# Your Home Lathe Tooling



## rake60

The recent thread on HSS tool grinding has set me to thinking about my
own home shop lathe tooling.

I can grind a tool from HSS that I'd put up against any others.
Do I use them as my primary tools? No....

I own a full set of carbide insert tools.





First choice for the lathe? Not really...

My first choice is the brazed carbide bit tool at the top of this picture.




Yes there are a few HSS tools below them, but when it come to the 
bull work the brazed bits are what I depend on.

Now you can tell me about a tool that will take 1/8" depth of cut on a 
9 X 20 lathe, and I will be sure to file that information in an appropriate place.
_*(The east river is running high tonight, so it shouldn't have any lasting environmental impact.)*_

But seriously, What tooling do *YOU* actually use at home in your lathe?

Rick


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## Brass_Machine

I have a set of TCMM insert tools that I use






Image from LMS (where I bought them from)

However, I have a box of HSS blanks and a grinder for whenever I need to make a tool. Grinding tools was the first thing we learned in my Machine Shop class. We spent an entire night on them.

Eric


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## PolskiFran

My usual lathe tooling is a set of insert holders (like you have pictured). Most of my work is usually done in drill rod or O1. I like the ability to just change the insert if it goes south. I do have an assortment of tools at the ready for my QC tool post. Two sizes of HHS ground to a 90 deg. point for chamfering. Three widths of HSS parting (cutoff) tools. One 60 deg. HSS for threading. One short solid carbide boring tool. One sharp corner RH brazed carbide turning and two extra holders for the odd cutters. It is nice to be able to just grab the tool you want without having to constantly recenter, readjust, etc. 

BTW all of these tool holders did not come about overnight, I have been picking some up here and there over a period of years. I did start with a lantern tool post with tool holders and a small turret tool block. 

At the headstock end I have one 3-jaw chuck, two 4 jaw chucks (5" & 8"), 3AT collet set (.015" to .500"), two face plates and a few #3 morse taper fixtures.

At the tailstock live and dead centers. Having a few extra jacobs type chucks (1/4", 3/8" & 1/2" capy.) also comes in handy too.

Frank


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## BobWarfield

Well ya knew I'd have to get in on this one, LOL!






Most used work horses are the Micro100 CCMT holders. I run them with CCGT inserts (as discussed on the other thread) unless I have a really nasty interrupted cut, in which case I'll run them with regular CCMT's. 

I have some brazed carbide tools I bought, but they've never been used in the lathe. They go in my fly cutters. I'll have to give them a try on the lathe.

The most finicky tooling to get good results from has been boring bars and parting off tools.

I have found all the cheap import boring bars, including the CCMT bars that came in the turning sets, to be poor. I invested in solid carbide Circle boring bars with inserts for the lathe and they're fabulous: minimal chatter and clean cuts. I'm still looking for bars I like for my boring head.

On the parting off front, I have two tools that I like really well. First is an Aloris #71 QCTP carbide insert tool:






It's a workhorse, and will take anything I throw at it. If it squeals, it just means it wants to be fed harder. Took me a long time to get used to that on my small lathe--feeding harder often gets rid of chatter, but especially when parting off.

I also have a (surprise!) little HSS tool I like for parting small stuff. There's a seller on eBay ("samsws") that has these neat little parting off blades:






He makes 'em on his surface grinder and they work very well. 

The other things that makes all the difference in the world is I've got a variable speed DC motor on the lathe. 

Cheers,

BW


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## DICKEYBIRD

I used hand-ground HSS tooling for the 1st couple years and then bought a cheap Enco 3/8" insert tool set with TCMM (I think) inserts. I dropped the HSS almost completely and used the inserted tooling for everything with very good results. I'm lusting after some "real" insert tooling like Bob W has but the budget won't allow for it yet.

