On 12/14/2012 1:03 PM, Greg Guarino wrote:
On 12/14/2012 1:54 PM, Peter Bennett wrote:
On Thu, 13 Dec 2012 21:38:15 -0600, -MIKE-
wrote:

On 12/13/12 8:19 PM, Peter Bennett wrote:
My router dado jig doesn't need guide bushings or a top bearing bit -
it guides the router base.

each side of the guide consists of two pieces - a wide piece of 1/4"
plywood that the router rides on, and a (straight!) piece of 1/2"
plywood, or similar piece of solid wood glued on top.

Before the first use, run the router along the jig with the base
against the 1/2" board, so the router bit can trim the 1/4" plywood to
the correct size.


The jigs we're discussing adjust for the thickness of the board that
will go into the dado.
If I understand correctly, all your jig does is allow you to line up
perfectly with a marked line, like a circular saw rip guide.

No - my dado jig uses two pieces as described, joined similarly to the
Woodwhisperer's dado jig, but it uses the router base as the guide,
rather than requiring a guide bushing or a bearing on the bit. (maybe
I should take a picture of it, and post it somewhere...)


Now that sounds like the idea I had. The two guides are separated by a
distance equal to the diameter of the router base plus the thickness of
the stock to go in the dado, right? The router base rides along one
guide first, then the other? I figured if I did this the first pass
would cut a dado in the pieces that join the two guides together,
thereby giving me registration marks to line up the cut with. The
pattern bit idea sounds even more foolproof though, at least to my
untutored ear.

the problem with this is that the bit usually isn't dead center in the
base. if you twist the router on it's trip across the board, you'll get
a wavy edge to the dado.