[skray775]

Last week I ordered a couple of Hertel 2 flute, high helix, HSS, coated end mills to try out. Today I needed to run a batch of these parts and I was really baffled by what I saw.

At first I thought my machine was out of tram or some other problem had cropped up but then I tried Maritool 3/8" endmill and it was much better. The machine is a RF 45 type bench top so while it is not a perfect machine it works well.

My question is what would cause that type of surface finish? I have used plenty of 2 flute endmills and have never seen anything like that?

From left to right in the picture: Hertel 2 flute 1/4", Hertel 2 flute 3/8", Maritool 3 flute 3/8" carbide. The speeds and feeds were set using Gwizard and previous experience. Material is 6061-T6, I hit the parts with a bead blaster so you could see the marks.