[MT Stringer]

I use the Keyhole Toolpath Gadget that is built in to Vectric VCarve Pro and Aspire ( VCarve Desktop may not have Gadgets). Once you have it configured with the size of bit you are using and the orientation of the keyhole, it is an easy cut. It saves your settings so it is ready the next time you need a keyhole.

Can't get much easier than that.

Jay

I have used it. Works great.

 

[MT Stringer]

If you have room, you can draw an arc. The bit will enter at one end, cut your desired depth and length, then exit the other end. Then all you have to do is hang your work piece and adjust as necessary to get it plumb. Saw it on a group post on FB.

 

[MT Stringer]

Here is my arc'd keyhole slot. I made it 3 inches long (on an 18 inch dia circle).

Using a keyhole slot cutter, there would be a hole at each end for the screw head to enter/exit.

Edit: Added pictures of actual keyhole slot.