I am installing a pocket door. One option for the bottom door guide (keeps the bottom of the door stable when sliding open/close) is to cut a groove 5/16” wide by 1” deep on the bottom of the door. The groove will need to be straight and on center of the 1-3/8” thick door. I am searching for a bit that will allow me to lay the door horizontally on saw horses and run the router vertically along the bottom of the door. Does anyone know of a bit that will allow me to do this? My other option is to make a jig to use a 5/16” mortise bit. But, I prefer just to use the router. Thanks!