Cutters

[frank_hav]

We want to try some different cutters for 18mm Baltic Birch. does the 1 flute really cut faster then the 2 flute. I know Onsrud says they do but chip load versus chip cleareance seems like that would be a stretch to me. Lokking to cut full depth with 1/2 dia. traveling around 7 inches per second. What do we think. Any help for another cutter brand might help also. Onrud #'s we are looking at are 52-360 and 63-360.

Frank

[gpari]

Unless you can live with some deflection induced error in your final parts, I don't think you'll get single pass at 7ips in 18mm BB. In my experience the shopbot is not stiff enough to run that fast, single passing something as hard as BB.

Try cutting two squares then putting them next to each other. If you climb cut, the parts will be high in the middle, if you conv. cut the parts will be hollow in the middle of the run.

Just depends on how accurate you need your parts to be.

Gabe
www.socalteardrops.com (http://www.socalteardrops.com)

[frank_hav]

Gabe,

I agree, I should have made it clear that this was being done on our Onsrud CNC, not the bot. On the bot I know I'm good for about 3 max.

Frank

[Brady Watson]

Frank,
It sounds to me like you need a compression spiral. It is made for cutting full depth, but your software should allow for a ramped plunge/lead in to reduce stress on the bit & spindle. I know Onsrud (and others) sell several variations of the traditional compression spiral grind. A chipbreaker/finisher might be an appropriate bit for this application.

-B