I'm trying to run toolpaths in some high carbon stainless steels to make knife bevels, hardness is about 255BHN. I'm getting my speeds/feeds from Gwizard calc, running a Tormach 770 for my mill, which tops out at 3250 RPM. My surface finish has been less than ideal, and I'm wondering where I'm going wrong.
I'm reducing a piece of stock that's only 3mm thick down to 1mm at where the cutting edge will be, I've not been doing any roughing passes. Because the knife bevel needs to have as smooth a surface finish as possible, I have been using a 1/2 inch wide ball end mill.
How would you approach this problem? How deep would you attempt to cut during a pass?