Turning a bearing race?

[dkmc]

Couple questions.......what's the typical hardness of a bearing race? My guess is C scale 60-64? And what insert would be best choice to machine .010 smaller on OD? Manual engine lathe, not cnc.
TIA

 

[Zeuserdoo]

Id try to find a CBN with little to no edge prep for only taking off .010. Sumitomo makes them.

 

[redlee]

Ceramic works well.

 

[Conrad Hoffman]

Don't know about inserts but some surprisingly good thin section bearings are made from 52100, hardened and then turned. Not quite as good as ground, but close.

 

[edwin dirnbeck]

Couple questions.......what's the typical hardness of a bearing race? My guess is C scale 60-64? And what insert would be best choice to machine .010 smaller on OD? Manual engine lathe, not cnc.
TIA

I have done it a few times. I think that I might even have started a thread and posted pictures on this or the other forum. Any old carbide will do, Turn it as fast as your lathe will go use a sharp pointy insert . If you are trying to turn the O,D, of a medium size ball bearing such as a 1 1/4 od bearing, Chuck up a peice of 1 1/4 cold rolled steel. Face it and drill and tap a 3/8 hole. Clamp it with a Special heavy washer that only touches the outer race. Indicate it in and tighten The clamp bolt. Take a cut ,sharpen tool and repeat,repeat.Let it cool and finish the final size with a stone or 220 emery cloth against a file. Edwin Dirnbeck

 

[ratbldr427]

I have cut quite a few. Any carbide will cut. The chip will be stringy and red hot. I have made a lot of punches out of old races to cut gaskets and brass shim.

 

[hvnlymachining]

Bearing races are easy to turn with ceramic, which isn't hard to find as industrial surplus. We use kennametal with great success. I've done short run bearing race modification (48 pcs) with a single corner of an insert. The "chips" (more of a constant fine string) come off glowing when done right.

Plenty of videos on the net of it being done.

 

[chipss]

Bearings are typically Rc 61-62.
You can machine it but you will need some very accurate fixturing. Cutting this hard material requires a lot of tool pressure and you will distort the part unles it's very well supported.

 

[hvnlymachining]

Bearings are typically Rc 61-62.
You can machine it but you will need some very accurate fixturing. Cutting this hard material requires a lot of tool pressure and you will distort the part unles it's very well supported.

Maybe it was just because of the sizes I worked with, but I never had a problem with either distortion or high tool pressure. But usually worked under 3" diameter. Even turned a couple of tapers.