make sure spindle control is automatic make the material just a bit thicker (0.01“) than it really is choose Shapeoko (1 or 2) as your machine material doesn't matter. Use corian to not be distracted by grain cut settings:

• feed: 75 inches/minute
• plunge: 25  inches/min
• depth per pass: 0.26 (lie by 1/100 inch)

stepover is how much of a diameter to step over as you make a groove wider and wider. Defaults to 40%. Curt uses 80%. 20-40% or 60-80% recommended. Don't use 50% for some reason tabs are thin areas that aren't cut out so the material doesn't slip and slide as you get toward the end of your cutting. Another solution would be double-stick tape for example shape allows you to position exactly where you want your piece.

• Position sets the reference point

1/4 inch cutter can go 1 inch, 1/16 inch could only go 1/4 inch. 2 flutes (or less) google yonico cnc

• go here: http://www.precisionbits.com/spiral/
• then order on Amazon

solid carbide  make sure it can plunge spiral upcut is most common. (this is the place to start but since it cuts “up” there can be chipping