. Hopefully I can finish everything completely on Saturday, so that I can start on an engine for a change!

Regards, Arnold


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## arnoldb

Well, the RT is finally done... (for now :big

I first lapped it with some valve grinding compound after some disassembly - here I just applied the compound to the raised edges on the table:





The next two photos show the progress of lapping after about 10 minutes of vigorously turning the table through turns clockwise and anti-clockwise. I just rubbed away the grinding pate with a finger to check.. :









Notice how the inner face ring on the table is less affected than the outer face ring... ; I expected this, as my lathe faces slightly concave (by design), and with the facing operations on both the base plate and the table base, this effect was doubled.

After another bit of lapping (20 more minutes), and a very thorough clean-up (ending in the kitchen sink with dish-washing liquid), this is what the base top looked like:




Maybe I should have done a bit more lapping, but this "felt" OK.

One last machining job, that should have been completed earlier (I forgot :-[) was to make an M6 threaded hole in the "bottom" of the main shaft. I chose M6, as the tapping drill for it is 5mm; this is one of those convenient sizes where you can shove an M5 bolt through the hole to clamp something down from the top of the RT table, as well as use an M6 bolt to "press out" a working piece from the bottom of the RT if something came stuck in the RT shaft. Here I'm drilling the 5mm hole on the drill press:




The shaft already had a center-hole drilled in it from the previous machining - so just picked that up in the drill press.

Next I thoroughly cleaned the bearing and use some good quality "LE" grease that my Dad (Swarfmaker) donated to me to lubricate the bearing - thus far, it has been running on oil.... :





Then I applied copious amounts of way-oil (the same I use for my lathe ways; a sticky thick oil) to the table, and started assembling the RT once again:





During assembly, I used medium strength thread retainer on all screws and the worm and driver shaft. This should prevent the screws from loosening like I found from first use, but be "easily" enough removable to disassemble the RT for maintenance. I can kick my own butt for not adding a pressure forced oil-hole in the table top to "inject" oil for lubrication; hence the finally done "for now" start of the post. I think I might be adding an oiler in future..., But for now, it's done ;D

This has been an immensely satisfying project, and MANY thanks goes out to everyone who contributed, supported, encouraged and provided valuable input along the way. There's no final photo, as it would look just like the photo of the RT assembled earlier on.

I've had indecisive feelings about my next project out of three... My sister was visiting me this week from 1400km away and I C-o-C'd her the choices. From the three choices she had, she chose Elmer's "Comber", so tomorrow I'll be starting on that ;D

Regards, Arnold


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## bearcar1

Arnold, Chesterfields!??? (see post #140 item 6) Good Lord, those things will kill you man! :big:

I am constantly amazed at your well thought out and executed procedures. They seem so effortless, and to see such quality work is a pleasure to witness. Marvelous job my friend, it is always a interesting item to hear you speak of and explain your problems and workarounds as they present themselves. BRAVO! :bow:

I am anxiously awaiting to see your next endeavor with baited (albeit smelly ??? ???) breath. 

 :hDe: Does anyone have a Tic Tac?   Rof} Rof}


BC1
Jim


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## Diversion900

Just finnished reading the whole story.....

A truly magnificent piece you ended up with there Arnold, one that any machinist would be proud of.

Well done, and thanks for the wonderful tutorial as well.

Cheers, Neil


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## arnoldb

Thanks Jim ;D - those Cesterfields are a vice of mine :hDe: Got to kick that habit somehow, though I smoke a lot less while machining. Guess I'll just have to make more chips :big: No Tic Tacs needed; keeps open one's personal space in crowded areas; I use garlic for that :big:

Thank you Neil  - it wasn't intended so much as a tutorial as just a log of how I attempted it and to try to contribute back to the community; I learned a heck of a lot from members here and on other sites, even while building the RT, so it's only fair that I at least try and put something back. Nothing in what I described is fixed; a lot of the operations could be done in alternate ways. The favourite personal lesson I learned from this build: Even a relative newbie like myself can build some decent tooling if you really put your mind to it and is prepared to make an effort.

Kind regards, Arnold


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## Blogwitch

Arnold,


> Even a relative newbie like myself can build some decent tooling if you really put your mind to it and is prepared to make an effort.



Very good and true words. That is what home machining is all about.

You only get out what you are willing to put in.

You have really shown with this post, that even with limited resources and basic techniques, wonderful things can be made.


John


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## motoseeya

Arnald just found this thread and just wanted to say nice job. I wanted to try one myself but I,m scared to try it maybe I will after seeing what you have done. But you are far and away better than me but nothing ventured
 nothing gained.:hDe:


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## Shawn

Simply Brilliant work Arnold, my hats off to you. 

Shawn


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## jeanalvitre

Very well documented and very well explained. :bow:

thank you..


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## gus

Hi Arnold,
You letter stamp holder is just brilliant.Been racking my brains to figure out how to stamp the dial with numbers aligned.
The early lathe dials from India were awful looking with numbers stamped haywire.They make good lathes.
Plan to rebuilt a  3" R.T. sometime next year.
Will earmark this thread for future ref.


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## gus

gus said:


> Hi Arnold,
> You letter stamp holder is just brilliant.Been racking my brains to figure out how to stamp the dial with numbers aligned.
> The early lathe dials from India were awful looking with numbers stamped haywire.They make good lathes.
> Plan to rebuilt a  3" R.T. sometime next year.
> Will earmark this thread for future ref.



Hi Arnold,
Subsequent to above and to show support of your project,I am building one RT too.Was on a visit to my air receiver fabshop supplier,I had him fabricate the box frame and oxy-cut the square flange.Even had a spare set to back up just in case I goofed.See foto.
Did Trade School for three years way back in 1961. However did not pursue
the trade further as a machinist and hence my skill is very basic. Your thread
has given me so much know how. Will try best to measure up here in faraway Singapore.


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## gus

Hi Arnold,
Plan to use  same bearings.Please advise maker and his part number. Trust the weather is fine over at your end.


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## BaronJ

Hi Guys,

Bugger !  I've just discovered this great post on building an RT...
I ordered a new one yesterday.
This would have been a great build project for me.


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## excalibus

Arnold, I have to say you RT is very impressive, well documented and I would like to thank you very much for posting this here and by doing so allowing the rest of us to be able to learn from what you have done, and honestly it gives us all a quality of workmanship to aspire to 

I will be using yours and other peoples build logs on the rotary tables when I make my own some time, and I would like to thank all you guys who have made them and posted build logs, it really helps us amatuers learn and gives us guidance and a much better understanding of how to go about it 

Who would have thought that we could use a spiral tap to cut a worm wheel (for example) or that really machining a worm is no different to cutting a thread... Honestly making a hob - I could not get my head around until I saw your thread Arnold, and for Mike (I think was the one who used the spiral tap) bleedin' brilliance   and Dean, I have even looked up the link arnold posted here to your build and I am so glad Arnold shared that link too 

You guys really do rock!!!


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## bazmak

Just found this post and read it from front to back,so glad you ignited it
Brilliant


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