I have recently plunged into the world of CNC (horrible pun), and have access to an Omnitech Selexx CNC for guitar building. I have all of the CAD work done, and am finalizing CAM setup and have been working through speeds and feeds with various resources on the net (GWizard calculator, websites, etc). I can find CPT values easy enough based on the wood I am milling, but am struggling to nail down spindle speed and SFM. For example, I am using a 1/4" Vortex endmill (1232) for some roughing and pockets. Based on what I have read, I should be fine with a DOC of < .25 inch. Here are some sample calcs I have run:

SFM: 1042
Cut Depth: .22
Spindle RPM: 13402
CPT: .010 ipt
Feedrate: 206 ipm

Based on the specs of this machine, these seem reasonable, but the thing that throws me off is that I can change these numbers wildly in the calculator, so I dont know what is really a good starting point. Thanks for your time and advice!