# Rotary tables - how often are they actually used?



## Swede (Sep 14, 2011)

I have a question for experienced hobbyists... how often do you actually use your R/T? Many years ago, when I was into acquiring tools and tooling, I picked up a truly sweet Yuasa 5" R/T. I cleaned and oiled it, and put it on the top shelf.

Decade(s) later, it has never been used.

I have used my dividing head extensively for gears and splines. I've used a 5C spacer for similar tasks. For bolt-circles, I use a simple computer program that outputs X, Y coordinates for any bolt circle imaginable. And for those occasions where I need to cut an arc of any size, I turn to the lathe.

If one's mill has no DRO, then I could see the R/T as being very important for bolt circles. And without a dividing head, you'd need one for gears, although I shudder at the work involved in progressively adding up degrees, minutes, and seconds, to cut an oddball gear tooth number.

Does anyone use their R/T for a specific operation that cannot be done on another piece of tooling?


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## Sparticusrye (Sep 14, 2011)

I haven't used one often, but I did use one to help a friend to customize a flywheel for an air engine. He had a complex design that he wanted machined into the hub. So I had a large Rotary table with an indexing head on it so that I could achieve the compound angles that he required. That was a long time ago and there are much easier ways of achieving the same result now. But we didn't have a CNC machine in the shop at that time.


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## JorgensenSteam (Sep 14, 2011)

You can use them to make the Stephenson's links for steam engines.

Pat J


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## mklotz (Sep 14, 2011)

Swede  said:
			
		

> And without a dividing head, you'd need one for gears, although I shudder at the work involved in progressively adding up degrees, minutes, and seconds, to cut an oddball gear tooth number.



Do that and the accumulated round-off error will kill you. This is a trivial operation on the computer - see my ROTARY program.


```
Number of divisions = 13 

DIVISION   degdec   deg   min   sec
    0   0.0000    0    0    0
    1   27.6923   27   41   32
    2   55.3846   55   23    5
    3   83.0769   83    4   37
    4  110.7692   110   46    9
    5  138.4615   138   27   42
    6  166.1538   166    9   14
    7  193.8462   193   50   46
    8  221.5385   221   32   18
    9  249.2308   249   13   51
   10  276.9231   276   55   23
   11  304.6154   304   36   55
   12  332.3077   332   18   28
   13  360.0000    0    0    0
```


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## kcmillin (Sep 14, 2011)

Any time I need to mill a radius on something I get out the rotary table.

Her are some pics of things I have done on the R/T that cant be done on an indexer without some way of turning the table while milling.

A hall sensor strap for the TI4 Distrubitor






Timing Cover 










Here I am milling out the water jacket on the TI4 with a key cutter.





Flywheels 





Here are some Radius's on MY Double Poppin Standard









I am sure there is more than one way to do this though, this is just what I do.

Kel


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## kvom (Sep 14, 2011)

I used one the first time at school to mill the spokes on the flywheel of my first engine, and then I bought my own to machine the crankcase and a few other operations for the Liney Halo 5-cylinder engine. However, since I acquired my CNC mill my rotab has been sitting idle.


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## mu38&Bg# (Sep 14, 2011)

KVOM has the answer. I've made plenty of parts that would, if not for CNC milling, require a rotary table. I do not own a rotary table other than the one I'm putting together to add a 4th axis to the CNC.

The guys that can do wonders on a manual machine use them a lot.


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## Ken I (Sep 14, 2011)

I use mine a lot - more than I though I would - but then I don't have a dividing head or NC.

My 6" vertex does have an optional set of division plates and detent pin handwheel a'la dividing head.

Ken


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## pete (Sep 14, 2011)

Ken,
I've got the same R/T and dividing plates. For what the add on dividing plates cost their well worth it. Since I bought them I wouldn't buy another rotary table that didn't have these as an option. To be honest, A rotary table without the dividing accessory is only half a R/T to me.

Pete


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## Maryak (Sep 14, 2011)

Because I know zip about CNC, my rotary table is an indispensable accessory for use with my mill and I use it for any milling operation requiring going round corners as well as gear cutting. Probably the only thing it can't do, that a dividing head can, is cut helical gears.

I would not part with mine 8)

Best Regards
Bob


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## Troutsqueezer (Sep 14, 2011)

Swede  said:
			
		

> Does anyone use their R/T for a specific operation that cannot be done on another piece of tooling?



