Whats The Deal With My Bearings

[jason30809]

a while back I posted about extreme vibration anytime I tried to part of with any material from 6061 all the way to 316. this problem just started out of the blue one day about a year after I acquired it. I had already checked and retightened all gibs and insured the tool was sharp and centered so I was told that my bearings might be the culprit. recently I recently noticed when I set my cross slide to take x depth of cut I always came up short in the amount it took off so I put a 1.5in x 10in piece of round bar into the 4 jaw and gave the push pull test and came up with around .012 of run out. My problem is that I disassembled the headstock yesterday and my bearings at least to me appear to be in decent condition. How do I know if my bearings need replacing and if they don't display the signs of damage or excessive wear can anybody help lead me in the right direction to figure out this problem? I really appreciate every ones time. by the way my machine is a atlas 10f with Timken bearings. I have also heard of "adjusting" the bearings on the spindle. Is this possible on my machine

 

[wa5cab]

Jason,

After you wrote that the spindle nose had 0.012" os side to side movement (technically, that's not the runout), I was assuming that you had either a 6" Craftsman 101.07301 with worn out sleeve bearings or a 10" or 12" with worn out babbit bearings. With bearings in decent shape and properly adjusted and no damage to the spindle where the bearing cones fit, a Timken bearing headstock will always have zero side to side movement. In all probability, you just need to properly adjust the bearings. That doesn't, however, mean that you are going to find that you have zero runout. But it will be much lower, how much lower probably depending upon the condition of the chuck holding the test piece. And how close to being actually round and straight your test piece is.

If you haven't already done so, first read the H - M Downloads instructions which you will find above in the "sticky" area. Then go to DOWNLOADS, go to the Atlas section, and download the Atlas Technical Bulletin on the 10" headstock. It will tell you how to disassemble, re-assemble and adjust the back gears and spindle bearings.

As for as how do you know if your bearings need replacement, most of the time they don't. Unless they have been allowed to rust, or unless a PO ran it without every oiling it. Inspect the rollers, cage and cup for signs of wear or other damage (pits, scratches or grooves) . If you find none, put the headstock back together and adjust the bearings. Then check the runout on the register (unthreaded area between the spindle flange and the beginning of the threads) and on the right face of the flange.

 

[jason30809]

thanks so much, I have spent hours using every search term I can think of to find a video or guide to adjusting or replacing these bearings in my lathe so thanks for the help. I would go nuts without a working lathe.