Cutting 22 guage zinc?

[wespor]

I don't have a lot of experience with cutting metal beyond aluminum. Usually turn down most metal projects but this one gave me pause to consider, it's very thin zinc. Is this doable on my spindle, if so what sort of bit?

[Brady Watson]

Similar to aluminum. Use vacuum for hold down as screws will distort the material. This is of course, if it is truly 100% zinc and you are not talking about galvanized steel sheet metal like the kind used for HVAC ducting...

Same rules for all metals applies - always ramp into the cut, NEVER straight down.

Use a single flute spiral O bit, 13k-15k RPM, MS,1.2,0.7 to start. Adjust accordingly.

If the bit gums up, consider cooling the bit with 15-20psi of compressed air. You can make a simple air cooling setup using a few 90s and a Husky blowgun kit where you use the football inflator as the nozzle. An 8" pipe (1/8" or 1/4" NPT) can be used and secured to the Z. Screw a compressed air coupling onto the end.

If you have to 'drill' holes, you just use a smaller O-flute than the diameter and do a spiral ramp inside profile cut as drilling would violate the plunge straight down rule...and most O-flutes are NOT center cutting so they are made to be ramped down anyway.

-B