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How to Build a Strong Mortise and Tenon Bench

Updated on September 26, 2016

A Bench That Can Serve Many Functions

The joinery on this bench actually tightens when it is used.
The joinery on this bench actually tightens when it is used.

The Useful Bench

Benches have been around for some time and though all are useful, some yield more uses than others. The ideal bench is very strong; strong enough to stand on if you use it to reach something high. It is also used to sit on like it were a piece of furniture. It should also be nice looking if it is something that is kept in the home.

This mortise and tenon bench serves all of those functions. This is a simple bench that offers some challenges for the builder. These same challenges not only create an attractiveness to the bench, but also give it it's unique strength. The materials for it are easy to obtain and the outcome is stunning!

Although I have designed this bench and have never seen another one quite like it, I am hesitant to take credit for it. It's lines are very simple and there are just too many bench designs out there that haven't been seen by the masses.

Everyday Materials

When I built my first prototype for this project, I wanted to keep one thing in mind; simplicity. Simple and easy to find materials, a rather simple look, and simple finish.

The boards that I used are standard construction grade, 2 x 6 Pine lumber; the kind found at the local lumber yard. You could also use 2 x 12 Pine lumber and save yourself gluing up boards, but it's easier to find better lumber pieces without having to look too hard and it also reduces the cost of the lumber. You will need boards that are flat with no warping and no large knots.

The finish that I use produces an aged finish. The finish ingredients are brewed strong coffee, white vinegar, and a steel wool pad. If you want to take it further like I did you will add Linseed Oil and paste wax for the final enhancement. You could always opt for a painted finish or stain and varnish finish if you choose.

Let's get started!

common 2 x 6 Pine boards are used
common 2 x 6 Pine boards are used

Select Your Lumber

I start by selecting two boards for the seat. In the photo above, I found two ideal boards. There aren't any large knots and the boards are nice and straight with no warping.

This particular bench will be three feet long but you can alter the design to accommodate a longer or shorter bench as needed. I am ready to move on by putting a chamfer, (angle cut), around the top edges of both boards. The chamfer will remove 3/8" from the edge and will be at a forty five degree angle.

Setting up the table saw blade at 45 degrees to cut the chamfers.
Setting up the table saw blade at 45 degrees to cut the chamfers.

Cutting the Chamfers

With the table saw blade set at 45 degrees, adjust the rip fence so that only 3/8 of an inch is taken off of the edges. This not only cleans up the edges, but also takes the "construction grade lumber" look away and replaces it with a cottage furniture look.

Assembling the Seat

In the progressive photos above, you can see how the chamfers are done and the look that you get with the two boards together. With the two boards exactly the same length, you are ready to glue them together. Once the glue is dry, you are ready to move on to the next step; marking the area for the mortise. You can see where I have done this on the boards above.

Locating the Mortises

The location of the mortise will be 4 1/2" from the end of the seat planks. Because this is made of construction grade lumber, this distance ensures that there is strength and good wood between the mortise and the end of the boards. There will be a 3" space between the mortises and the mortise itself will be 2" wide by 1 1/2".

Unlike other benches that are assembled with mortise and tenon joinery, these mortises will be cut at a 10 degree angle. The angle will go from your layout on the seat and angle toward the edge of the board as you cut through the boards. This will be repeated at the other end of the seat.

Cutting the Mortises

When starting to remove wood from the mortises, you will want to have a bevel guage set at 10 degrees to check you progress. Begin by drilling several holes in the area to be removed. This greatly speeds up the process.

If you want to cut your mortises in a traditional way, you will need a sharp chisel and a mallet. Taking your time and working carefully, gradually remove wood from the mortise. Occasionally check the angle to be sure that you are maintaining the 10 degree angle.

If you own a scroll saw or a saber saw and want to speed the process, most of the wood can be removed with these tools. The seat boards are a little cumbersome to hold and handle, but it can be done. If using this method, clean out the mortise with a chisel after sawing.

Drill holes in the area to be removed. This makes forming the mortise much easier and quicker.
Drill holes in the area to be removed. This makes forming the mortise much easier and quicker.
Final cleaning of the mortise.  Make sure that the sides are straight so that the tenon can slide through easily.
Final cleaning of the mortise. Make sure that the sides are straight so that the tenon can slide through easily.
Checking the angle to make sure that you have a 10 degree angle.
Checking the angle to make sure that you have a 10 degree angle.

