# Chuck to Rotary Table Options



## negativentropy (Mar 13, 2013)

I want to mount my 4 jaw (5") chuck to my 6" rotary table.  What options do you recommend:

1.  Make a back plate.
2.  Drill 4 through holes on the chuck to allow connecting to t-nuts directly

The chuck is about 3" thick.  Will I run into problems drilling this?  Is there any mechanical bits that I would be drilling through?  Its a 4-jaw independent chuck so Im presuming all the mechanical parts are directly beneath the jaws and its safe to drill between the jaws on the outer edge of the circumference?


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## Richard King (Mar 13, 2013)

I would not drill holes into the chuck, I would go with mounting a back plate on the chuck and either use the tee slots / tee nuts or toe clamp it down.  That way you can indicate iand tap it in so the chuck so it runs true to the rotary table  I would bet there is drilled and tapped holes in the back now?  Take a couple of pictures and attach them so we can see.    Rich


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## negativentropy (Mar 13, 2013)

So there is 4 threaded holes for the lathe adapter plate.  I would use those for bolting to the rotary plate.  I cant see how clamping would be possible, there is just enough space for a hex cap screw, but nothing more - hence the drilling through consideration.


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## 8ntsane (Mar 13, 2013)

You do have options.
The chucks can be threaded on the back side, or have through holes from the front.
If your R/T has 4 slots, mounting should be as easy as making T nuts, and mount it up.
Really it mostly depends on the chuck at hand. Some have the bolt circle at the outer edge,
other don't. Some with through holes, other with threaded holes from the back. You might want to 
choose your chuck carefully because of this. They are not all the same. The pic shows the chuck in the front as is, and the chuck in the back ground has been drilled through. Notice the bolt circle on both.


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## pineyfolks (Mar 13, 2013)

Make a spool out of 2 plates with a center section tall enough to get your bolts in.  Bolt the plates and center section together then bolt it to your rotary table and bolt your chuck on. You can make out of 1 piece if you have the stock. Just offset the bolt holes so they don't hit.


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## Cheeseking (Mar 13, 2013)

This is what I did just last weekend....
I had one of those cheapie 3" 5C chucks I rarely use so I decided to mount it to a plate which can in turn be mounted to the rotab.  My rotab has a 1.000 dia straight bore center hole so I machined a matching hole in the plate concentric with the recess for the chuck.  I have a .9995 pin gauge and use it to align while tightening the bolts to t slots.


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## bmw rider (Mar 13, 2013)

From the looks of it you have exactly the same rotary table as I do and the same chuck I bought to mount to mine. I just made an adapter plate out of 3/4" aluminum. I drilled it to the bolt pattern of the chuck and countersunk the allen bolts. Then I drilled just outside the diameter of the chuck to mount to the T slots of the table. I had to mill down the T nuts a bit to clear the lock clamps on the table. I picked up an MT2 arbor with a plain 1" end to use to center the plate on the table. I"ll try to get some photos of it shortly and post them to help you out.


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## negativentropy (Mar 14, 2013)

bmw rider said:


> From the looks of it you have exactly the same rotary table as I do and the same chuck I bought to mount to mine. I just made an adapter plate out of 3/4" aluminum. I drilled it to the bolt pattern of the chuck and countersunk the allen bolts. Then I drilled just outside the diameter of the chuck to mount to the T slots of the table. I had to mill down the T nuts a bit to clear the lock clamps on the table. I picked up an MT2 arbor with a plain 1" end to use to center the plate on the table. I"ll try to get some photos of it shortly and post them to help you out.



This is what I ended up doing.  I like the MT2 idea.  I have a dead center I could use to do the same thing.  It would save a bit of fiddling around - although I figure with the independent chuck Ill have to zero it in anyway, so the chuck doesnt have to be dead on the RT to begin with.  

What I will do tomorrow is add the 3-hole circle for my 3-jaw chuck.   In which case having an easy way to quickly center the plate on the RT would be handy.


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## RandyM (Mar 14, 2013)

I am confused as to how you'd mount the chuck directly to the indexer, I mean I how'd you tighten the studs?:think1:

Here is what I did, an adapter plate.


