Who has the best router dado jig?

[keith ouellette]

I need to make dados across some 80" long plywood. I don't have a way of sliding in across the dado blade on the ts so I want to make a router jig so i thought I might look at some current examples if any one would like to share.

I searched it and found Glen bradleys jig but was wondering if there are other ways as i don't have a router with a collar set.

[glenn bradley]

The original version of that jig used the edge of the router base against the guide. I just used the bushing as it does not give me problems if I rotate the router or use a different "spot" on the base from one cut to the next.

I don't know that this type of jig would be good for an 80" long dado anyway. That's quite a stretch. I would consider just ripping a piece of MDF or something on the tablesaw to assure a straight edge and clamp it to the piece as a guide. Commercial ones are available out of aluminum and such but I have not found them any more convenient than a shop ripped one. I have a 97" x 5" strip in my lumber rack right now that I use for such things.

[Dave Cav]

Cut an 80 inch (or longer) strip of plywood about a foot wide. Cut another strip just as long and a couple of inches wide. One edge needs to be straight. Measure your router base and screw the second strip on top of the first (wide) piece with the clean, straight edge of the second (narrow) strip 1/2 the router base's width from the edge of the first (wide) piece.

Put your dado bit in the router, and put the router on top of the wide strip with the edge of the base against the narrow strip, which is now your fence. Trim off the excess (and there needs to be a little excess to trim off) so the lower (wider) piece is straight and the egde is parallel to the upper fence piece.

To use, put the edge of the lower piece directly where you want to route your dado, clamp at both ends and use the fence to guide the cut. Note that this will only work properly with the same size bit you used to cut off the edge of the lower piece, so if you are going to make dados of different sizes you will need to make one jig for each size.

Let me know if this doesn't make sense and maybe I can post some pictures.

[keith ouellette]

no no no :D.

Across an 80" long piece of plywood not along its length. If the dado was 80" long then the ts would be the way to go.

The plywood is only 25" wide and I need to make 5 dados along its width. sorry I didn't make that clearer.

[johnny means]

Just clamp a square board flush with your front edge and rout away.

[Joe Scharle]

I've been asked about this jig so many times I have the source memorized...Shopnotes #76. They also have a video on the site. I have 3 of these: 1/4" bit, 3/8" bit and 1/2" bit (different routers), mainly because they were fun to build and use. Also use the 1/2" for sliding DTs.

http://www.ncwoodworker.net/pp/data/194/Dado_Jig.JPG

[Rick Moyer]

Joe, I'm curious about the elliptical opening. What is it for; is it necessary or an added benefit for something?

[Alex Berkovsky]

Joe, I'm curious about the elliptical opening. What is it for; is it necessary or an added benefit for something?Rick,
Here's how the magazine describes it: "Relief hole lets you set router in place without marring jig or workpiece".

http://www.shopnotes.com/issues/076/videos/using-the-shop-built-dado-jig

[Joe Scharle]

Alex is correct, but the opening also helps to quickly locate the next line while sliding the jig up to the next dado position.

[Wayne Jolly]

I have made one of the Shopnotes jigs and it works great. So I guess that means +1 from me.

Wayne

[Shawn Christ]

Here's a downloadable plan for a jig similar to the one above. Made it a few months ago and it works like a charm.

http://www.woodsmithshop.com/download/204/adjustabledadojig.pdf

You may need to sign up for their free weekly e-tips to get the plan (and others posted from the Woodsmith Shop TV show).

[Mark Buchanan]

Festool router and guide rail. AAAplus.

[Rob Fisher]

Does anybody know where I would be able to get a copy of Shopnotes 76? I would like to build the above mentioned router jig. :)

Thanks,
Rob

[Curt Harms]

Here's a downloadable plan for a jig similar to the one above. Made it a few months ago and it works like a charm.

http://www.woodsmithshop.com/download/204/adjustabledadojig.pdf

You may need to sign up for their free weekly e-tips to get the plan (and others posted from the Woodsmith Shop TV show).

We all know that plywood thicknesss varies. Instead of running the router baseplate between rails, I use a top bearing flush pattern bit 1/2" diameter 1/2" cutting depth. Make the jig rails 3/4" thick. Clamp one jaw of the jig along the desired edge of the dado. Put a scrap of the shelf material between the jaws and clamp the other jaw of the jig snug to the scrap of shelf material. Run the top bearing router bit along the walls of the jig jaws. Perfect fit every time! The only downside to this is I haven't found top bearing pattern bits smaller than 1/2" so that's the narrowest dado this jig will cut. If you make the first pass really shallow there will be very little or no tearout.

[Jerome Hanby]

I know this is an old thread, but thought I'd take a shot. Did you put the clamp on your jigs? i don't see it in your picture. I'm having problems making my clamp work and was looking fro some insight.


I've been asked about this jig so many times I have the source memorized...Shopnotes #76. They also have a video on the site. I have 3 of these: 1/4" bit, 3/8" bit and 1/2" bit (different routers), mainly because they were fun to build and use. Also use the 1/2" for sliding DTs.

http://www.ncwoodworker.net/pp/data/194/Dado_Jig.JPG

[Trent Shirley]

WoodSmith Shop had a very basic combination jig that I like the idea of. It is a length of wood to act as a guide and a wider length of hardboard below. They have one side set for a circular saw so that the blade rides at the edge of the hardboard to reduce tearout. The other side is sized for a router to make dado cuts.
I was thinking of making one long one and then cutting it in half, then fitting the two ends so they will mate into one another so you can use it shorter or longer at will.
I was also considering trying to combine the two sided dado jig style above with the straight edge guide for the circular saw so they would be in one jig and save me some storage space.

Right now I use a $20. set of aluminum guide rails that just clamp down to the work piece. The downfall is that you have to set your marks calculating the extra distance from the edge of the guide to the edge of your bit. The two piece wood and hardboard combo makes setup and cutting very easy.