Don’t know if this will be helpful, but I searched all over for a way to cut t-hole slots for hanging pictures and frames. It needs to plunge to a quarter of an inch, and then nibble forward, back up, nibble forward, back up, etc. This is if you don’t want the hassle of first cutting a quarter inch pocket, then following up with the keyhole bit. This code is for 1/8" depth of cut slot cutters. The bottom of the cut is only .25" deep so this is safe for .5" material.

This code slows the plunge to 5 ipm, and overrides the feed rate to 10 ipm. It goes .1" forward, goest back to zero, and creeps forward another .1" until a 1" slot is created. It then returns to zero and lifts out the bit.

Worked great for me. You just zero out right over where you want the circular hole to be. The slot will be cut up (away from you) from there. My machine is set for inches. You may need to do a little translating. And you’ll need to secure your material a little better than double sided tape.

GCODE:

T1M6

G17

G0Z1.1000

G0X0.0000Y0.0000S12000M3

G0X0.0000Y0.0000Z0.2000

G1Z-0.2500F5.0

G1Y0.1000F10.0

Y0.0000

Y0.2000

Y0.0000

Y0.3000

Y0.0000

Y0.4000

Y0.0000

Y0.5000

Y0.0000

Y0.6000

Y0.0000

Y0.7000

Y0.0000

Y0.8000

Y0.0000

Y0.9000

Y0.0000

Y1.0000

Y0.0000

G0Z0.2000

G0Z1.1000

G0X0.0000Y0.0000

M30