I finished a tangential HSS toolholder for the QCTP (John Moran/Gadgetbuilder design) last weekend and am just beginning to use it. The results so far are very promising and it was a fun project. Here's some pics:


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## jpaul

For lathe work I use HSS cutters almost exclusively. At present I don't have an adequate method of sharpening carbide tools. Aside from a dozen lathe cutters pre-mounted for Quick Change, I have a collection of small (.188" diameter) Form Cutters that I ground for a specific tasks. These cutters are not mounted since they are seldom used.

I came across hundreds of surplus 10-32 taps. No I didn't buy them all but I bought fifty or more at $4/lb. Over time I have used the shank of one of these taps to make a speciality cutter. To mount the tool I made several tool holders, featured by George H. Thomas


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## Bernd

Hey DICKEYBIRD,

The way that tool is held, looks simular to the advert in HSM and Machisnist Workshop. The call it the "Diamond Toolholder". Bay-Com Enterprises sells it. Their version is for the lantern style tool post holder. Is there a link to the Gagetbuilder?

jpaul,

Great idea using 10-32 tap bodies for cutters. Were does one get the surplus from"

Bernd


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## rake60

Here's the link to gadgetbuilder.com

A LOT of good information there!

Rick


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## Bernd

Thanks Rick. Looks realy interesting.

Bernd


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## Don Huseman

part up side down
I have a lathe that has a chuck that will not unscrew when you run the lathe counter clock wise and I turned the parting tool upside down and part that way. It jams every now and then and knocks to tool up . When you part in the normal manner when the tool jams it has a tendency to break the tool. The cutting oil seems to wick in the grove and oil the tool. I have a kdk holder and I just mount the parting tool upside down. 
Does any body else part this way or am I different.


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## chuck foster

i use a rear mounted tool post on my 9" south bend with the parting tool mounted upside down.
it will cut just about anything you through at it, square,hex and round. nothing seams to jam or chatter.
it is the best way that i have ever tried.


chuck


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## snowman

Two months ago, I used strictly carbide.

A month ago, I decided to learn to grind my own bits.

I used a carbide bit today because that's what was in the Aloris...

Now I use pretty much strictly HSS.

I've got a CRAPLOAD of random custom ground endmills that I will NEVER use. Yesterday I ground one down to become a boring bar. I also have a bunch of taps that I've been grinding up, and I'm always digging through machinists boxes at surplus stores and pawnshops.

I did however get screwed. Took quite a while and ground out a bit yesterday. Touched it to the workpiece...yep, beautifully ground piece of keystock.


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## Powder keg

snowman  said:
			
		

> I did however get screwed. Took quite a while and ground out a bit yesterday. Touched it to the workpiece...yep, beautifully ground piece of keystock.



At school, They had some neat surface grinders. I thought it was fun to grind up a nice looking bit out of mild steel and leave it on a bench somewhere. There was always someone to pick it up and try to cut with it. Someone donated 2" re-bar to the school. It didn't work too good to take the bumps off of that
	

	
	
		
		

		
		
	


	










Wes


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## wareagle

Powder keg  said:
			
		

> At school, They had some neat surface grinders. I thought it was fun to grind up a nice looking bit out of mild steel and leave it on a bench somewhere. There was always someone to pick it up and try to cut with it.



OT here.....  PK, That reminded me of when we would take our buddy's coil wires off their car/truck, and replace it with vacuum line, along with the boots. It was always on the "super mechanic's" ride, and it would piss 'em off when they realized what happened! Good times!!

Okay, back OT  For lathe tooling, I use the insert tooling about 75% of the time, the remainder is HSS. Nothing special in my box. In my experience (not that there's years of it), the HSS seems to give me a better finish than the insert tooling. It may be the inserts, operator error, or just dumb luck, but that is a trend I have noticed.

I did get one of those groove cutters from Enco that takes the inserts, and it is nice. One of my next tooling builds will be a scissor knurler.


