Burnishing tools

[Kram]

Anyone used them? How much pressure is required, I guess it may be similar to knurlin, and a clamp typemay be easier on lathe than a push type?

Seems quite easy to make using a bearing race/ball bearing
I am guessing that the diamond type need a perfectly smooth diamond but looks like it does not spin, rather just a hemisphere. Expensive I am guessing.

Might try to make a crude one

 

[Kram]

I still need to make one of these. I like this approach, should be easy enough for me to make on lathe, tho I will use round bar. I have some 20mm balls but that will be a bit big.