[John 55]

I can't lower the cuck pressure enough to not deform my part. I have a 6 in. ring in pie jaws and when I lower the pressure too much, the chuck won't move and when I raise the pressure for the chuck to close, it deforms the part. Any advice? Thanks

[underthetire]

Stock chucks on all machines are junk for holding thin wall parts. Sorry to be blunt, but it's the truth. Thats why the SMW chucks were so nice, they took very little pressure to clamp and stay clamped even at high RPM. You might have to take the chuck off and clean/ lubricate it, might help a little bit.

http://kitagawa.com/wp-content/uploa..._-web-blue.pdf

This has all you want to know about chucks. Look at the clamp force drop off chart. It's an eye opener.

[fizzissist]

http://kitagawa.com/wp-content/uploa..._-web-blue.pdf

This has all you want to know about chucks. Look at the clamp force drop off chart. It's an eye opener.

GREAT link on chucks!!!!

[underthetire]

Thanks, found it a couple days ago. It amazes me how often people overlook chucks. Most shops buy new mill vises every few years, but never replace lathe chucks or maintain them. A 20 lb part spinning 4k rpm on a old chuck scares the hell out of me. I've seen people hurt, maimed, and killed by part launches.