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machining 52100 (bearing race)


Hot Rolled
Mar 11, 2019
I have a few bearing races to quote but I have not machined 52100 before. I know a lot of bearing races were ran on multispindle screw machines in the past, but the prints say they cant have chatter on the O.D. So i suspect they have had issues in the past with it. I would think a form tool may chatter a bit but a swiss sliding head lathe could single point it without chatter marks.

I know there is a big industry relating to bearings and with a little more experience I might be able to put some of these jobs on my Brownies. QTY's are right at 5k,10k,15k per part #. I would hate to say no to them.

The material would be cold drawn annealed when its machined. what is comparible to this material as far as machinability?




Apr 1, 2022
Are you just rough machining them, then send to be heat treated, then sent to a grind shop for finish? I couldn't imagine a bearing race would just be turned.

If it's annealed I would think it should behave something similar to 4340, but that's just my speculation I've never machined it personally. I'm sure someone more knowledgeable will chime in.
Apr 14, 2018
Totalitarian Ruling Capital, EastAsia
I have a few bearing races to quote but I have not machined 52100 before.

It turns fine but is hard on tools and doesn't like to break a chip. By hard on tools, I mean wear. Carbide is not that much of a problem but if you are using hss in a screw machine, more so. I never had problems with chatter but chip control, for sure.

Once you get it dialled in it's fine but getting to that point can be interesting.

Quoting that many on a first try is going to be exciting :) If you quote for 4340 then add some for extra hassle, should at least break even. 20% maybe ?