Measure and mark where you want the keyhole cut on your frame, switch plate or keyhole cover.
Determine how deeply you want to penetrate with the router and make a note.
Set the height of your router to the desired height by adjusting the height band on the router.
Loosen the router collet with a wrench and insert the keyhole bit until there is approximately 1/8 inch between the collet and bit.
Tighten the collet with a wrench.
Turn on the router and gently lower it to your marked keyhole. The keyhole bit will cut at your designated height.