today's project; rorary table chuck mount

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liveaboard
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today's project; rorary table chuck mount

Post by liveaboard »

This has been in my head for too long, and I needed to get it done so I could forget about it.
I have 4 chucks for my lathe, and an 8" rotary table for the mill...

I started by cutting a locating groove into my rotary table, and a matching one in the lathe spindle clone I made years ago for making chuck back plates. Then a centering ring.
Then I light pressed it into a plate with some loctite before facing the bottom.
rotary table adaptor 1.jpg
It took a couple of tries; I had it zeroed and it was concentric, but I had a wobble, and I could hear Harold in my head; "soft jaws!".

I was too far along to start a whole learning curve, so I made a one use mandrel instead. This took me several hours; but it worked.
rotary table adaptor2.jpg
Now there's just 0.03mm runout, and that's as close to good as I can hope for.
rotary table adaptor3.jpg
I spaced the holes so that the adaptor can also bolt to the mill table, so I can use a lathe chuck as a vertical vise. I don't know if that will ever be any use but it didn't cost extra.
rotary table adaptor4.jpg
Russ Hanscom
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Re: today's project; rorary table chuck mount

Post by Russ Hanscom »

Always opt for maximum flexibility/options, you will use them someday!
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Harold_V
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Re: today's project; rorary table chuck mount

Post by Harold_V »

Yep! What Russ said. It is impossible for anyone to know what project they may face in the future. If you can obtain or build tooling that is adaptable, so much the better!

Nice job!

Do explore soft jaws. They are the magic bullet for holding.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
pete
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Re: today's project; rorary table chuck mount

Post by pete »

Some good thinking outside the box Mark. But indicating the chucks O.D. won't tell you much. It may not even be fully concentric to the jaw tip C/L. Yes it should be very close but not all chucks are. Pull the jaws and spin the chuck under one full rotation while indicating on the chucks face. That checks your axial run out. I'd also use your mill table as a rudimentary surface plate and indicate the chucks face at both sides of X and the same in Y to be sure it's in fact square to the table. Then do the same with a variety of part diameters held in the jaws. That will check your average radial run out. While my Vertex dividing head came with a fairly well made 6" 3 jaw, it's in reality almost useless since most items you'd use a rotary or dividing head for require much better part centering than any average 3 jaw can repeatably provide. So unless you remove the whole chuck from the lathe with the work still in the chuck and remount it to your R/T, your forced to shim the work in that 3 jaw to compensate for it's inaccuracy or use a 4 jaw independent and again indicate the work in. And for some larger work pieces using a face plate on your R/T might still work better than any chuck.

And yes, being able to mount the chuck to the table as a work holder will be handy. At that point concentricity isn't important since your then indicating the mills spindle in X,Y to the part C/L and using coordinate off sets for whatever else your doing. But again the chucks face and it's actual squareness to the table is important since it's then a datum reference surface and if it's not correct then your parts won't be. For rough work none of this may be important, but it's tough to try and add accuracy later for anything that does require better. And your lucky you have that 8" R/T. I bought a 6" for my smaller mill. Now with the larger mill it's really too small for most work as there's little room for strap clamps etc.
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liveaboard
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Re: today's project; rorary table chuck mount

Post by liveaboard »

Even the 8" has little space for clamping; it was the biggest one that could be posted though, and I was / am unable to collect from the distant places I buy from. It was a good score, no one else bid as I recall.
I think it's a good size for me, I can still lift it by hand and it nearly spans the width of the mill table.

The chuck is not particularly concentric for holding, but the body is concentric to the bore. I know that from making the backplate.
However close it is, I think this is as close as I'll ever get it.

I have two 4-jaw chucks as well, so my main concern is that the jaws are reasonably close to perpendicular to the table.
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