If you're using 3/4" thick stock for your door panels you'll want to use these Back Cutter router bits. They cut a quick rabbet in the back of 3/4" thick door panels allowing you to keep the face of your raised panel flush with the face of the rails & stile door frame. You'll be left with a 1/4" thick tongue on your door panel which will fit perfectly into the 1/4" groove made by your stile router bits.