I use mine quite a bit. As you know, a lathe can make many of the same cuts that can be made on a mill but I wouldn't give up my mill for anything. Same for the RT.


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## Blogwitch (Sep 14, 2011)

When I am in my shop, I use mine a lot, anywhere where radius milling and hole drilling around a PCD is required, even though the second job could easily be done using my DRO.

I do have the advantage of running mine from a Division Master which is a form of NC, and I will soon be modding my dividing head the same way.

In fact, I have both my vice and RT mounted onto the table at the same time, which I think makes it easier for me to use it, I don't have to fiddle about swapping it out with the vice, which I think is why a lot of people with RT's tend to do things by using other means first.


John


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## Ken I (Sep 15, 2011)

I've fitted my RT and various vices with tennons - so that I can bolt them to the table and (generally) not bother to clock up.

Ken


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## mzetati (Sep 15, 2011)

John,

I do not have room/travel enough on my mill table to keep both the RT and vice ever ready on the mill.
Found a way to clamp the RT without removing the vice.
 ;D

Marcello


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## Swede (Sep 15, 2011)

There's definitely some good examples of work that use the R/T here. I have used one in the past, but I've always thought the setup was a pain, and in general, I've always figured out a way to work around it.

For arcs, 80% of the time, I'll use the lathe and then mill or cut out the arc section I need. I've also used boring heads for both inside and outside arc segments. And I can absolutely see their utility for flywheels and some other oddly shaped widgets.

Thanks, I was just curious as to how much other guys used theirs. And I'll agree, if given the choice, absolutely pick up an R/T that can double as a dividing head with the correct plates... I love my dividing head and use it often.


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## petertha (Sep 15, 2011)

Im glad this post got initiated. A few years back I bought an 8" Taiwanese RT. I didnt buy the dividing plates at the time which probably was a mistake. I'm pretty sure its the same as this one offered by KBC & was thinking of picking up the accessories.

Re RT dividing plates, do you unscrew the graduated dial, bolt on the plates + detant pointer thingy & thats how it indexes? Looks like they size them by the nominal table diameter... I hope they fit.

Also, do you guys use the tailstock accessory much?


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## petertha (Sep 15, 2011)

Another question. From some of the RT milling examples, it looks like having the ability to quickly locate a base plate fixture or the milling part itself on the RT center would be useful. I envisioned an MT3 plug that drops in the RT, below the surface of the table. It would have a precise hole sized for a removable dowel pin. Nothing like this seems to exist in tooling catalogs from what I can tell. Do you guys have a procedure for this type of operation, or am I making a big deal out of nothing? Ivethough of lopping off commercial MT arbours but I'm leary that they are hardened. I wish the RT tapered center hole was an ER taper or something, those collets would be perfect!

On trick I use for centering my 3-jaw chuck on the RT for is: drop an MT3 arbor into the RT. It has a straight section that extends a couple inches above the RT table. Lightly clamp the chuck jaws to the arbor, now its centered. Then secure the chuck to the RT in that position & remove the arbor. (I still have to make myself a better mounting plate vs my jerrry-rig, but this works good from the quick positioning perspective).


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## pete (Sep 15, 2011)

Petertha,
You can buy what are called by some companys, MT blank arbours. Their soft, and for at least the MT 2 come with a 1" plained turned section. You can modify them easily to what's needed. Not too expensive either. About $10 each for the MT 2.

Pete


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## mhirst121 (Sep 15, 2011)

An old or broken mt drill can be used for the mt. I cut off the end of an old drill and mounted in the lathe headstock centre and faced off and centre drilled, a point was then turned from another piece of bar. the point is put in my er chuck and the centre in the rt, thehead is then lowered to lace the point in the centre drill hole and voila the table is centred.
martinh


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## petertha (Sep 15, 2011)

pete  said:
			
		

> You can buy what are called by some companys, MT blank arbours. Their soft...


Thats good to know, I'll commence locating them. What would be a good way of holding a tapered MT arbor part like that in the lathe in order to do operations like facing, machining an end profile, center drilling etc?


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## chucketn (Sep 15, 2011)

If your lathe headstock has an M3 taper, you can get an M3 to M2 adaptor or sleeve to hold the M2 blank arbor.