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## GK1918 (Mar 14, 2013)

Thats real nice Im working on a different approach.  Material 3/4 X 12 X 16 free and been surfaced,
teacher freind in tec. school.  another freebe 10" 4 jaw (camlock) that i cant use.  Chuck is new.
The chuck bore is about 2or+ inches.  So far I turned  a short piece of stock just about dead on and
lapped it in the chuck with valve gr.compound.  Nice fit no slop.  Then I milled to flats on that (stub)
on the shaper.  Put the stub in the mill vise indicated that then put the chuck on the stub and didicated
the chuck.  Chuck spins with precision.  I have to now bore the plate for the chuck stub, put on hold
My boring bars dont fit my boring head gotta buy some.  I have already indicated the chuck sitting
flat on the plate and thats good.  When assembled the chuck will actually ride on the plate so it will
have a little drag.  last, four eccentric threaded pins into the plate when tightened they will lock the
chuck.  My biggest problem is These parts are heavy I mean heavy.  Oh the chuck is not in the center
lenght wise on the plate I left room for someday, I figure some type of crank for 40:1, could even
be a fan belt-cog belt maybe.  For now old school protractor.   This is shelved for now I got a first
time for me job comming needs a lot of thought.  I shall attempt to fly cut a 6cyl exhaust manifold
never done that, we always sent them out but nobody does that around here anymore.  Shame.
got to come up with some serious clamps.   gotta get a camara batt  todays list should have pics today.


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## eac67gt (Mar 14, 2013)

Randy we have a 4 jaw chuck that I need to mount to the rotary table and I like your idea. I will have to look at ours closer and consider very closely going your way.

Ed


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## RandyM (Mar 14, 2013)

eac67gt said:


> Randy we have a 4 jaw chuck that I need to mount to the rotary table and I like your idea. I will have to look at ours closer and consider very closely going your way.
> 
> Ed



Thanks Ed, I am mounting an 8 inch chuck to an 8 inch indexer. As you can see things got a little tight, but work. I too need to get a 4 jaw chuck and do the same. If I recall correctly I started out with a 1.125 think x 8.00 x 8.00 aluminum. The 8.00 x 8.00 was slightly over size as ordered. Good luck.


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## negativentropy (Mar 14, 2013)

RandyM said:


> I am confused as to how you'd mount the chuck directly to the indexer, I mean I how'd you tighten the studs?:think1:
> 
> Here is what I did, an adapter plate.



Yeah in hind sight I would probably do it your way.  I like that it allows you to move the t-nuts further in on the RT - whereas on mine they are right on the very edge and needed modification.


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## negativentropy (Mar 16, 2013)

So I went back to the local machine shop and they had a left over 6" disc of free machining steel.  I decided to give this another try adding some of the things you guys have done and being more precise this time.

First I turned down a MT2 (which fits in my RT) so that it has a non-tapered section.  This was the hardest part, I think I rubbed the material off more than actually cutting it...  Anyway, this allows me to quickly locate the adapter and chuck to center.  Decided against the set-in-with-spanner-access style, as it would have left to little space for a 3 hole circle and 4 hole circle on the same adapter.  The down side is I had to make custom T-nuts to clear the RT clampdowns.   Never worked with free machining steel - wow, cuts super easy!  Anyway, pictures:


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## Todd (Mar 18, 2013)

if youre table has a morse taper center you can do as i did on my 6" table.  i used the center morse taper by making a long taper with a large flange above it to bolt to the table, above the flange is the threaded portion 2- 1/4" that my chuck is.  this adapter was to many different diameters to be practical to make out of one solid peice, although it could be done.  i used 3 separate peices, 4140 for the taper section, 2233 for the flange and 12l15 for the threaded "spindle nose" .  all these peices were press fit together with some very tight tolerances so they would not come apart.  had to get a 20 ton press to press em as my 2 ton just wouldnt do it.  i dont have any pictures at the moment but i will take some.   doing it this way allows me to not have to indicate my chuck in once i get it off the lathe to the RT.  i just indicate the part in the 4 jaw on the lathe, do the turning then i will move the whole chuck over to the rotary and do the milling, no indicating needed


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## AmericanMachinist (Jan 14, 2022)

I have a 6" four-jaw chuck with through-bolts from the front.   I had been planning to make a 7" adapter plate, to which the chuck bolts (from the front of the chuck), and then using four through-holes in the outside flange of the adapter plate, secure to the rotary table with T-nuts.  After more thought, it seems that I could forgo an adapter plate;  instead use just a round directly for alignment, and use the through bolts in the chuck to secure via T-nuts.  The benefit that is forgone in this approach is the relative ease of lining up T-nuts that are 1/4" or so from the outside of the adapter.... the chuck bolts are 1-1/2" or so inside the OD of the chuck, so more difficult to align the T-nuts.  Am I missing anything otherwise?


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## Alcap (Jan 14, 2022)

I don’t see why you would need the adapter plate either , if aligning the tee slot nuts seem an issue, maybe a pencil type magnet would help or make your own nuts that are long . I’ve see store bought ones but might not have your t slot size. Edit: I think some people use a chuck that they could take right off their lathe and put on the rotary table adapter


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