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## DickDastardly40

Don Huseman  said:
			
		

> part up side down
> I have a lathe that has a chuck that will not unscrew when you run the lathe counter clock wise and I turned the parting tool upside down and part that way. It jams every now and then and knocks to tool up . When you part in the normal manner when the tool jams it has a tendency to break the tool. The cutting oil seems to wick in the grove and oil the tool. I have a kdk holder and I just mount the parting tool upside down.
> Does any body else part this way or am I different.



Don,

Some of the older lathes (sorry can't remember your particular set up) have an optional rear tool post, in which you mount tools upside down and continue to run the lathe forwards and bring the tool forwards to the work. This works very well for parting as the chips fall away and don't get stuck in the 'throat' of the cut. When I have mine fitted I use a parting tool or chamfer tool in it.

Al


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## S_J_H

> Now you can tell me about a tool that will take 1/8" depth of cut on a
> 9 X 20 lathe, and I will be sure to file that information in an appropriate place.



Well this is a pic of my old 9x20 taking at least a .125" cut in some 6061 using a Glanze ccmt insert tool under power feed. That was the norm for me on that lathe when roughing larger stock. .1" in leaded steel.





Steve


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## Bogstandard

Steve,

I use the same tips as you do on almost all my tipped tooling, and I have to agree with you fully. That wide angle face can really wack the stuff off. When they get worn on the faces, just use the tips in the tooling that uses the shallower angles.

John


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## Stan

I do most of my work with 6061 aluminum and O1 drill rod. Working with a flat belt Logan lathe I use HSS almost exclusively. I find carbide takes too much power which is not readily available with the flat belt drive. When I need a steel flywheel, a friend working at a steel supplier cuts it out of mild steel plate with a plasma cutter. I have to use carbide tools in the heat affected zone to rough it to OD and then go back to HSS for all the rest of the work. The problem when using carbide on this job is that it doesn't like interupted cuts and I don't have enough power to take off enough in the first cuts.

If I was in a production shop I would be using carbide, But I would be using a gear head lathe with lots of horsepower and lots of spindle speed. Any time the flat belt slips on my Logan, it totals a carbide cutter, but does no harm to a HSS cutter. I can take .001 cuts on O1 with HSS that I find impossible with carbide cutters.

BTW: I have an Aloris tool post with motley collection of tool holders, Aloris, import and shop made. I use mostly 3/8" cutters but may go as small as 3/16" threading bits to get right up to a corner.


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## Seanol

I use the grizzly version of the glanze tooling that Bob showed. After I went through all the inserts (they did not last long) I started grinding HSS and haven't looked back. While I love the finish and the ability to remove alot of metal, the HSS lasts longer in my still learning hands. I do have one problem with HSS. How to get the chips to break? On a-1 drill rod I get a very stringy chip.
I also use GTN parting inserts as well as standard t shaped parting blades. I use a little top rake and I have had very few problems. I do have a 13x40 Takang lathe so it is fairly stout.

Sean


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## BobWarfield

Steve, thank you for visually making a point I've had great difficulty conveying. With no intended disrespect to your 9x20 lathe, your photo immediately dispells some myths that one hears constantly around indexable lathe tooling:

1. I can't run my machine fast enough to take advantage of it.

2. My little hobby machine won't do carbide.

3. I don't have enough horsepower for carbide.

The other two chestnuts I hear often but do not have a problem with in my shop are:

4. You can't do interrupted cuts with carbide. Oddly so many people will use brazed carbide on a flycutter which spends it's life interrupted cutting.

5. You can't get a good surface finish with carbide.

Bog, your tip is excellent, and one I only recently figured out myself (sorry guys, I am slow!). The diamond CCMT/CCGT shape has 2 narrow points and 2 wide points. The tooling sets from Glanz and Micro100 have holders that use both. If you break or chip a point, there are 3 others that are usable in one or the other of your tools. It just means they last a lot longer than people would think.

