In this blog, I’ll show you how to build a jig that allows you to quickly and easily make accurate tenons.

When designing this tenon jig, my priority was that this jig should make it possible to make both cuts of the tenon with only 1 setting.
The cuts had to be repeated in quick succession and most importantly, the cuts had to be accurate so that a perfect connection can be made every time.

Curious about the result and the possibilities of this woodworking jig?

Here we go!

This is the first part of the construction of this jig as well as part 1 of the free plans.

The rest of the build and the second part of the free plans can be found by clicking the button below.

What does tenon mean?

I’ll start by explaining briefly.

A tenon is a piece of wood with a protruding part, sometimes called a peg.
This piece will fit perfectly into a mortise, made in another piece of wood.

In this way, you can firmly connect two pieces of wood.

What can a mortise and tenon joint be used for?

This is why the mortise and tenon joint is so popular: You can use the mortise and tenon connection for just about anything.

It is extremely often used in furniture manufacturing, as well as in the construction of wooden frames for buildings.

It is not only one of the strongest connections, but also a very elegant way of connecting.

Watch the video on how to build this jig

Ok, now you know what a tenon is and where you can use it for I can show you how to build this jig.

But before we dive into the blog you can watch the video first.
In that video, I will show you how I build my tenon jig.

In the blog post underneath the video, I will describe step by step the actions you need to take to make this jig.

Also, I will list up the materials and tools you need for building this project.

How do you make a mortise and tenon jig?

Now that we have gone through the list of what we all need for this project, I will explain step by step how to make this jig.

Let’s go!

Step 1 | Preparation

The first step in making this jig is to cut all the necessary pieces.

The dimensions for this can be found on the free plans that you can download in this blog.

After cutting the pieces for this jig you can drill all the holes at the indicated points. 

Preferably use a drill press.
If you do not have this, use a regular drill, and try to make these holes as square as possible.

To cut the pieces accurately and safely I used my crosscut sled.

If you want to make this crosscut sled yourself, be sure to check out my blog, How to make the most complete crosscut sled | FREE PLANS.

In that blog I guide you step by step in making this crosscut sled.
Free plans are also available on that blog.

To allow the 2 bottom plates to slide over each other so that you can adjust the tenon jig, a bolt must be fitted in the bottom plate and a slot in the top plate.

The head of the bolt that is fitted in the bottom plate must be countersunk in the wood.

Do this by inserting the bolt into the hole and marking the head of the bolt.

Then you can make a recess with the hammer and chisel in which the head of the bolt fits perfectly.

The slot that has to be made in the top plate can be made with the router and a straight router bit.

To make the slot perfectly straight, I used my homemade router jig. This router jig is very easy and quick to make, and you are always assured of a straight cut.

A while ago, I made a video of how I made this jig. You can watch it here: Simple router bit for Makita 3709 (you can make this for any router).

Once you have finished the slot it should look like this:

Step 2 | Making the adjustable bottom plate

Ok, now that the parts for the bottom of this jig are ready you can assemble them.

You can attach the two small boards to the sides of the bottom plate where the bolt is incorporated. These serve to hold the complete jig together and guide the sliding part.

I attached the sides with wood glue and brad nails. If you don’t have brad nails, you can use screws or regular nails for this.

You can now attach a stop block at right angles to the sliding part, the part in which you made the slot.

I did this by gluing it first with CA glue because this way the block is quickly firmly fixed.

Then I placed 2 screws from the bottom.

When installing these screws, don’t forget to pre-drill and make a countersink hole.

Step 3 | Calibration blocks for accurate cuts

Now comes the most crucial part of this jig, the calibration blocks.
It must be made precisely or the tenon jig will not work properly.

For the first calibration block, you have to cut a slot again.

The way you do this is identical to how you did this with the slot of the bottom plate. The only difference here is that the slot must be made in the middle of this part.

To be able to easily use the router, I first drilled a hole at the beginning and the end of the slot with my drill press.

To prevent the small part from shifting while making the slot with the router, I made the part larger so that I could easily clamp it on the workbench.

Once the slot has been made, you can now trim it to the correct dimensions.

You now have to attach two thinner pieces of wood to this calibration block, I used 6 mm MDF for this.

The piece that is attached to the calibration block at the back will serve later to determine the first distance to the saw blade. I’ll describe how to use this jig later.

The second piece of MDF can be glued to the front on top of the calibration block. This will act as a guide and clamp for the center calibration block.

To glue these pieces of MDF on the block I used CA glue again.

A piece of T-track must be placed in the block on the other side of the jig.

Mark where the T-track should be by drawing a clear pencil line on both sides.

Set the table saw blade to a height that is just slightly higher than the T-track. That way the T-track will sit slightly recessed when placed in the wood.

By sliding the fence of the table saw each time after a cut, you can make a slot in the wood that perfectly matches the width of the T-track.

After placing the T-Track you can make the block that fits in it.
Make a hole in the block so you can place the bolt.

To prevent the block from turning, I attached a second bolt. For this, I used a hexagonal wood bolt.

You can clamp the block in the T-Track with a button.

Because I find it fun and challenging making as much as possible myself, I also made this button myself.

See how I did it in my blog How to make cheap wooden knobs quick and easy | FREE PLANS.
It’s very simple and in that blog, you can also download a free template so that you can make these buttons yourself.

By fastening this block through the T-track with screws on the sliding part of this jig, everything will now stay in place.

The block that can be set in this T-track will serve as a stop block later when we move the tenon jig from the start position to the end position. 

Now comes the hardest part of making this tenon jig, building the last calibration block.
But don’t let it put you off, I’ll help you by explaining how to do this step by step.

This block must have exactly the same length as the block with the slot, plus the thickness of your saw blade.

I have a very simple trick to add that exact thickness to the size of the calibration block with the slot.

All you need is the block with the slot plus a thickness plate with the same thickness of the saw blade.

You make that thickness plate as follows:

Start by clamping a piece of scrap wood onto the crosscut sled and cut off the end.

This makes the end of this clamped block flush with the side of your saw blade.

Now take another piece of scrap wood.

Push it against the clamped block, and saw off the end as well.
This way you are sure of a right-angled cut and a good basis for your thickness plate.

Now turn the last block 90 degrees so that it is straight against the fence. Now push this block well against the clamped block and make a notch.

Slide the block with the notch again up to the clamped block.

In this way, a piece of the wood will hang over the clamped block.

Raise the saw blade and now cut off the overhang.

This piece now has the exact thickness of your saw blade.

Now that you have a thickness plate with the same thickness on the saw blade, you can make the calibration block.

For this, you use the calibration block with the slot as a basis.

Start by sliding the calibration block with the slot against the saw blade.

Place the thickness plate at the back against the calibration block with the slot.

Now take the piece of wood for the middle calibration block and place it flush with the back of the thickness plate.

Now cut off the last calibration block.

The only thing you have to do now to complete this calibration block is to attach the part in MDF to it.

This calibration block will determine the distance of the second cut. 

I’ll explain how it works later.

Step 4 | Assembly of this tenon jig

To assemble the base of this jig, put all the pieces in place and secure them with the knobs for now.

Below you can see a picture of how it should look like.

The rest of the build

Because the video I made about building this jig would otherwise be too long and boring, I decided to split the construction of this jig into two parts.

So do you want to know how to build this jig and do you also want the rest of the construction plans?
Then be sure to come back next week to watch the sequel. 

In that blog, I will also discuss some other important facts about making tenons. Don’t miss that!