Making the Legs

If you are using 2 x 6 lumber like I do, you will need to cut two boards 21" long and glue side by side. You will need another set for the other end of the bench. With the boards glued together, you will set the blade of your table saw at 10 degrees. Cross cut the top and the bottom ends with a 10 degree angle.

With this done you are now ready to taper the sides of the legs. The base will be the full 12" width and then taper to 9" at the top. Begin by marking the cut lines on the boards with a pencil. Depending on what tools you have at your disposal, you could make these cuts with a handsaw, saber saw, or a table saw.

I made a simple jig that I can use with my table saw that holds the board at the angle that I need to make the cuts.

Angling the Sides of the Legs

The legs will start at the widest point at the base where the legs are located. The actual width here will be 11 1/2". The legs will taper toward the top where they will be 9" wide at a point 19" from the base.

To cut this angle, I made a very simple taper jig to use on a table saw. As you see in the photo, this is a piece of 2 x 2 lumber that is about 25" long. Next I fastened a piece to make an "L" shape. Finally drilled a hole to accommodate a 3"carriage bolt in the 25" piece, inserted a nut into the top of the hole, and can screw the carriage bolt in and out to create the angle that is desired.

To prepare the legs for tapering I marked the cut line on the board. Next, I put a straight edge along the saw blade and adjusted the angle on the jig until it matched the needed angle.

One thing that is great about this type of project is that it is forgiving; that is, if the cut isn't exactly on the line it's still alright. This is a rather rustic piece and our forefathers used what tool that they had to construct their benches.

Using the shop made jig, I am able to safely cut my tapers and stay right on my marked lines.
Using the shop made jig, I am able to safely cut my tapers and stay right on my marked lines.
With both tapers cut, you should have legs that look like this.
With both tapers cut, you should have legs that look like this.

Finishing up on the legs

After you have your boards tapered, it is time to cut the arc that form the feet on the bottom of the legs and cut the angled mortise for the cross member.

For the arc, set a compass for 6" diameter and scribe a line. The top of the arc will be 3" from the bottom edge of the board and will leave 3" on either sides for the legs. (see drawing)

For the angled mortise, the bottom of the mortise will be another 3" from the top of the arc. The mortise will be centered on the board and will be 1 3/4" high and 3/4" wide. Make sure that you angle the mortise in the correct direction. On the outside of the leg, the mortise will angle 10 degrees upward to accommodate the cross member.

Cutting the 6" diameter arc with a scroll saw.
Cutting the 6" diameter arc with a scroll saw.
The finished tenon for the crossmember.
The finished tenon for the crossmember.

Finishing up with the top tenons

To finish up our legs, we now have to cut the tenons that will fit through the seat. The tenons will be 2" wide with a 3" gap in between. The tenons will be 1 1/2" in height so that when they fit through the mortises on the seat, they will be flush with the top.

Cutting the tenons on a scroll saw.  To insure a good fit with the joinery, it is a good idea to make the tenons just slightly larger than needed and then shave off the excess wood for a great fit.
Cutting the tenons on a scroll saw. To insure a good fit with the joinery, it is a good idea to make the tenons just slightly larger than needed and then shave off the excess wood for a great fit.
The finished leg section
The finished leg section
Line drawings of the legs and seat, showing the angled mortises.
Line drawings of the legs and seat, showing the angled mortises.

Making the cross member

You are now ready to mill the last major piece of the bench; the cross member. Start by cutting a board three feet long. The piece should be 1 1/2" thick and 2 1/4" wide.

Next we will cut the tenons that will fit into the mortises in the legs. Measuring 3 3/4" from the end of the board, make a mark and then draw a line at a 10 degree angle that angles out toward the end. (see drawing) With a dado blade installed on your table saw, set the height of the blade on the table saw at 3/8" high and then set the miter guage on the saw at 10 degrees. Lining the blade on your mark, start removing wood and continue making passes until you reach the end of the board. Repeat on other end of board. This can also be done without a dado blade but will take a little longer to remove the wood.

Remove the dado blade and put regular crosscut blade back on the table saw. Set blade height at 3/8 ". Set the angle of the blade at 10 degrees and set the miter guage at 90 degrees. Start making passes on the top and bottom of the tenon to get the needed height to fit the mortise. Repeat on opposite end.

Smooth the saw marks on the tenons and fit through leg mortises. I also like to round the ends of the exposed tenons that will protrude on the outside of the legs.

