I was recently watching the Sommerfeld video on the tongue & groove
cabinet assembly method. In that video Mark Sommerfeld mentiond
dropping a grommet in the hole in the shaft of the router, to make the
tongue bit bottom out at the exact same depth as the groove bit, thus
allowing you to change from one bit to the other at will without
having to fiddle with depth adjustments. (after the initial depth is
set, of course)
Wondering if this would work with my Jesada door making set, I cut a
piece of slightly undersized dowel and dropped it down in that hole.
Then the sticking bit was loaded, the depth adjusted, and a cut made.
After that, I removed the sticking bit and replaced it with the coping
bit and made that cut without changing the depth at all.
Voila. Perfect alignment. The faces of the two pieces came together
perfectly flush. No more laborious and shape-changing sanding on
Various routers will require different methods of achieving this.
Mark Sommerfeld's router must have a very shallow hole in it to
require only a grommet. My Bosch has a hole thats near 3" deep so
something else was required, hence the dowel.
Another thing that may affect this is whether or not the cope/stick
bits are made with the correct shaft lengths for this method to work.
At any rate, its worth a try and will save a lot of time and
aggravation for you if it does.