Now lest ye think I am purely a carbide bigot, I am playing around with HSS grinding too. So far, I am not impressed if I have a carbide tool that does the same chore. However, there are many instances where there is no carbide available. Wes is doing a form tool for the columns on the team build. I love form tools and they're an HSS-only gig. No carbide inserts there! There are also specialty cutters for which good carbide isn't necessarily available. For example you can do a better job on a fly cutter or a boring head if you take a little care. Lastly, for tiny grooves and cutoff, I have an HSS parting blade I like that is smaller than my Aloris part off tool. No doubt I will someday have an indexable grooving tool, but this little guy is handy for small work and snap ring grooves.

Cheers!

BW


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## Powder keg

Bob, The tool I am making is tool steel not HSS. It is the same stuff they make drill rod out of. It comes fairly soft, then you heat treat it so you can cut with it. 

Later, Wes


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## Bogstandard

i mainly use my tipped tooling if i am removing large lumps, for fine precision work i invariably use hss ground up tooling. 

i do also relap the worn out carbide tips, using a water cooled lapping grinder, to the very sharp profiles of hss, but only use them on very fine surface work. if you try to remove too much material with them they just chip off almost instantly, but it will make a nice job on materials where hss struggles to keep a keen edge. i suppose you could use a diamomd lap to do the same thing.

as my motto is, use it until it has no further use.

john


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## rake60

Bogstandard  said:
			
		

> as my motto is, use it until it has no further use.
> 
> john



I like your motto John.
During WW2 we had a similar motto here. It was:
"Use it up - Wear it out - Make it Do or Do Without"
How well does THAT fit a home hobby machine shop?

Anyway...
We have carbide insert salespeople come into our shop on a regular basis.
Much of the new products lines are made up of insets with extremely aggressive
rake geometry's. Being I operate a CNC machine, I can click on the Load Meter 
screen and see exactly what kind of tool pressure is being generated.
It's amazing to see what's going on there. 
Higher SFM speeds, lower tools pressures and very little heat being transferred to
the work piece.

Those manufactures are not interested in selling a couple little inserts to some home
hobbyist, but I can guarantee that someone how IS will soon be making the small scale
tooling. 

The most recent new carbide that I am personally testing out at work is made by
SECO/Carbaloy. In looking through the documentation they provided with it, they list
the TCMT 21.51 inserts that I use in my home tools.
Their recommend depth of cut is .020" :

Rick


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## S_J_H

I no longer have the 9x20 and a rebuilt 1960's 9A South Bend is my main lathe now. Carbide is used 90% of the time on it. I use a 7rib serpentine belt flat side against the pulleys to replace the leather belt and it has a Leeson industrial 3/4hp DC motor and variable speed drive. Belt slip is almost impossible with this setup. It'll stall the motor first. Top speed is around 1400rpm. It will take a .125" DOC in 6061 without even breaking a sweat. CCGT inserts from Seco will easily take .001" finishing cuts and produce some beautiful finishes.
For boring I use only solid carbide bars. Under .001" doc is no problem when sneaking up on a bearing bore. I keep them razor sharp with a diamond file.
I only use HSS for form tools and parting/grooving. I personally love using carbide tooling.

Steve


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## chuck foster

i have a 9" south bend lathe and i use carbide tools about 90% of the time and i have no troubles with it.
i have a 1/3 hp ac motor on the lathe and i can take about .200" cuts in aluminum with the feed on the slowest setting.
the only time i use hss is if i'm grinding a form tool.

when i got the lathe i could not get a good smooth finish on my parts no matter what i did.
after a while and allot of bad words i discovered that the main bearings needed tightening. so i took about 3 or 4 tho. worth of shims out of the bearings and all has been good since.
for parting i use hss cutoff tool in a rear tool holder, with this set up i can part off square,hex and round very easily.

chuck


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## S_J_H

Chuck, you might get some interest out of how I line bored my 9A and made my own bronze bearing shells-
http://bbs.homeshopmachinist.net/showthread.php?t=26578

Yes I agree, .2" DOC are well within the limits of this machine. Not to take anything away from my old 9x20 and it even had a 1hp 3ph inverter motor and VFD, But my 9a SB is much more rigid lathe and the plain bearings produce a much nicer finish than the tapered rollers on the 9x20. In back gear which is a sorely missing feature of all the 9 and 10" import lathes, the SB is a massive step up in cutting power, At least with a modern belt on the flat pulleys. I run my bearing clearance at .0007". I loosen it to .0015" for 1400+ rpms and it will run well with well for extended periods getting only warm.
 Carbides and the old machines work very well.I find the good inserts to be much much better than brazed tip carbides.


