Based on a YouTube video demonstration by The Wood Whisperer, I drew plans and built my own version of an exact width dado jig. I have been using it for a couple of years and it works great. Mainly I have used it to cut dadoes for cabinets pieces...50 + cabinets and counting!

 

Same basic principle as Marc's, one side is stationary and the other is adjustable. Just place a representative piece of material in the jig and cinch snug and tighten the knobs. Then, using a 1/2 inch pattern bit mounted in a router, rout the dado. I usually make my dadoes 1/4 inch deep so two passes will do nicely.

 

I made the jig large enough so base cabinet sides can be cut as well as uppers. And, if you are only needing a one off dado job, you could always make a stationary sides and cut away. Simple template routing.

 

Also, when I needed to make a stopped dado, I added a stop block with a screw. Worked well also.

 

I hope you like the plan. Use it and have fun.

Mike

 

Edited June 26, 20178 yr by MT Stringer
typo

I made mine like yours. Extra wide for cabinets.

Hey Thanks Mike for the detailed drawings. Great post! Just a suggestion while Edit is still open...you might go back and enter some tag lines. Down the road it could help others when doing a search for fixtures/jigs of this type. Thanks in advance...If you have questions on adding Tag lines, Lew will answer them

8 hours ago, Grandpadave52 said:

you might go back and enter some tag lines.

THANKS Mike...Great job...

Help yourself

Thanks Mike for the plan,

Cal

Guys, I'm wondering if you have made any changes/improvements to this jig?

I was thinking of adding some way to hold it without clamping it??

Edited July 5, 20187 yr by Pat Meeuwissen

7 minutes ago, Pat Meeuwissen said:

I was thinking of adding some way to hold it without clamping it??

I'm interested now...

Stick I was LOOKING for a way to do it. Don't have one myself.

a pair of straight edge guides or a holding system like they have???

Affix one of these to the fixed side and or both sides beside the guide board.

 

that's what I said...

connect two of them together w/ a locking slide bar...

use a top bearing mortising bit for simplicity..

skip the guide board...

How about the idea of adding threaded rods through the width of the outer guide? Add t-nuts or threaded inserts  to provide the threads in the guide. This would fix the jig to the part being dadoed without needing clamps - a quick and easy modification to an existing jig too.