Old Buck Chuck Repair

piper184

H-M Supporter - Gold Member
H-M Supporter Gold Member
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Dec 16, 2021
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The old 3 jaw chuck on my SB10K started jamming up. Even when backing out the jaws. Thought it was just swarf but couldn't get it running right even after cleaning. Time to tear it apart for "deep cleaning".

Then I noticed the pinion was broken out at all four corners. It was pretty worn when I got it a year ago but it finally broke.
The chuck is likely a 1970's vintage as is the lathe and well, no longer supported by Buck.

Internet searches and inquires turned up Kalamazoo Chuck Manufacturing which still makes parts for and supports the older Buck Chucks, and probably more.

The nice lady (Dawn) at the other end of the computer was really helpful and got me set up with a new pinion and chuck key. I probably didn't need the key but was so grateful for the support I bought a new one anyway. The outside jaws were missing from this lathe when I bought it and Dawn said they can even make me a new set of jaws and gave me a price. All the prices seem high at the onset, but when you think about what it takes to make these parts it really isn't that bad. Especially compared to tossing the chuck and buying a new one.

Cleaned, lubed and reassembled the chuck is once again smooth as silk. Since it is the acu-tru it was easy to dial back in. Now running with half a thou indicated with repeatability of about .001". I'll take that any day for an old machine for a rank amature like me to play with!

I have no connection with KCM except as a happy customer.

Hopefully this will help someone else with an orphan Buck Chuck.
 

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Could br that a worn chuck key was what broke the pinion.
 
I figured that was probably the case. The key that came with it was a new looking import that measured exactly .250 square. But it fit loose because the pinion was worn. I couldn't find anything that fit properly so continued to use it.

The new key fits the new pinion perfectly however the import key won't go in. The corners don't have a large enough radius and the darned thing is too hard to file. It does fit my 4 jaw just fine so I will continue to use it for that.

I'm pretty sure the pinion gave way under my hand but I honestly didn't think I put that much pressure on it. The key handles are short and I never use anything but my bare hands.

I was just happy to get it fixed without having to buy a whole new chuck.
 
Another happy KCM customer here! They re-ground a little set tru 6" 6-jaw( including the bell mouthed jaws ) for me, and did a perfect job. Good people IME.
 
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