I need to make 3 collars, with 11mm bores. The material is stainless. I predrilled the bore to 10.2mm. Made a D bit out of silver steel (drill rod, 1.2210, 115CrV3). The bore end is 10.98mm, and the half thickness 5.48mm. Hardened and tempered back to deep straw colour.
The front cutting edge as ground on the Clarkson to 10° front cutting angle, and 7 front relief. Then honed on the top and front faces.
When I tried it on a collar, it deflected and made a mess.
Any suggestion for correcting the geometry would be appreciated.
Mark