Curt Harms
08-01-2020, 10:04 AM
There was a thread about cutting dados with a router. I have a project in the works that requires dados so decided to take some pictures. Here's the jig I built. It's just MDF with wood liners. The router bit bearing runs against the 'jaws' and I don't know that MDF would wear well
438017438016
I just draw a line where I want one edge of the dado to be and align the fixed jaw of the jig with that line and clamp the fixed jaw
438026
I set one of the shelves against the fixed jaw and move the movable jaw tight against the shelf and tighten the thumbscrews. They should be knobs, knobs would be easier to tighten.
438027
I used a Grizzly trim router with 1/2" X 1/2" pattern bit. The cutting length of the bit has to be short enough that the bearing will ride against the jig not above it.438030438031
One pass up the left side and down the right side. Done.
438033
It's taken longer to describe it than to do it. I like the router jig method for two reasons. One is that the dado bottom and sides are very clean. Clean accurate cuts should result in good strong glue joints. The second reason is easy size adjustment. We all know that plywood can be variable in its thickness. A jig like this makes it easy to adjust the dado to the plywood thickness. The biggest shortcoming I can think of is that it will only cut dados 1/2" wide or wider. There is a similar setup that uses collars and straight bits rather than bearing guided bits. That configuration will cut dados as narrow as the available straight bit. Thanks for looking.
438017438016
I just draw a line where I want one edge of the dado to be and align the fixed jaw of the jig with that line and clamp the fixed jaw
438026
I set one of the shelves against the fixed jaw and move the movable jaw tight against the shelf and tighten the thumbscrews. They should be knobs, knobs would be easier to tighten.
438027
I used a Grizzly trim router with 1/2" X 1/2" pattern bit. The cutting length of the bit has to be short enough that the bearing will ride against the jig not above it.438030438031
One pass up the left side and down the right side. Done.
438033
It's taken longer to describe it than to do it. I like the router jig method for two reasons. One is that the dado bottom and sides are very clean. Clean accurate cuts should result in good strong glue joints. The second reason is easy size adjustment. We all know that plywood can be variable in its thickness. A jig like this makes it easy to adjust the dado to the plywood thickness. The biggest shortcoming I can think of is that it will only cut dados 1/2" wide or wider. There is a similar setup that uses collars and straight bits rather than bearing guided bits. That configuration will cut dados as narrow as the available straight bit. Thanks for looking.