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## BobWarfield

Chuck and Steve, your two posts make me wonder whether anyone has ever modified a 9x20 or other import to run with bronze bearings instead of cheap tapered rollers. Sounds like it would be an improvement and not all that hard to do with a line boring setup. I would think line boring would even have the virtue of (possibly) making the lathe more accurate in spindle to ways alignment if done carefully.

In terms of "warm", I wonder what the limits are for the bronze bearings? I would hate to give up my 2K rpm upper end!

Best,

BW


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## Powder keg

For 10 years I ran a Giddings & Lewis Horizontal Boring Mill that was made in 1905 and I could usually hold + - .0005" with it. It had this neat tapered Bronze bushing in the head that you could take up the slack in. The whole machine had bronze bushings through out. It is a fun machine to run. But very slow to todays standards. I rarely ran it over 200 rpm. 

Wes


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## S_J_H

> Chuck and Steve, your two posts make me wonder whether anyone has ever modified a 9x20 or other import to run with bronze bearings instead of cheap tapered rollers. Sounds like it would be an improvement and not all that hard to do with a line boring setup.


Bob, I am sure it could be done. A few issues might be a serious problem though. The spindle surfaces were never intended to be run in a plain bearing. I know my 9x20 spindle was not even hardened. I figure you are really pushing it at 2000rpm in a plain bearing with no pressure fed lubrication so you might loose some speed if it's your only lathe. 1400rpm on my 9a runs well though. My little cnc lathe will turn 4000+ and not even get warm , so I am setup for the smaller diameter work. The finish blows compared to the south bend though. 
I would run my old 9x20 to 4000rpm.,since it had a vfd 3ph setup. But it was far from smooth at that speed. I really enjoy the contrast of old vs new tech in my shop. I'm always on the lookout for another older lathe to restore.

Steve


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## BobWarfield

I assume the CNC runs in bearings? Tapered or angular contact?

Do you think that's the reason the finish isn't as good?

Interesting stuff here. Sorry to pester about these minutiae!  ;D

Best,

BW


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## snowman

I think it's great that you guys are so fond of the carbide...and I don't disagree that it's very capable of doing the things you have posted. I've got probably close to 3x the value of my machinery in insert tooling. I just don't use it anymore, unless I really need it. 

You take good pictures, they do not suprise me, I've done very similar things in the past....but I can do the same thing with a properly ground HSS bit of the correct size...and do it with less strain on the machine. Yes, you will occasionally have to touch up the edge, but you can buy a 1/2" HSS blank for what? $5 for quality stuff? It can be reformed into different cutters how many times in it's life? 5-20? Not to mention the amount of times it can be touched up. It may be lack of skill, but I rarely have a brazed carbide that "dulls"...it usually just chips, and doesn't leave much to grind back. I've watched inserts run for a loooong loooong time...and watched the spindle load, though they do use a little more power towards the end of their life, it is not something that I would likely ever notice on a manual machine.

Bob...on your list of 5, there's not a one I agree with, although I don't know how well carbide works on my 7x10 because I've never tried it  All are very possible, with the right tooling, and a little play with the feeds and speeds....and all are done in industry quite often.


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## rake60

I know I've said this before here but I'm going to state it again.

HSS _cuts_ metal.
It literally peels the material off the base stock, or separates the the
molecular bond material creating a stringer chip. It works best at
relatively low speeds and feeds.

Carbide _pushes _ the material off the base stock.
In order for that to happen it has to have two things. 
Pressure and Heat.
The tool pressure generates the heat that plasticizes the material 
to make it plyable enough to be pushed away.

