That should work... better if you lay the board onto the bit in the middle of the mortise, then go side to side to your guidelines.
Also, to control the depth of cut, NOT doing the complete mortise in ONE pass...
Adjust your bit ht. to the desired depth.
Use some slotted pieces of 1/8" plywood over the table & bit, to raise the workpiece.
Make a cut.
Remove one piece, making room for another 1/8" cut.
Make a cut.
etc. until the last cut is without any spacers.
By doing that, it's easier on the bit, the wood, the router, and you will maintain the bit position to keep a clean cut pass after pass, etc. |