Chuck in E. TN


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## pete (Sep 15, 2011)

Chuck beat me to it and said everything I would have but I'll make one addition. For work of this type it's not something you rush into. If it's going to be a usable and accurate tool accessory then your machining accuracy needs to be as perfect as you can make it. 

Pete


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## petertha (Sep 15, 2011)

My lathe headstock taper is MT5. Plus I seem to recall the OD of the RT hole top at the turntable require lopping off a good portion of a typical MT3 arbor in order that the plug would sit just below flush. Maybe if they made an adapter sleeve with zero taper OD & MT3 taper ID, I could chuck it? 
I'ts starting to come back to me now why this 'simple' little RT alignment jig remains unfinished ;D


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## Troutsqueezer (Sep 15, 2011)

I bought a 3 jaw from H.F. for $24 that fits exactly inside my 6" RT which has an MT1 taper. Makes aligning easy and holding small parts as well.


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## Ken I (Sep 16, 2011)

A couple of self explanatory photos - I often take my 3 or 4 jaw lathe chuck over to the RT (often with turned part in it.)

I like to have the float this allows me to clock it.






















Ken


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## petertha (Sep 16, 2011)

Ken I  said:
			
		

> I like to have the float this allows me to clock it.


So I assume you just remove the 3 pins (D1-3?) from the back of the chuck so it lays flush with your RT mounting plate?


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## gbritnell (Sep 16, 2011)

I use my quite a bit. Once you get method down for aligning the axis of the table and spindle the tool becomes almost indispensable.
Here's the link to my V-twin build. On page 3 you can see one of the setups.
http://www.homemodelenginemachinist.com/index.php?topic=6847.30
gbritnell


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## petertha (Sep 16, 2011)

gbritnell  said:
			
		

> I use my quite a bit. Once you get method down for aligning the axis of the table and spindle the tool becomes almost indispensable. Here's the link to my V-twin build....
> gbritnell



Wow, thanks for providing that link. Ive only been a newbie lurker for a short while so that's another great build thread to follow. I noticed on post #154 you have a jig plate set up on the RT. From what I can tell, you lower an insert into the hole of the jig to center it on the RT. But now with that done, how do you also get an edge of the jig plate aligned to a datum, say say the mill x-axis (using the dial indicator) without disturbing the hole centering? Thats kind of why I was thinking of making MT tapered plugs for the RT with dowel pins - something to rotate the jig about. Hopefully this rambling question makes sense.

http://www.homemodelenginemachinist.com/index.php?topic=6847.150


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## Ken I (Sep 17, 2011)

petertha  said:
			
		

> So I assume you just remove the 3 pins (D1-3?) from the back of the chuck so it lays flush with your RT mounting plate?



The chuck bolts on to the adaptor plate (via the three bolts and loction ring) which then bolts to the RT faceplate. 

I have a further arbor and location ring which aligns it on centre - but quite often I will leave them out and allow it to float (only by the clearance of the 4 mounting bolt holes) and clock it into place - obviously tapping it gently with a soft hammer etc. etc.

It depends on how accurate you need to be WRT accuracy of the centreline. Example milling a hex or pitch drilling clearance holes not too critical - but for the radial spacing of a V or radial block I would want the centre to be spot on.

Ken


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## coffeebean16 (Sep 23, 2011)

okay im new and i read the thread. 
i have a question: is a dividing head the same as a rotary table with dividing plates?
which one of the two is required to cut helical gears?
they seem similar, maybe comparable, maybe even the same.
thanx for your answers
dave


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## Ken I (Sep 23, 2011)

Coffeebear,
A rotary table is typically fixed in that the axis can only be horizontal or vertical (although there is nothing stopping you from mounting it on a a sine plate or similar) - a dividing head is inclinable through 90°.
A dividing head also has the ability to drive the index plate via a geartrain so that you can generate rotation in synch with your leadscrew for the production of helical gears.

Rotabs are typically 90 revs = 360° whereas dividing heads are 40 revs = 360°.

So you can't do helical gears on a rotary table - for that you need a dividing head.

A rotary table takes up a lot less vertical space then a dividing head pointed up when you want to generate rads etc.