The new carbide insert geometries concentrate that heat and pressure
to a finer point in the base material. That allows then to cut with less 
pressure.

It is an amazing study in it's self.

I've read many posts here and abroad from home machinists saying 
they can't get a good finish using carbide. 
That is caused by old school thinking.

HSS cuts very well at a 120 SFM 
For a 1" piece of 1018 cold roll *steel * that would be 460 RPM.

Carbide needs SPEED! It cuts best at 300 - 400SFM
At the low end of that range it would be 1150 RPM for 1" stock.

Calculating SFM (Surface Feet Per Minute) is an easy formula.
It is: SPM divided by Diameter of Stock Multiplied by 3.82

If you want the spindle speed for 2" stock to be cut with carbide.
(300/2) X 3.82 = 573RPM

Cutting with HSS
(120/2) X 3.82 = 229RPM

Now for Aluminium or Brass those speeds change dramatically!
You can run 1000SFM with no extra pressure on the tool or the machine.
That's kind of like the difference between chewing gum and chewing
stones. 

Rick


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## snowman

Correct..you'd also be correct in stating that a lot of the time, the surface finish that carbide leaves is from it actually burnishing the material as opposed to leaving a clean cut.


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## Mcgyver

Oh gawd, are we back on cutting tools :big:



			
				rake60  said:
			
		

> HSS cuts metal.
> It literally peels the material off the base stock, or separates the the
> molecular bond material creating a stringer chip. It works best at
> relatively low speeds and feeds.
> 
> Carbide pushes the material off the base stock.



Rick, I don't know that is correct - both cut via pressure creating a shear plane, the angle of the shear to the surface of the work being governed by the rake angle. With carbine requiring a larger included angle to withstand a given force, it presents a smaller rake angle and hence a more shallow shear plane. This affects us two ways, the longer shear plane means more force is required and secondly, the longer shear plane doesn't work well with a small doc - the shear plane is too long for its width and the tool burnishes. The speed limitation on either tool material is primarily a function of temperature (not heat!) at the tool tip, hss not be capable of maintaining hardness at the temps carbide can. I agree completely with your point about the effect of high temps/pressures, that there are different angles, temperatures etc, however the process of the metal being removed by shearing is the same - the main differences with carbide is it maintains its hardness at a high temp that hss and is more brittle than hss....pretty much everything else comes from that and understanding how a cutting tool applied to material at a certain angle causes a corresponding shear plane to form. 

just a general comment on this carbide/hss ongoing discussion to rationalize it for the new guy wondering whats going on..... An analogy to them might be to a professional photographer. He picks a lens for a job through balancing a bunch of different factors. That someone can say, well wait a sec, this lens can also take a pic, or, see I took a pic with a different lens doesn't really accomplish much and hardly negates the original choice. More constructive would be to try and lean F stops, depth of field and exposures and then try understand elements of composition and what he was trying to accomplish. Who knows, you may quickly surpass the pro and become new Ansel Adams....but you have to learn the basics as an important part of getting thereto be proficient


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## rake60

It is hard to comprehend Mcgyer, and dropping it on a beginner all at once would 
be confusing.

The company I work for is very dynamic when it come to new tooling that can 
increase our productivity. That means several seminars every year with the 
manufactures sales people and engineers to teach us how to use their products 
to their limits. Most of those seminars begin with the story of HSS tools and 
progress to their newest inserts. 

It does become very involved, but what is new and experimental in the large
job shop today will be available to the small scale hobby machines in the future.
The saying goes: "You Lead - Follow - Or Get Out Of The Way"
When it comes to tooling my company is definitely a Leader. 
I'll suck up whatever information I can from being a part of that!

Rick


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## snowman

And the beauty of working for a company that is the leader, is the packets of test inserts and the cabinets of obsolete tooling.


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## rake60

snowman  said:
			
		

> And the beauty of working for a company that is the leader, is the packets of test inserts and the cabinets of obsolete tooling.



