Blob
Hot Rolled
- Joined
- Apr 7, 2007
- Location
- Scotts Valley, CA
I recently bought a used Jacobs Rubberflex chuck and collet set, and I wanted to relate what happened. I found a 91-A6 hand wheel chuck that had a 1-1/2 - 8 adapter already on it, just what I wanted for my 10K. However, when I screwed it on the spindle, the runout was about .010" - not good. I had assumed that the adapter would probably need to be machined on my lathe, so I removed the chuck from the adapter and re-machined the taper and mounting flange. Problem was, with the chuck re-mounted on the adapter the runout was still about .004". Took the chuck back off and disassembled it - what a dirty mess. I don't think it had been cleaned since it was new, but at least there was no visible damage, so I cleaned and lubed it, put it back on and - no improvement. Still about .004" out at the taper. I ended up using the toolpost grinder to re-grind the collet taper and got the runout down to near zero, so it turned out OK, but it was more than just runout - the taper was unevenly worn, with a low spot in one place. Moral of the story - if you get a used chuck that was run hard and put away wet like I did, don't be surprised if it doesn't perform well. I'd be up a creek without a paddle if I didn't have a grinder to fix the taper. So if the choice is between a used chuck without a known history and a new one, sometimes it might be a better idea to spend for a new one, unless you have the time and means to fix a worn chuck - it took me most of the day. On the bright side, the chuck is very well made, easy to use and is now very accurate. Anyway, buyer beware.