How to Make a Timber Coffee Table, Using Mortise and Tenon Joinery

This build can be made from simple, store milled limber. In my case I used pine which is relatively inexpensive and easy to work with.

The main tool in this project is a router.

Step 1: Cut Timber Stock to Length

I purchased a 1.8 meter length of 42mm x 42mm pine from my local hardware store. If you change the size of the table there are a few different basic sizes of square stock to match it proportionately. In other words you don’t need to worry about milling anything unless you really want to.

I cut these pieces, which would be the legs, 400mm long. That’s a standard coffee table height. I then cut 4 rails using standard 42mm x 19mm pine stock. Be careful to work out your measurements when cutting the rails; you need to consider the width of the legs, then how long the rail needs to be, then add the extra length for the tenons.

Step 2: Cut Mortises

Once I had all the pieces for the base I started marking out the mortises. I started the mortise 10mm in and went 15mm deep. This meant there was enough wood to support the rail once all the material was cut away.

I used a plunge router with a 12mm straight cut bit. I made each cut in 2 passes. Using an edge guide and a stop block at the end of the cut I was able to make each mortise the same. Lining all the legs up together gave me a wider surface to rest the router on.

The router left rounded ends to the mortise so these needed to be squared up using a chisel. The other option would be to round the tenons but I thought this would be easier.

Make sure to mark each mortise, this will make sense in a second.

Step 3: Cut Tenons

When drawing the lines for the tenons, score the line with a knife. This will ensure that the fibres break in a uniform line. The tenon needs to be cut thinner than the stock so that if the rail shrinks you won't be able to see the gap.

I then switched to the trim router and set my depth to less than I thought was needed. I free hand cut the piece but didn’t get too close to the line, I would clean this up later with a chisel. If the fit was too tight I would drop the router bit a little bit at a time until the fit was snug. I cut both side of the rail to ensure that the tenon was centred.

Step 4: Test Fit and Make Adjustments

Now you can test fit a corner. Once you’re happy with the fit mark the rail the same as the leg. Each one will be slightly different so it’s better to cut and fit each one.

Step 5: Sand and Glue

I had a piece 650mm x 650mm x 25mm bench top left over from another project so all I had to do here was sand it up to 180 grit. I then sanded all the pieces and rounded all the edges. Make sure to round the edges of the bottom of the legs. This will help to make sure they don’t chop if the table is slid along the floor.

Then I glued the rails into the legs 2 at a time. you could the whole table at once but I don’t have enough clamps. Make sure to clean up all the glue squeeze out now before it dries. After gluing the whole frame together make sure to check for square and adjust the clamps if necessary.

Once all the glue has dried you can seal using paint or a clear coat.

Step 6: Attach Table Top to the Base

To attach the table top I used figure 8 metal clips. These allow the table top to expand and contract with the season, independently of the frame. To install these either route or chisel a shallow slot in the rails and attach 4 or more clips (I used 6).

Flip the table top over and place the frame in the centre. Pre drill and screw the top to the frame. Make sure the screws don’t come through the other side.