Adjustable Router Dado Jig for Perfect Dados and Grooves

A router dado jig is one of the most needed jigs for a trim router. The versatility of the tool is fantastic. Not only can you cut dados or rabbets but also cut mortises, and make t-joints or t-tracks. It is a great help in the workshop. Build an adjustable router dado jig with this step-by-step tutorial and video.

A router dado jig is a perfect tool for cutting dados, rabbets, and grooves. It is a huge helper when it comes to making t-joints or when cutting t-slots in wood. But its use is wide and can be used as a mortising jig as well. The jig offers many options and its versatility is what makes it a must-have for woodworking.

I have already built a similar dado jig for a router and I have used it for countless projects. It is easy to set up and really simple to cut a dado with. It has been one of the most used jigs in the workshop and it is definitely one of the top 3 jigs for a router.

Over time, I realized the jig needed something more – an adjustable stopper. So, I went ahead and added that to this updated Dado jig.

An adjustable stopper makes it easy to cut exact-width dados, rabbets, or mortises. Also, the stopper acts as a parallel guide so cutting squares or rectangles is an easy job.

An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a dado jig for router.
Router dado jig t-tracks

Although cutting squares or mortises with this jig is simple, I use it most for cutting slots and making t-tracks. Once the dado jig is set up you can easily make repeated cuts.

I built this upgraded router jig over a weekend. The material is easily available, the only thing you really need is an MDF and a plywood desk, possibly aluminum slats.

This is quite an easy project for any beginning woodworker and one of the most useful jigs for a router. The tool offers many options, so you may be surprised.

DIY Adjustable Router Dado Jig Video

If you want to build a dado jig with stoppers for a trim router and want to see how it is done, watch the video below for a detailed step-by-step guide.

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Table of Contents

  1. The Material you will need
  2. General Questions
    1. What router bit should I use to cut dados?
  3. How to make a Router Dado Jig for Perfect Dados and Grooves
    1. Step 1: Build the Front Baseplate
    2. Step 2: Make a T-track
    3. Step 3: Build the Back Baseplate
    4. Step 4: Make T-track Bolts
    5. Step 5: Make Adjustable Stoppers
  4. Multiple Ways How to Use an Adjustable Router Dado Jig
    1. Using both parts of the dado jig together
    2. Using one part of the dado jig

*Safety is your responsibility. Make sure you know what you’re doing and take all necessary safety precautions while working with power tools. Safety comes first!

Always be cautious and careful when using any power tool.

What you'll need to make an Adjustable Router Dado Jig

Router jig base
MDF – 2x – 500 mm x 110 mm x 5 mm
Aluminum L angles – 2x – 500 mm x 12 mm x 14 mm

Router jig t-tracks
Plywood Strips – 2x – 50 mm x 20 mm x 6,5 mm; 2x – 500 mm x 15 mm x 6,5 mm
MDF Strips – 4x – 500 mm x 24 mm x 4 mm; 2x – 500 mm x 19 mm x 4 mm

Router Jig stoppers
Plywood – 2x -110 mm x 20 mm x 90 mm
MDF – 2x 260 mm x 20 mm x 4 mm

Tools:
Circular Saw – https://amzn.to/4aMD0xg
Trim Router – https://amzn.to/3HbQcOg
Proxxon Mini Table Saw
Bosch Cord Drill – https://amzn.to/3NSA3Bo (GSB 13RE Review)
Narex Chisels – https://amzn.to/3tHNJrT
One Hand Clamps – https://amzn.to/48jGxkZ
Spring Clamps – https://amzn.to/41Nuh9D
F-Clamps – https://amzn.to/48ArzY1
Machinist Square / Speed Square

Other:
Double-Sided Woodworking Tape – https://amzn.to/3tPMGpM
Wood Glue – https://amzn.to/48ltKhJ
Epoxy – https://amzn.to/3tJ5R4L
Router bits – 6mm – https://amzn.to/3NQNDVX
M6 Wing nut, M6 Bolts

Check all the Tools I Use

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What router bit should I use to cut dados?