Good Point! :big:

If anyone is shopping 60 degree triangle carbide tool holders, just visit
your local machine shop. 5 years ago that was cutting edge technology.
Today those shops would probably sell those tools priced per pound.

Rick


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## snowman

I've got enough VNMG holders and inserts (and seats and screws) to last me a few lifetimes. Even have inserts in wiper, diamond and ceramic.


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## rake60

This isn't home tooling by any means, but I thought some might be
interested in seeing it.

When I ran a big vertical boring mill we would get a few heavy jobs in
that were of Chilled Cast Iron. If you've never worked Chilled Cast 
imagine granite with spots of flint mixed into it.
It's tough stuff!

The parts we made were over 7 feet on the OD and called for a bore of
about 4 feet, 3 feet deep.

These are the carbide inserts we used to cut them.





The one on the left is new, the other had served it's purpose.
Surface speeds were very slow, usually around 150 SFM
Feeds were high, .032 to .044" per revolution.
The depth of cut was .375 to .500"
The holders set the inserts at a 10 degree angle but with "0" rake.
On a good day, one edge on that carbide would last 30 minutes of
continuous cutting. 
That old machine didn't have a load meter on it.
It did have an Amp meter that read the current consumption.
Sometimes we'd see 200 Amp reading while running those tools.
That couldn't have been good being the machine was wired to a 
100 Amp service. Many times it would blow the 100 Amp line 
fuses before you had a chance to react.

Rick


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## zeusrekning

I have never worked with parts that large. What kind of tolerance was the hole to be held to?
Tim


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## rake60

zeusrekning  said:
			
		

> I have never worked with parts that large. What kind of tolerance was the hole to be held to?
> Tim



The 4 foot bore was actually 48.005" +.002 -.000
Slop work compaired to model building!


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## zeusrekning

More details. How was it inspected. How do you work your way up to that dimension with out scraping.


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## rake60

Well this is getting way off topic, but I KNOW the originator of the thread
doesn't mind! 

zeusrekning you reach that size by brute force until you get to within
.100" then it becomes a finesse thing. That same machine that you just
beat the crap out of is expected to cut a perfectly straight finish cut.
It WON'T! Finishing is a series of light finish cuts. It might cut on size
at the top, -.002 in the middle and back to on size at the bottom.
You would calculate that cutting arc in .0005" increments.
as the head was feeding down you would manually "bump" the tool into the
cut .0005" at a time to the center of the bore. From there you would bump 
it away from the cut .0005" at a time until you ended up at the beginning 
reading. The stock we worked with cost a bit more than what I work with 
at home. You DIDN'T want to make an error!

One time we were making a large 8 foot OD brass bushing.
6 people had already told me that the casting cost $47,000
I said if one more person reminded me of that I'd part the damn thing in half.
A 5 minute break to the locker room resulted in SOMEONE taking a yellow
paint marker to it. The bold bright writing read:
*"RICK I COST $47,000 DON'T F&*% ME UP!"*
I never did find out who had added those little words of encouragement. LOL

We have a tubular inside mic set manufactured by Mitutoyo.
It's measuring rage is from 40" to 160"
It looks very much like this.





It's checked for calibration using only the 40" assembly against an inspected 
40" Mitutoyo Outside Mic. 
For any size with a tolerance of .005 or less it's readings are verified but checking the
mic with a 60", 84" or 120" vernier caliper. Yes we DO have Mitutoyo Vernier Caliper
that will measure up to 10 feet. It requires 3 people to use it at that distance.
One person holding the "dumb end" one in the middle to give the beam just enough
upward pressure to remove and sag, and the man at the "smart end" taking the 
measurement. Everyone there has to know what they are dong to get an accurate 
measurement. We're either good at it, or we've been very lucky. We've never had
a large part returned for an errant size.

For anything over 120" we use Pi Tape's 
I had a post regarding them here. Pi Tape
We have Pi Tape's that will read up to 15 feet or 180 inches.

