The keyhole toolpath has been in CC for some time. I use a Frued 70-104. Go to the OEM website to get the exact specs of your keyhole bit. Be careful about F&S from the OEM. For instance the Freud website has fantastically high F&S. I think they are calculating for an industrial CNC and not a hobby CNC. Simply substitute your bit measurements for what I have and also your unique tool number.
The basic operation is to draw a circle the diameter of your keyhole bit. Then tell the toolpath how for to plunge forward. Super easy. The keyhole toolpath plunges full depth for the screw head and then moves forward the amount you set in the toolpath. Then the bit reverses and plunges back out the entry hole. Just make sure you plunge far enough to have some meat in the wood where the screw will actually hang on the wall. If you make it too thin the keyhole could break out.
The keyhole bit diameters are as follows. The diameter of the keyhole bit at the bottom. Then the thickness of the large bottom of the keyhole bit. Then the shaft of the smaller part of the keyhole bit. So you can calculate about 1/8" of meat in the smaller slot and likely about 1" of distance the keyhole will move forward.
Here is my custom tool database for the keyhole bit.
| number | vendor | model | URL | name | type | diameter | cornerradius | flutelength | shaftdiameter | angle | numflutes | stickout | coating | metric | notes | machine | material | plungerate | feedrate | rpm | depth | cutpower | finishallowance | 3dstepover | 3dfeedrate | 3drpm |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 701 | Freud | 70-104 | 701 Keyhole | end | 0.39 | 0 | 0.25 | 0 | 0 | 2 | 0.125 | 0 | 10 | 60 | 16000 | 0.4375 | 1 | 1 | 60 | 16000 |