The two best router bits for cutting dados, grooves, and rabbets are a double flute straight router bit and an upcut/downcut spiral bit.

  • Straight router bit cuts the material along its entire length, so more pressure is exerted on the bit blade. When using a straight bit, it is better to make shallow cuts with more passes. Thus, the resulting cut will be cleaner and there is less chance the router bit will get burnt or break.
  • Spiral router bit cuts the material only when the blade touches the stock. There is less contact between the router bit and the material, which is gentler on the blade. Unlike the straight bit that chops the material, the spiral router bit peels the material off leading to a cleaner cut.

Let's start building!

The Dado jig has 2 main parts – the base and the guide rail with t-tracks.

  • For the base, I am using a thin MDF desk. The thinner the base, the greater the depth of the cut. However, the desk needs to be strong enough to support the weight of the trim router.
  • The guide rails are made of aluminum L angles glued with epoxy to the base and are followed by t-tracks.

The overall dimensions of the dado jig are 500 mm x 22 mm, which gives roughly 30 mm to cut dados and grooves. One of the major benefits is that both parts of the jig can be used together or independently.

NOTE: The route dado jig is built and can be used with one router bit size only. If you use a 6mm router bit to build the jig then it can be used only with a 6mm router bit.

Also, take into account the type of your router and the router base. The distance between the front of the router base and the router bit might be different than the distance between the back of the base and the router bit – that would determine the width of the dado jig base plates and precisely defines which base plate is the front and which is the back.

How to make a Router Dado Jig for Perfect Dados and Grooves

Step 1: Build the Front Baseplate

First, measure and cut the MDF baseboard (final dimensions after cutoffs – 240 mm x 60 mm x 12 mm). Cut the baseboard slightly wider, though. The wood excess will be cut off later.

To cut both the baseboards I was using a circular saw with a circular saw straight edge guide and circular saw track, though a table saw would work just as well.

Building a router groove cutter for precise dados, grooves and rabbets. How to make a router dado jig.

Mark the position of the aluminum L angle (50 mm from the bottom of the MDF strip). Cut a shallow dado to make the angle flush with the surface. Apply epoxy and glue the angle to the baseboard.

An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.
Straight edge jig for a router to cut long straight dados and grooves.

NOTE: Since the MDF baseboard is too thin, I am using epoxy to glue the aluminum angle to the MDF. Screws would not work here. As a benefit, the installed angle will reinforce the baseplate.

Step 2: Make a T-track

Cut all the wood strips necessary for the t-tracks. Start gluing the individual wood layers on top of each other and make a t-track. The first layer is the MDF baseboard, then the plywood strips 6,5 mm, and then the MDF strips 4 mm.

Make sure the glue does not get in the track, otherwise, it is quite complicated to clean it.

TIP: You can use t-track bolts or thin strips of wood as separators when measuring the distance between the t-track layers (Step 4).

How to make a homemade DIY t-track. Router jig.
How to make a dado jig. Router dado jig
Making t-tracks from wood strips

Once the glue dries, cut off the MFD excess from the base using a router. The router bit size you will use for that will determine the size of the bit you will need to use together with this router jig. If necessary, make a mark on the baseboard to know that this is the front piece of the jig and needs to be used together with the front part of the router base.

An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.
Cutting wood excess from the base board

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Step 3: Build the Back Baseplate

Repeat Step 1 and Step 2 to make the back baseplate of the router jig. When cutting the wood excess turn your router and use the back side of the router to make the cut.

Now you have the front and the back baseboards.

An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.
Aligning the front and back baseboard of a router dado jig. How to cut a dado with a dado router jig.

Step 4: Make T-track Bolts

Cut 4 plywood pieces for the t-track bolts (30 mm x 15 mm x 6,5cm) and round the edges. Drill a 6mm hole in the center of the piece and carve a hexagon around the hole to fit in the bolt’s head and make it flush with the surface. Use epoxy to fix it permanently in place.

Making a t-track bolt for a router dado jig.
Making DIY t-track bolt for a router jig. How to make a router dado jig.
An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a dado jig for router.

