# Acceptable Runout On New Chuck For Pm



## Buggy Chief (Dec 5, 2016)

Just bought an Asian 5c D1-4 cam lock chuck.  What is acceptable runout.  I am getting .002" - .0025" at base (next to spindle), at taper and inside collet holder...pretty consistent, but didn't know what is considered acceptable?  Finally, how would you adjust to get less runout?

TIA


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## tmarks11 (Dec 5, 2016)

What runout do you get inside the spindle nose(with no chuck)?  What runout do you get if you chuck up a piece of round stock on the stock itself?

How expensive of a chuck was it?


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## Bob Korves (Dec 5, 2016)

Like tmarks11 said, don't check the collet chuck parts, check a known straight, round, and parallel part, like perhaps a dowel pin, mounted in the collet chuck and see what you get then.  Try different diameters, because collets also have runout.  Also, does the collet chuck have an integral D1-4 mount or does it have a separate back plate that mounts to the spindle?  Make sure that the back of the back plate or the integral D1-4 mount is sitting dead flat against the spindle when it is tightened down.  Check it carefully with a light from behind.  Also make sure that there is at least a bit of interference fit between the spindle taper OD and the collet chuck or back plate ID taper.  If the taper fit is too loose you will have radial runout.  If the chuck is not pulling completely down on to the the spindle face it will not be square with the spindle and you will have a wobbling runout.  You want to be snug on both at the same time without gronking down on the square keys.  Also make sure the lathe spindle itself does not have runout on the taper or on the chuck mounting face.


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## jbolt (Dec 6, 2016)

What is the run out at the inside taper of the chuck?

Also mount the chuck in each of the three possible positions and check at each one.


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## Buggy Chief (Dec 6, 2016)

Thanks for all of the input.  I checked the runout and the spindle is nearly 0.000".  I adjusted the cam lock studs as one of the three was locking at a different position.  Didn't affect too much, but now the runout on the inside of the chuck taper is .001".

Again, I appreciate all of the input, but back to the original question...What is acceptable runout in the home hobby situation to most?  Thanks again.


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## T Bredehoft (Dec 6, 2016)

I think you'll find that most of us get testy if it won'd come in under .003. You're .001 is fine. None of us work for NASA on the side. A collet setup, with a dowel pin, should be expected to be nearer .000 than .003, however.


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## jbolt (Dec 6, 2016)

If you don't have one I would recommend getting a test indicator that reads to ten thousands. When measuring things like run-out you need that level of precision. 

I'm not sure what Matt has speced for your machine but I would guess the spindle run-out should be 0.0005" or less. Most of the import 5C chucks I have dealt with claim a total indicated run-out (TIR) around 0.0005" but in reality have been up to 0.001". Same for the import collets. When you start stacking all the errors it can add up unfavorably. By testing the chuck at different positions on the spindle you find the least amount of run-out and mark the chuck for reference. 

Expensive Hardinge standard 5C collets are only guaranteed a TIR of 0.001". Their special accuracy collets are speced to 0.0002"

If you are getting 0.001" I would consider that within the accepted tolerance of the quality of chuck you have. To do better you get into the more expensive adjustable chucks.


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## Buggy Chief (Dec 6, 2016)

Thanks for the input and helping out here!!


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