Exact Width Dado Jig

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Project by Chris McDowell posted 05-04-2013 09:37 PM 11675 views 15 times favorited 13 comments Add to Favorites Watch

This project was made the same way the wood whisperer made his; it’s just a little different. It took a few weeks to finish as I worked on it after work when I could and I went slow to make sure I wouldn’t mess up.

I had 3 of these old, black bookcase shelf-type things:

They are made of MDF and is the only wood I had on hand that I could make this out of, so I cut the top and bottom off of the biggest one.

I cut all the pieces I need out to size. I also had one leftover piece of S4S poplar that I got from the home store last year that I used for the edges.

I glued the edges to the fences.

Then I used a flush trim bit to trim the edges flush. I had to set the fences side by side so that the router would have enough surface to rest on. I used my very high-quality makeshift vise consisting of two pieces of scrap wood and some clamps to hold the work-pieces up.

I then had to make some slots for the adjustable fence. I don’t have a router table, so I used the drill press and drilled many holes.

I used carriage bolts and wing nuts for securing the adjustable fence. I would have liked to use a perfectly sized forstner bit for the task, but alas, the only size forstner bit I have is 2.5” for another project. The biggest drill bit I have is 1/2” which was still too small, so I just drilled around the hole until the carriage bolt heads were low enough. Messy, but it works.

I then attached the stationary fence. I put some glue and used my finishing nailer to secure it square. Once the glue dried I put 4 screws. I used my extremely accurate $11 Swanson brand combo square from Lowes to make the fence square. The other stupendously accurate carpenter’s square (of the same brand) was too big and difficult to manage, so I stuck with the 12 inch combo.

I realized I didn’t have a proper bit to do the dado’s with. The wood whisperer uses a top bearing bit and a guide bushing. I looked around and tried to find that exact setup, but it cost too much and I couldn’t find exactly what I needed to fit the router I have. My dad gave me a plunge router that takes a 1/2” shank, but it’s missing a plate on the bottom that the guide bushings would attach to. It is a no name brand router and I think I will have to take it to a woodworking store to figure out what I need. I went the easier, cheaper way and just ordered a 1/4” depth pattern bit with a 1/4” shank that I’ll used with the other router. It’s called a “dado & mortising” bit specifically. It’s by Amana.

So, now it was time to test it out. I put the work-piece under the jig and used the piece that was the width I needed the dado. I tightened it all up, and went to work.

I was so glad the bit actually worked OK. The dado is a tad bit loose because the edges made of poplar are not perfectly straight. If I had a hand plane I would plane them down like the wood whisperer to get them perfect. But, it worked out better than I expected and I am super happy with it.

It’s not as big as Marc’s, but that’s because I made this specifically for another project I plan on batching out. That project is small in size so I didn’t want some huge jig for it.

I had a lot of fun making this. I’ve been woodworking for almost a year and I still feel like a one-eyed monkey when I am trying to make something, fumbling around all over with dangerous tools (I am very safety conscious, though, and wear all of the proper PPE). I have no idea what I’m doing, but when something like this comes together and it actually works, it is very satisfying and fulfilling. I feel more confident with each project.

Thanks for looking.

Update 4-5-13
I had said that I used a pattern bit to trim the edges flush, but it was a flush trim bit, with the bearing on the bottom. I keep getting confused with the names. I didn’t have any pattern bits which is why I had to order the one I did. I corrected the text in this post to avoid confusion.

-- Chris, , FACEBOOK: , Proverbs 16:9

13 comments so far

View DIYaholic's profile


19921 posts in 3476 days

#1 posted 05-04-2013 09:45 PM

Well done. Should be a great shop aide.

One of these are on my very looooong list of shop projects!!!
One of these daze….

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View a1Jim's profile


118079 posts in 4378 days

#2 posted 05-04-2013 10:44 PM

View AngieO's profile


1267 posts in 2948 days

#3 posted 05-04-2013 11:35 PM

Looks great. I know what you mean about feeling like a one eyes monkey and then feeling great when something comes together. I always enjoy reading your posts and checking out your projects.

View eddie's profile


8565 posts in 3415 days

#4 posted 05-05-2013 12:48 AM

great jig ‘

-- Jesus Is Alright with me

View Jim Jakosh's profile

Jim Jakosh

24924 posts in 3906 days

#5 posted 05-05-2013 02:02 AM

Very neat and handy jig!Thanks for sharing the process, too!!!!!!!!!!...............Jim

ps, to make that relief, you can draw a circle and free hand hitting it with a router bit and it will be nice and flat on the bottom.

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View dnick's profile


986 posts in 3183 days

#6 posted 05-05-2013 03:40 AM

I like it. Nice job.

-- dnick, North Hollywood, Ca.

View Chris McDowell's profile

Chris McDowell

645 posts in 2953 days

#7 posted 05-05-2013 11:11 AM

Thanks for the comments everyone.

Jim Jakosh: thanks for the tip. I never thought about doing that.

-- Chris, , FACEBOOK: , Proverbs 16:9

View sgmdwk's profile


308 posts in 2673 days

#8 posted 05-05-2013 03:08 PM

The little triumphs from figuring out how to complete a task without the ideal tools are always sources of great satisfaction. From all of us who “make do,” Well done.

-- Dave K.

View OleTimer's profile


4 posts in 2670 days

#9 posted 05-05-2013 04:23 PM

Great job with limited resources – and an equally good job documenting so that the rest of us could benefit from your ingenuity!! Thanks for taking the trouble to give us the details.

View Bluepine38's profile


3387 posts in 3886 days

#10 posted 05-05-2013 05:01 PM

Great little jig, I missed Marc’s, so this is the first time I have seen this. With your tips and a little work, I think
that I will make one for my shop. Thank you for sharing.

-- As ever, Gus-the 80 yr young apprentice carpenter

View Chris McDowell's profile

Chris McDowell

645 posts in 2953 days

#11 posted 05-05-2013 08:29 PM

Thanks Dave, OleTimer, and Bluepine for the encouraging comments. I truly appreciate them.

-- Chris, , FACEBOOK: , Proverbs 16:9

View Greg D's profile

Greg D

238 posts in 2752 days

#12 posted 05-05-2013 09:03 PM

Nice job. I made the same one as well with my own modifications. Its nice to know the dado will be a perfect fit ever time.

-- Greg D, Cen. CA, "Keep it on the Level, Do it Right the First Time!"

View kiefer's profile


5730 posts in 3468 days

#13 posted 05-06-2013 04:09 AM

What you show in the pics is what I call a pattern bit ,no need for a bushing with it as the bearing follows the guide .
I use this type of bit a lot as is cuts on the line so no need to worry about the offset calculation that a bushing set up would need and it is always centred not like a bushing setup which relies on the base plate to be dead center to the router shaft .
I designed my door hinge template jig to work with this type of bit and it works great every time .

-- Kiefer

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