[How do I?] Troubleshooting and Reducing Total Indicated Run out in a New Collet Chuck

RJSakowski said:
1. I would start by checking to see if I can reliably remove and reseat the the chuck. This will determine if there is an issue with the register to the lathe spindle.
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Backing plate? Done. Reseats dead nuts on the spindle shoulder. Chuck? The centering "shoulder" on the backing plate is under cut so the chuck has no tight spots fitting onto the backing plate. To be determined is it under cut enough that it can be tapped into alignment. Right now tapping makes no difference.
RJSakowski said:
2. If the runout remains constant in magnitude and orientation over multiple installs, then I would move on to checking the runout of the backing plate to chuck register. That good, the issue is in the collet socket or the collet.
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I will retest the three positions. If the run-out remains consistent, then I'm going to under-cut the backing plate to chuck centering shoulder by ~ .010 smaller than the largest measured TIR and see if I can tap the chuck into alignment.
RJSakowski said:
3. Check the socket for runout at two positions to determine both radial and angular runout. keep in mind that the effect of angular runout is is magnified the further away from the chuck you are so measured runout of a few tenths in the socket can result in significant measured radial runout at an inch or two from the collet.
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Will have to educate myself on measuring angular run out.
RJSakowski said:
If everything looks good, then the next suspect is the collet itself. This can be evaluated by checking multiple collets and/or by checking in different collet fixtures. Mark everything with a Sharpie so you can determine if direction is consistent.
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I think I'll start with this. I ended up with two Hardinge indexers, one threaded, the other the Hardinge taper & "bowtie" and I have a collet holder for the 10EE (yes, it does beg the question "why?" Answer was for a semi-permenant set up for an Eccentric Engineering Turnado). So too easy to cross check the collet to be sure I'm not chasing a ghost.

Thanks,

Ron
 
HI I purchased 3 of these things all had substantial runout (one .007). they all went back to the seller, I finally thought that it would be better to buy one that I had to machine the backing plate thinking it would match any inherent problems that I didn't foresee. I did that (worrying about my abilities). I marked the backplate to my spindle, I now have .001 runout at 1 inch on a 3/4-inch precision ground rod. I love this thing!
It's nice to have a little luck sometimes.
Rich
 
Again Rich, thanks. It's very good to know the trouble others have had with these things. Helps with the "What in the heck am 'I' doing wrong?!!!" Just may not be me . . . Going to check what return options I have if any after machining the back plate.

The backing plate was re-faced on the lathe and both faces are dead nuts parallel with the spindle shoulder. I used precision spacers over the threaded part of the spindle to make full contact with the lathe spindle shoulder, checked with Prussion Blue. Then backing plate full contact to the chuck checked with Prussion Blue. That narrows it down to the chuck.
 
Check and see if any of the mounting holes are flared, creating a raised surface preventing the chuck from sitting flat on the back plate. I had to clean up all the holes on my 5c and ER40 chucks before I could get the runout down to acceptable levels.
 
Ischgl99 said:
Check and see if any of the mounting holes are flared, creating a raised surface preventing the chuck from sitting flat on the back plate. I had to clean up all the holes on my 5c and ER40 chucks before I could get the runout down to acceptable levels.
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Ah! Will do, thanks!
 
Prior to leaving for an afternoon of fishing, I went down to the shop to check my 5C chuck. I was measuring .0025" to .0031" TIR at the chuck with a 1/2" collet, a 3/4"collet, and a 1" collet. The orientation of the maximum was essentially the same for all three collets. I also checked for angular runout and it was less than .001" over a 6" distance. Removing and remounting the chuck caused no change. The conclusion was that the observed runout was nearly all radial and was consistent.

I loosened the bolts mounting the chuck to the backing plate and found that I could change the runout magnitude and direction by tapping with a brass bar, using a dial test indicator to track the progress. I snugged up the bolts and tapped the chuck body to obtain zero runout. Then I further tightened the bolts and repeated the process. Finally, I tightened the bolts securely and checked the runout. My final TIR is less than .0002" and that is good enough for me.
 
RJSakowski said:
Prior to leaving for an afternoon of fishing, I went down to the shop to check my 5C chuck. I was measuring .0025" to .0031" TIR at the chuck with a 1/2" collet, a 3/4"collet, and a 1" collet. The orientation of the maximum was essentially the same for all three collets. I also checked for angular runout and it was less than .001" over a 6" distance. Removing and remounting the chuck caused no change. The conclusion was that the observed runout was nearly all radial and was consistent.

I loosened the bolts mounting the chuck to the backing plate and found that I could change the runout magnitude and direction by tapping with a brass bar, using a dial test indicator to track the progress. I snugged up the bolts and tapped the chuck body to obtain zero runout. Then I further tightened the bolts and repeated the process. Finally, I tightened the bolts securely and checked the runout. My final TIR is less than .0002" and that is good enough for me.
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RJ, thanks for taking time out of your fishing, the information is appreciated! I am responding without little to report so you don't think I'm an ingrate. With some 5/8" O1 and collet on the Hardinge, I had .002 TIR. Not great. On the chuck with "tapy tap tap" :) I got .005 TIR on two bolt holes, ran out of time before chores called to do the 3rd. Decided to use my Zoro coupon to order 1" & 5/8" O1 and a 1" new collet. The reason being is if it's still out maybe I can learn something by supporting the chuck on the 1" on a dog plate and support the end with the TS to see what I get on the chuck to backing plate face.

More to follow.
 
A thing to remember is that O1 drill rod isn't necessarily straight to a high degree of precision. Specs. that I have seen can run as high as +/-.005". Rather than assume that it is, you should rotate the rod by 90, 180, and 270º in your collet to verify that the TIR doesn't change in either magnitude or direction.
 
Thanks for the reminder, just like clyinders. For trying to establish a baseline I expect to use <.5" stick out in the indexer mounted to the mill table, I should be able to do a rotation. Then I can check the collet in 3 places on the chuck. Hopefully.
 
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