I worked on that scale for almost 20 years and then decided to make model engines
at home. I've been a machinst for 30 years, but this scale is a whole different world!

Rick


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## BobWarfield

Good stuff!

I've been reading about this "tool bumping" for some time and actually tried it on my home lathe. I wanted to see if I could improve the accuracy on a long shaft that was getting a little taper if left to it's own ways. 

Worked out great!

Best,

BW


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## rake60

BobWarfield  said:
			
		

> Good stuff!
> 
> I've been reading about this "tool bumping" for some time and actually tried it on my home lathe. I wanted to see if I could improve the accuracy on a long shaft that was getting a little taper if left to it's own ways.
> 
> Worked out great!
> 
> Best,
> 
> BW



I bumped tools for 20 years.
Now I really appreciate a CNC machine.
Their not perfect! They will still taper.
Beauty is if you have a -.003 taper over a 20" length you just adjust the program.
To make it simple if your cutting 1.000 diameter program X diameter for 1.000 at Z 0 
and X diameter at 1.003 at Z 20.00 You end up with a perfectly straight fit.
That beats the hell out of trying to manually bump a lead screw .0005 at a time. 

At home it's still done the old way.
It feels pretty good when you mic that fit and it's perfect for it's entire length.
It's not the machine that makes that happen, it's the touch of a machinist. 

Rick


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## Mcgyver

I enjoyed that account - keep em coming! For me the fun is mostly in the solving the puzzle. It's not often i get first hand exposure to 10' dia puzzles so learning how they're solved is always of interest. with those very large measure instruments, how attention was paid to thermal expansion......at 10', 5 degrees of warming up from handling would change the measurement by .003!


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## rake60

I'm pretty sure I had posted this picture somewhere here before,
but this is the actual machine that I ran for 20 years at the place I
still work for.




The man at the controls is by buddy Duke. I worked opposite him
for that entire time.
That Vertical Boring Mill was manufactured by Osaka Machinery LTD of
Japan in 1973. It's 35 years old and still ready to work hard everyday.
We'd referr to it as a Horse of a Machine.
It has a maximum swing of 177" and 36" or ram travel.
I personally have turned parts on it that weighed just over 32,000 pounds.
I miss running it sometimes, but I DON'T miss the climbing over, under
and inside of parts to do the set up work. 
I'm just plain too old for that stuff! 

Rick


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## lathe nut

Rake60, that's a real man's toy, what kind of parts do you all make, what kind of business at the parts that you make used in, thanks for the pic's and information, LatheNut


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## rake60

The most comman parts, made or repaired on that machine are either
crane/dragline parts or aggregate industry (rock crusher) parts.
Of course there are many other jobs done on it but those two are the
majors. 

I've mentioned cutting buttress threads that were 1.032 deep with a 
2.000" lead. Those are for rock crashers. We cut both the internal
and external threads for them on that machine. 
That machine was not originally designed to thread.
It was an in house venture to fit it with a direct drive gear box to
make that possible. Once the threading gears are engaged they are
not disengaged until the thread is finished. To relieve tool pressures 
the saddle is gingerly bumped up and down using the traverse buttons.
Some of the parts we put on that machine were too heavy for the 
10 Ton overhead crane. There is an axillary 5 Ton crane on the same
rails. A spreader bar was designed that would place 66% of the lifting
force on the 10 Ton and 33% on the 5 Ton.
We exceeded that at times.
That is acceptable.
You can legally exceed the rated capacity of an overhead crane by 50%
As long as the crane is inspected immediately before and after the lift.

Rick


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## alan2525

I bought some parting tools from the guy on Ebay -SAMSWS but his postage costs to the UK were rather high!


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## Paolo

While I was deciding which burner to be used..I made some slitting harbor...I made also one for the Hilmar blade...!! Tommorrow I have to use it for the doing the strip for the second burner on my project!! Noting too difficult..but a present to Hilmar...Thanks again my friend...I'll maintain my promist!!!


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