Auto Adjust Router Dado Jig - 1

glenn bradley

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Don made the mistake of asking for more jig posts so here's the next with more to follow. The concept of the jig has different versions. For any version you want some flat stable lumber. I had an old maple table top that was part of my parents newlywed furniture 50-odd years ago. It had picked up some water damage while making it's travels from one of my dad's garages to the other over the years. I ended up with it and it has been waiting for a second life.

The jig requires two guide rails to control the width of the cut and two end rails to support the guide rails.

wood cuts.jpg

The general layout allows the guide rails to open and close for different widths of dados.

general layout.jpg

Over to the drill press to drill some starter holes for the adjustment slots.

starter holes.jpg

On the narrow guide rail I also need a hole for the carrige bolt and a recess for the head of the bolt.

recess holes.jpg

As my router table was down I used the old standby to cut the slots.

slots.jpg

Cont'd in Part 2
 
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Auto Adjust Router Dado Jig - Part 2

To allow the router bit collar to ride along the guide I cut some rabbets. I make the cut deep enough so that in a later step the collar will ride in the rabbet and the bit will cut the extending shelf of the rabbet to size.

coller.jpg

Here's a shot of trimming the rabbet 'shelf' to create a sort of zero clearance reference edge on the guides. I now know using this guide and bit, the cut will be right on that edge.

coller and bit.jpg

With that done I can attach the side rails permanently to the wide guide rail.

attach rails.jpg

With the side rails attached I add the carriage bolts, fender washers and some knobs for the narrow guide rail which moves to set the dado width.

knobs and washers.jpg

Now using the slots in the side rails and the carriage bolts and knobs, I can size the dado width using the actual material that will occupy the dado.

set jig width.jpg
jig to material.jpg

Then I make the cut.

cut dado.jpg

Now even if my material ends up being an odd thickness I can still make a nice tight dado.

perfect fit.jpg
 
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The Bandit Strikes Again!

Now THAT'S my kind of post! :thumb:
Thank you Glenn. :clap:
I have seen this jig but never in such an easy to make manor.
This way each step has a reason and a picture. This wil make a nice PDF file.

Keep-em-Commin' Glenn this is wonderful!

DT
 
Thanks Don. I forgot to mention that I have used the "rabbet shelf" along the edge of longer boards for a more accurate edge trimming guide with the same router, collet and bit set up. I just used this method to trim some large panels for a workbench I have in progress as I don't have a Festool or EZ smart rig.

Thanks again!
 
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