How to Make Joint & Tenon
Mortise and tenon joints are among the most basic of woodworking joints, yet can be some of the strongest and most elegant. Woodworkers began using mortise and tenon joints long before the advent of mechanical fasteners, yet they're still commonly used in fine furniture today.
A mortise and tenon is little more than a slot (called a mortise) cut into one piece of wood, with a pin (called a tenon) designed to fit perfectly within the slot. The joint may be secured by glue, pins or mere pressure from the other pieces of stock in the project. This joint works best where the grains of the two boards being joined will be perpendicular to one another.
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Things You'll Need
- Sharp bevel-edged chisel
- Hammer or mallet for striking chisel
- Hand saw
- Table-mounted woodworker's vise
- Pencil
- Safety glasses
Instructions
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1
Begin by aligning the two boards into their final position, with one board butting into the other. With a pencil, lightly mark the outline of the butting board onto the face of the receiving board.
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2
Within the confines of the outline you drew in Step 1, draw an outline for the mortise, or slot, to be cut into the receiving board. This slot should be in the center of the outline, and the area inside the slot should be at least half the area of the tenon board's outline, but not greater than three-quarters of the area. This mortise slot will generally follow the shape of the tenon board; in other words, a square board should have a square tenon, while a rectangular-shaped board should have a similarly-shaped rectangular tenon.
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3
Using a sharp chisel, cleanly cut out the area of the mortise marked in the previous step. Work slowly, using your hammer to tap the chisel and remove stock inside the mortise. For a through tenon, cut your mortise all the way through the board. For a blind tenon (where the tenon will not be seen on the backside of the board being mortised), cut the mortise about two-thirds through the thickness of the board.
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4
Transfer the marks from the mortise to the end grain of the tenon board. Also, mark the desired length of the tenon on the faces of the board (as it may be cut to be flush with the back side of the mortise, or it may be extended beyond the mortise, depending on the desired style).
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5
Cut each of the four faces to the desired depth (from the face to the depth of the outline) using a hand saw. Be sure to cut evenly, keeping the cutting edge of the saw blade square to the face. These are referred to as the shoulder cuts.
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6
Clamp the board into a woodworker's vise (or use an alternative method for securing the board in a vertical position). Cut straight down evenly through the end of the board on each of the four marks for the tenon until you meet the shoulder cuts, and remove the cut material. These are called the cheek cuts.
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Test fit the joint by slipping the tenon into the mortise. The fit should be snug but not too tight. If the joint is too tight, you can carefully cut a slight bit more off of each of the cheek cuts. This may be easiest with a chisel.
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Tips & Warnings
Always cut the mortise before cutting the tenon, and cut the tenon a little proud. You can always take a little more off of the tenon to make a proper fit, but it's not possible to fix a loose joint if you cut too much off of the tenon.
Many woodworkers prefer to use power tools to make mortise and tenon joints. A dedicated mortising tool (a modified drill press with a square chisel surrounding a drill bit) is used to make the mortises. A table saw can be used with a special tenoning jig to make the tenons.
Always wear safety glasses when doing any kind of woodworking.
References
- Photo Credit mur grange image by musicorso from Fotolia.com
