Hello Forum,
I thought I would share my experience of CNC milling on my Tormach 1100 PCNC Series III some slots in a castellated steel nut. I bought a nice Harvey tools 1" woodruff cutter with .0625 r (.125) diam, Part # 937362. I was machining 4041 steel. I contacted Harvey and they were nice enough to help with some speeds and feeds as follows.
SFM: 200, RPM 764, Chip Load: .00138 IPT, Feed: 6.33 IPM, DOC: full at .125" WOC .080. (3 passes)
I tried these on a sample of 6061 to see how that would run but found it was very noisy. I felt I was getting a little chatter. Long story short I kept up with adjusting the speeds and feeds, # of passes and lead in and lead out until I got a good formula and ran the part in steel. The results were very good and so here is what I ended up with.
SFM: 220, PRM: 850, Chip Load .00138, Feed 4.00 IMP, DOC: .125, WOC 0.020" with 8 passes.
Hope this helps someone trying the same operation on their own.