Cutting the pins and the mortises

You are almost done at this point. With the cross member in place in the legs and the legs attached to the seat, You will need to mark the area to cut mortises for the pins. The mortises need to be right next to the legs and should be 5/8" high and 1/2" wide.

With the mortises cut, you will finish by cutting the pins that fit into the mortises. The pins will be 4" long and 5/8" wide and cut from 3/4" stock. Sand the stock, keeping it 3/4 on one end and tapering it down to 1/4".

The pins that will go into the mortise
The pins that will go into the mortise
The completed joint
The completed joint

Getting ready for a finish

This bench will hold itself together without any glue or fasteners, however, you can glue the leg tenons into the seat mortises if you choose. With everything assembled, plane or belt sand the top of the seat so that everything is flush and smooth on top. Sand all pieces until the saw marks are removed.

Construction is complete and you are ready to put a finish on your bench if desired.

Selecting a finish

As with any wood piece, you have some choices to make as far as a suitable finish. After your had work of making mortise and tenon joinery, you need to show it off. A quick and easy finish would be to stain and varnish your bench. When I build these benches, I want them to have a finish that makes them look very old and I use an ageing process on the wood to achieve this.

I begin by brewing about 4 cups of very strong coffee. I paint the coffee on the entire bench. You don't want to miss any area. Make sure every square inch gets covered. After this, I take a cup of white vinegar and put it into a glass jar. I then put a steel wool pad into the vinegar and allow to sit over night.

The following day, paint the vinegar solution on every square inch of the bench. After about 30 minutes you will see the vinegar reacting with the tannic acid in the coffee and creating an aged look before your eyes. This will produce a gray, weathered look to the wood. You could just stay with this look but I will take this a couple of steps further.

After the aging process, I will brush on a coat of Linseed oil and allow to dry over night. The following day I will rub on a coat of paste wax. This will produce a very warm but aged look to your bench. The wood will continue to grow a little darker and richer over the next month and creates a finish that you just can't obtain any other way.

The completed bench

This bench is now completed! The finish will make this piece of furniture look nice in any room in the home. This design where the legs are angled inward at the top will actually tighten up when the bench is in use. The mortise and tenon joinery is a challenge but the work pays off in a big way!

I have made many of these benches and will make many more in the future. I hope that this will be an enjoyable project for you. Enjoy!

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    • Phyllis Doyle profile image

      Phyllis Doyle Burns 17 months ago from High desert of Nevada.

      Hi Michael. It is good to see you again. This bench is beautiful. I love the finished aged look and the way you achieved it is remarkable. My Dad was a wood-worker and made toys, child chairs, rocking horses and garden furniture, so I really enjoy reading your articles - it brings back memories and I so admire your work.

      This is a very well-written article with detailed step by step instructions. Well done, Michael. Sharing and pinning.

    • emge profile image

      Madan 17 months ago from Abu Dhabi

      I love carpentry. Learned it in school. Very nice hub with a lot of practical info

    • ChitrangadaSharan profile image

      Chitrangada Sharan 17 months ago from New Delhi, India

      Excellent hub with all the details to build an elegant and attractive looking bench. As usual your work is very neat and well explained.

      I was just wondering whether you have left HP! So good to see another wonderful hub from you.

      Thank you for sharing!

    • MHiggins profile image
      Author

      Michael Higgins 17 months ago from Michigan

      Thanks Phyllis for the kind words! This project was initially planned to be published in a woodworking magazine. The publisher felt that they had something featured earlier that was too similar. Thanks for stopping by!

    • MHiggins profile image
      Author

      Michael Higgins 17 months ago from Michigan

      Thanks ChitrangadaSharan for stopping by! I have been spending most of my time designing projects for woodworking magazines and am also working on a project book to be published in the near future. I plan to get more articles done on this site now that things have slowed down some. Thanks for the kind words!

    • MHiggins profile image
      Author

      Michael Higgins 17 months ago from Michigan

      Thanks emge for reading my hub! I glad that you enjoyed it. If you ever try to build one of these, I would certainly encourage you! Thanks again!

    • profile image

      tupou 3 months ago

      Very interesting to see... thanks for that

    • MHiggins profile image
      Author

      Michael Higgins 3 months ago from Michigan

      I'm glad you enjoyed the hub! Thanks for taking time for the comment as well!

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