My not so mini English wheel

[Brad93]

I’ve never quite got my head around hardness measurement there seems to be a lot of different scales it’s measured by but that sounds plenty hard enough…

Is there an upper limit for what you can turn?

70HRc above can only be touched with abrasive wheels, probably CBN or diamond really.

 

[Brad93]

50-56HRc you can do with CERAMIC.

Past that CBN for true hard turning.

After that it's abrasive

 

[Martin Hocking]

Thanks Brad that makes it clearer.

I’ve never really seen hard turning just had a quick look on the tube because I was wondering what the swarf was like what with the material being so hard.

Blimey! You wouldn’t want to be doing that in your pants!

Makes a bit more sense now.

 

[Stueeee]

I have machined ball race bearings using CBN (Cubic Boron Nitride) inserts on one of my lathes. The swarf comes orange/yellow but the machined finish was very good.

This was the first tentative cut, like a lot of insert tooling bigger cuts give an even better finish