How To'sHow To's section icon

Dating back thousands of years the mortice and tenon joint is one of the oldest ways to join two pieces of wood, comprising a mortice hole and tenon tongue which fit exactly into one another. It’s a versatile joint that can be used in many different types of woodworking, from fine furniture to large oak framed buildings.

Tool menu

Tools needed for cutting mortice and tenons by hand:

For cutting tenons by machine:

Finished tenon

Step 1

Prepare material for both parts of the joint.

Marking Out

Step 2

Joint is set out according to ‘Rule of Thirds’, whereby the proportions of the joint are approximately divided into thirds, thus if the tenon rail is 20mm thick, the mortice chisel is approx one third, so 7mm (arrowed).

Rule of thirds

Step 3

Set the mortice gauge pins to the width of the chisel.

Pins set to width of chisel

Step 4

Make two dots (arrowed), check from each side to ensure tenon is central.

Making a pair of dots

Step 5

Mark depth of tenon, approx two thirds depth of the second piece of timber (arrowed). This is the shoulder line, which should be heavily knifed.

Marking depth of tenon

Step 6

Holding the wood in the vice, make parallel lines all round.

Marking parallel lines

 

Parallel lines on end grain

Step 7

Set marking gauge to 6mm, gauge line all the way round (arrowed).

Marking edge of tenon

Step 8

Set marking gauge to timber width – 6mm, mark width of tenon (arrowed).

Marking furthest edge of tenon

Step 9

Completed marking out of tenon on end grain.

Marking out completed on end grain

Step 10

Lay tenon piece on mortice material, mark position of mortice in pencil (arrowed).

Marking position of mortice in pencil

Step 11

Transfer lines across wood.

Marking mortice lines

Step 12

Set mortice gauge to mark position of mortice, don’t alter the distance between the pins. Pencil in the waste.

Setting the mortice gauge

Step 13

Mark the width of the mortice (arrowed) with a knife.

Marking the width of the mortice

Chopping The Mortice

Step 14

Clamp the mortice position over the strongest part of the bench (the leg).

Clamping the mortice timber

Step 15

Stand at the end of the bench when chopping to align the chisel vertically.

Chisel positioned vertically

Step 16

Chop out the waste, using the chisel as a lever to remove the chippings. Stop 2mm (arrowed) from the knife lines.

Mortice chopping

Step 17

Check for depth, which should be 3mm longer than the tenon.

Checking for depth

Step 18

Two final cuts, one at each end, on the knife line. Check for square.

Chopping the last 2 cuts

Cutting The Tenon

We have detailed two ways you can cut a tenon; it can be cut either by hand (A) or with a bandsaw (B). Cutting by hand demands more control and can be more difficult, particularly if you are just starting out.

Cutting By Hand (A)

Step 19A

Make two triangular cuts, one from each side.

Chopping the last 2 cuts

Step 20A

Complete the cut but sawing horizontally to the shoulder line.

Sawing to the shoulder line

Step 21A

Make two further cuts on the broad faces.

Two further cuts on broad faces

Step 22A

Position tenon piece on the bench hook.

Tenon material on bench hook

Step 23A

Saw off cheeks from tenon all round, leaving 0.5mm waste on the shoulder line (arrowed).

 

Sawing of tenon waste

Step 24A

Position a wide chisel on the knife line, sight for square and chop the shoulder line. Alternatively, use a shoulder plane.

Wide chisel to chop shoulder

Step 25A

Use block plane to chamfer end of tenon (arrowed).

Chamfer on end of tenon

Step 26A

Test to fit, joint should push together with moderate hand pressure only.

Completed joint

Cutting With a Bandsaw (B)

Step 19B

Check bandsaw blade and fence are square to the table.

Checking blade for squareness

 

Checking fence is square to table

Step 20B

Make four saw cuts on waste side to finish at shoulder line.

Four cuts to finish at shoulder line

Step 21B

Mitre fence and ‘stop’ to cut off waste tenon cheeks.

Sawing off tenon cheeks

Step 22B

Tenon cheek waste removed.

Finished tenon
  • AG

    In Step24A, I guess you mean ‘sight’ instead of ‘site’. Otherwise, thanks for the method.

    • Rob Stoakley

      Indeed, many thanks.

buying-guides-iconclockfirst-look-icongoogleplushow-tos-iconinsights-iconinstagrammeet-icontagwhats-on-icon