[Spinnetti]

Hi all. Cut my first part on my series III today, and would like to improve surface finish. Can you share some tips?

Its a tiny part about .4x.7in. made from .125 thick 6061, fully contoured on the outside.
- Kress 1050w motor
- .125 2 flute solid carbide cutter
- 11in/min feed
- ~7000rpm speed (not sure, don't have a tach to check it, but minimum speed of the motor is 5000rpm)
- Flood coolant, Tormach variety at 20:1 dilution
- Cutter is "choked up" into the collet right to the start of the flutes to minimize unsupported length
- Climb cut

I experimented with feeds from 2-12ipm, and speeds from 6000-15000 rpm, coolant, no coolant, and air blast for coolant, but all the parts look about the same. Seeing a bit of taper top to bottom, tooth marks, and some recutting/burnishing. On my "homemade" Grizzly G1106, I got pretty nice finishes with the same cutter at about 3000rpm and ~2ipm with mist coolant. Would like to ramp up the speed a lot, but keep a decent finish. Its not horrible, but would like to get a cleaner cut I don't have to hand sand to look "eyeball" decent.

Its hard to get a natural picture of something this small, and I exaggerated the finish in software, but you'll get the idea. The top surface is a good finish that I'd like to match. The wall thickness at the hole is .025 to give you some scale.