Ken


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## coffeebean16 (Sep 24, 2011)

thank you


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## MarioM (Nov 30, 2012)

Hi Kcmillin,

 In one of your pictures I realized you made an extension from a plate and put it on top of your rotary table......this is the idea I was looking for.  Could you please give a bit of information regarding the sizes and material you used.  My rotary table looks very similar to yours....4" bought from littlemachineshop.  Thank you,

Mario





kcmillin said:


> Any time I need to mill a radius on something I get out the rotary table.
> 
> Her are some pics of things I have done on the R/T that cant be done on an indexer without some way of turning the table while milling.
> 
> ...


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## gbritnell (Nov 30, 2012)

In the home shop a lathe and a mill are probably used most of the time with standard tooling but when it comes time to make irregular shapes a rotary table can be very handy. If I look at all the tools I have accumulated over the years, bought or made, a lot of them don't get used very often but when they're needed nothing else will work. 
I have a horizontal/vertical rotary table with dividing plates that I made myself. When I first thought about buying it I tried to rationalize use versus cost. 
It all comes down to how you would make a part without one. If you scratch build at all then you would probably have a need for one but if you just work from castings you could get by without one. 
Look at your long term modeling goals to determine how much use it will get. 
gbritnell


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## gbritnell (Nov 30, 2012)

To do this job without a rotary table would be almost impossible.
http://www.modelenginemaker.com/index.php/topic,570.15.html


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## Mastermaker (Dec 4, 2012)

One thing that a rotary table can do is increase the surface you can face beyond the capacity of your Y-axis.

A friend of mine made a router table a while back and the router mount plates available were either to expensive(WAY) or not good enough.

Some mdf was given tapped holes coinciding with the countersunk mount holes that were drilled  in  the alu plate first, bolted the mdf to the rotary and then screwed the alu plate on top and some machining time later this was the result.


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## SmithDoor (Dec 4, 2012)

My self over 40 year I have gone years and never use a index head or rotary table. Then I will use on almost ever day for years. It is the type of work you are doing. I use both and like over the other for different jobs. 
I know this does help mush but it is the best any can give you.

FYI there two type of indexing heads one is for just indexing making spur gear the other is for making helical gears. I use a BS-0 (Semi-Universe index)with 25 lb the other is a BS-2 (Universe index)over 120 lb. Some day I plan to make my BS-0 to a Universe index. I have owned both .

Dave



Ken I said:


> Coffeebear,
> A rotary table is typically fixed in that the axis can only be horizontal or vertical (although there is nothing stopping you from mounting it on a a sine plate or similar) - a dividing head is inclinable through 90°.
> A dividing head also has the ability to drive the index plate via a geartrain so that you can generate rotation in synch with your leadscrew for the production of helical gears.
> 
> ...


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## GWRdriver (Dec 4, 2012)

Maryak said:


> Because I know zip about CNC, my rotary table is an indispensable accessory for use with my mill and I use it for any milling operation requiring going round corners . . . I would not part with mine


It depends upon many factors, including your particular projects and chosen machining practices, but generally I agree with Maryak, I use mine for anything that requires a machined radius.  I build locomotives, and I might only use mine 2-3 times a year, but when I need it I _NEED_ it!

My R/T is a rescued (and rebuilt) US-made 9" Troyke, made in 1953, which is built like the proverbial battleship.  I found it as a grime-covered piece of junk being sold with some other obsolete tooling from a tool & die shop in Ohio.  It turned out to be virtually unused underneath all that grunge.  The great thing about it was it was designed and made to be completely adjustable and rebuildable and the "manual" was still available.

BTW, this R/T weights in a 38lbs and is my heaviest accessory, and the heaviest I would try to lift to near chest level (the mill table) without assistance.


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## gus (Dec 4, 2012)

Was building an "American Pop Corn Engine" which required two brass ball flyweights and the governor body which were near impossible to hand manipulate slides and turn to satisfaction.A Rotary Table would be best solution.Buying a Rotary Table was out of question which means  shelving job for two weeks plus the expensive end cost of RT cost + the DHL. Freight to Singapore would be bomb. DIY my own RT.Was lucky to locate Japanese worm and wheel stockist.The ones I later bought in China at 1/10 the price looks poor quality. 
Foto of RT and engine attached. There are many other applications for RT. Small end of con-rod is one.
Tee slots were cut later when Tee Slot End Mill came in from Arceurotrade. No drawings were made. RT made on play by ear basis.