NOTE: You can grind the bolt’s head to make the entire t-track bolt thinner. The carved hexagon doesn’t have to be that deep.

Step 5: Make Adjustable Stoppers

Cut the wooden strips for the stoppers (Plywood, MDF). Route slots at the ends of the MDF strips for adjustments and glue the strips with the Plywood pieces.

When gluing the plywood pieces, note, that they should fit between the baseboards entirely when the router dado jig is in its minimum position.

A router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.
An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.

Improvement to the stoppers

Add perpendicular wooden strips to the stoppers. This is especially useful when cutting a precise shape such as a square or rectangle and you want to follow a drawn shape.

  • Use harder material like plywood. ( I used MDF but after some time the edges became worn)
  • The width of the strips is at most equal to the bit thickness (in my case a little less than 6mm). Make the strips longer, they will be cut to size during the first use of the jig.
  • When installing the stoppers on the t-tracks, make sure the perpendicular strips are right between the baseboards.
  • Use epoxy to glue the strips to the stoppers. Additionally, you can use screws but make sure they are flush with the surface)
An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.
Router dado jig stoppers for exact width cuts

Below is a picture of a finished Dado jig for a router with added stoppers. I love this jig. There are so many things that can be done with this router jig. I have been using it for multiple projects and it is for sure one of the most practical and useful jigs for a trim router.

An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a dado jig for router.
Finished router jig for cutting dados and grooves

Multiple Ways How to Use an Adjustable Router Dado Jig

There are a few ways to use an adjustable router dado jig. The versatility of the tool is great. It has a wide range of uses which are described more in detail below.

All methods require that the jig be attached to the material being cut, or to the table. The base and the stoppers are not firmly fixed to each other so all parts can be used independently.

1. Cut Dados and Grooves

The router jig can be used to cut precise exact-width dados and grooves.

Insert a reference piece in the dado jig, adjust both the base plates and the stoppers around the piece, and lock the jig down. Remove the material from the jig, insert the router, and make a cut. Thus, you will get an exact width dado. This method is suitable for making t-joints.

Cut dados, grooves and rabbets with a dado jig for router.
Cutting precise dadoes with a router

2. Cut Precise Squares and Rectangles

Draw the square on the workpiece. Place the router jig on the workpiece and align the baseplate edges and the stoppers with the drawn lines. Cut the square and use a chisel to clean the corners.

An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a router dado jig.
The adjustable dado jig can cut exact shapes such as squares or rectangles

3. Cut T-Tracks

Place the dado jig on a workpiece with the drawn lines. Align the inner edges of the jig with the lines and lock the jig down. Then, make the cut. This is my preferred method of creating t-tracks.

How to make t-tracks with a router dado jig. DIY router dado jig.
Making T-tracks with a router dado jig

4. Cut Mortises

Set the length and the width of the tenon on the dado jig and lock it down. Place it on a drawn/marked mortise and make a cut.

5. Cut Rabbets

The dado jig can be used separately since the two base plates are not firmly fixed to each other.

To cut rabbets, place the jig on the edge of a workpiece. Align the inner edge of the base plate with the drawn line, clamp the jig down, and make a cut.

6. Make Straight Long Cuts

The aluminum rail on the base plate can also serve as a guide for making straight long cuts. Place the base on the workpiece, clamp it down, and make a cut.

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An adjustable router dado jig is the perfect tool to cut dados, grooves or rabbets. How to make a dado jig for router. Dado Jig for Router.

I hope the information shared in this blog post inspired and now you are adding this router jig to your next builds. 😉

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About the author, Lukas
About the author, Lukas

Meet the creator of AllFlavor Workshop! As a passionate DIYer and woodworking enthusiast, Lukas is always looking for ways to make things himself rather than buying them off the shelf. With a keen eye for design and a knack for working with wood, Lukas enjoys sharing his craft with others and helping them discover the joy of building. Whether you're an experienced woodworker or a novice looking to try your hand at a new hobby, you're sure to find plenty of inspiration and tips on AllFlavor Workshop.