[How do I?] 10" Buck chuck centering question

[Marcduper]

Good afternoon all,

I have a nice 10" Buck chuck with a L1 mounting system. If a mount the chuck and center the work peice using the Buck adjust system and indicate to zero, the chuck body runs .032" out. This is a little to much for vibration and such. I was using a 1.5" known true work piece for indicating. What is wrong? The chuck has been cleaned throghout. The jaws are good and in the right place. Any tips would help. Thanks.

 

[projectnut]

When you say "1.5" known true work piece for indicating" what exactly are you using? I've found it's best to use a hardened dowel pin. I have several different sizes and lengths from McMaster just for this job. The most commonly used one is 1" in diameter and 4" long. The diameter tolerance is .0001" to .0003"

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[mksj]

I have turned down chuck bodies that have not run true, but that may also lead to balance problems. It could be that the jaws jaws are not running true to the chuck body, or in the wrong slot, etc. W/O some pictures, the mounting system, the condition of the chuck/jaws it is all just a guess. If this is a set-tru type chuck, I would be surprised if you have that degree of adjustment to have the body that far off from the jaws. You do not necessarily need a precision rod to center the chuck, just that the +/- swing of an indicator is the same in both directions. I do use some precision ground rods from McMasters in 1/2" and 1" ground rod, and use the +/- swing to verify center and skew.

 

[benmychree]

I would be considering recentering the chuck body and then regrinding the jaws to true center, of course then every time you need to turn a workpiece to a concentric diameter you may need to readjust the chuck, if the cuck proves to be worn beyond usefulness, a 4 jaw chuck may prove more useful for precise work.