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## nemoc (Dec 4, 2012)

I use mine a lot.  Almost every project.  I don't really need it, but it lets me add some style to my engines.  Here are some pics.


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## modelman1838 (Dec 5, 2012)

Many years ago I made a small non geared rotary table to a George Thomas design, and of all the tools I have made this is the most used. Any job with an external radius and out it comes.
 Hugh


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## gus (Dec 6, 2012)

Hi Nemoc,
You make very good looking flywheels. The next slide valve engine I build will have solid one piece wheel with multi spokes.
You have lit the path to good looking flywheels.


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## nemoc (Dec 6, 2012)

Thanks Gus.

Craig


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## goldstar31 (Dec 7, 2012)

modelman1838 said:


> Many years ago I made a small non geared rotary table to a George Thomas design, and of all the tools I have made this is the most used. Any job with an external radius and out it comes.
> Hugh


 
I have made up the same but the geared version( Hemingwaykits) - and enjoyed the tool.
again, I have something similar on the Clarkson tool and cutter grinder radius attachment and on the home made Quorn tool and cutter grinder.


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## gus (Dec 7, 2012)

Hi Craig,

Forgotten how to post new threads.Please give some pointers.

Now working a Quick Change Tool Post. Upgrading from the existing DIY Tool Post. 

ABout to go fishing.Good weather window.

Thanks.


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## Cogsy (Dec 7, 2012)

gus said:


> Hi Craig,
> 
> Forgotten how to post new threads.Please give some pointers.
> 
> ...


 
PM sent Gus.


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## thayer (Dec 8, 2012)

I fired up my RT tonight to drill the bolt circle for the head and cylinder on my latest project. You can see the outcome in post #25 of my build thread, Elmer's #33 - a novice makes chips.
http://www.homemodelenginemachinist...vice-makes-chips-19478/index3.html#post202407

Thayer


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## gus (Dec 8, 2012)

Cogsy said:


> PM sent Gus.



Thanks Cogsy.Had it written down. Just wondering how I posted the Firefly thread.


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## incawannabe (Dec 15, 2012)

if anyone is confused about the vernier scale on their rt there is a detailed description at grizzly.com/manuals/h7527-m.pdf


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## GWRdriver (Dec 15, 2012)

I thought I'd throw my 2p worth in with an example of adapting and extending the tools at hand (in this case my rotary table) to do more than it was intended to do on a one-off job.

The task:  The slots in the main axleboxes (bearing boxes) of most miniature locomotives call for a slight radius in the sides or "cheeks" of the boxe slots so that when sprung axles rise and fall unequally the boxes won't bind against the frame or the horn slots.  Each axlebox has four radiused cheeks.  For my project I needed a radius of 10.5" but having only a 9.25" rotary table (giving a max 4.625" radius work surface) an extension of some kind was required to give the 10.5" radius plus several inches to provide a working surface.

The old-school model engineering technique (and I am old school) has been to attach a plate to the rotary table, thus artificially extending its capacity, and clamp things to that, keeping in mind the rigidity will be a concern.    I happen to have on hand a clean piece of scrap 3/4" steel plate (1/2" would do) which I used for the extension plate.    This was drilled and bolted up and then a seat was precisely milled (notched) to receive a steel block to act as a "jaw".   This jaw was located so that when the boxes were clamped in, and a pre-determined dial reading was arrived at, the crown of the radius would be located exactly as required.  I simply rotated each box four times, cranked the cutter back and forth through an arc until I reached said dial reading, and wallah!

All of this was indicated in to assure that the radii were centered in their axleboxes and this setup will be used again in the future when it comes time to mill the expansion links and die blocks for the Walscheart valve gear.


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## AssassinXCV (Dec 20, 2012)

Might have missed it if it was already posted, but another use for a rotary table is to make the crank cases for any number of cylinder RADIAL ENGINES.

Here's how I made the prototype crank case for my 8 cyl radial engine I'm taking forever to make:


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## gus (Dec 20, 2012)

Planned to use the RT to turn the knobs for QCTP cam lock lever but would mean I have to buy a 1" brass bar.
Passed by a "Nuts & Bolts" shop and bought the Red Plastic Knobs. The Knobs seem to add color to a dull M.S.
 QCTP.The red knobs cost peanuts.


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