A tenon is a wood joint consisting of a cylindrical-shaped “tenon” (a protrusion) cut into the end of a wood piece and then inserted into a mortise for jointing woods. The gap between them gets filled up with wood shavings, sawdust, plaster, or other suitable material like a dowel bar. Usage of glue ties them up to ensure strong joinery. Here I’ll show you how to cut tenons in different methods step by step.
Tools for Cutting Tenons
- Tenon saw
- Sliding bevel saw
- Saber Saw
- Table saw with a blade guard and unguarded blade
How To Cut Tenons: Different Methods
The first method for cutting tenons is to use a panel, along with a bunch of clamps and glue. First of all, what you have to do is to coat the edges of your tenon before inserting it into the mortise. Then gently clamp them together at either end. If you’re using slotting jig clamps for this step, don’t tighten more than six turns on each clamp at a time. It might cause the breakdown of your tools.
Saw down one side of the tenon until it is about 3/4″ deep and wide enough to accept a dowel bar. It will function as the key for the glue joints. Set it aside to dry while cutting out the mortise in another piece. And set both pieces aside while they dry completely (this can take as long as a day depending on your climate and humidity). When the tenon and mortise are ready, bring them together up against each other. Line up the slot on the tenon with the mortise, then tap the side of the tenon with a hammer to seat it in place. You can use a pen to mark any gaps between the joints. These gaps will be a good fit to wedge. Apply some thin wedges in place so that the joint becomes tight before applying glues.
The second method for cutting tenons is to clamp both pieces together, keeping the tenon on the outside. Use a rectangular pad clamp to hold them tight together. Apply glue between the tenon and the mortise, then have someone assist you in turning them over before clamping it again for the final tightening of the joint.
The third method for cutting tenons is to use a slotting jig to hold two tenons together with slots facing each other.
The tenon is inside with the mortise cut into it. Use a circular clamp to place a dowel bar in the feed slot and clamp it down firmly. This method keeps the joint tight before gluing it together. You can also use clamps for this step if you’re not using slotting jig clamps.
After the joint is set, use a chisel, or block plane to remove excess material to give the joint a uniform 3/4″ depth. You should remove excessive shavings from the tenon and clean it. And don’t allow them inside the wood pieces. It may take too much space and create voids.
The standard measurement says that the tenon and the mortise measure 1″ wide and approximately 3/4″ depth when cut completely. If you want to adjust the width once cut, use a chisel to shave off as little material as possible. Be sure to check your joint every time you remove more wood. Scraping away material can make it too deep for the mortise to accept or make it slack. And there isn’t enough glue surface to adhere properly.
When you see the joint is tightly fit, apply some glue to both surfaces and clamp it down firmly. When the glue gets dry after a few hours, test it for tightness by pulling on the tenon; the mortise shouldn’t move or shift. If it does, you need to add some more glue to the joints and clamps.
Instructions For Cutting Tenons
- Ensure that both sides of your tenon are clean and dry.
- Apply glue to the joint, pressing firmly to ensure an even coat all across the tenon’s surface.
- Clamp both pieces together with the tenon on the inside, using a clamping fixture or a table saw with an unguarded blade that allows you to cut through the material easily (for slotting jig clamps, use six turns only). Allow them to dry for at least 24 hours before re-clamping them together. We recommend you use a clamping fixture to hold the pieces together tightly. However, if your mortises are particularly small and difficult to clamp, you can hold the pieces together with wedge clamps. You’ll need four of these little clamps. First, create slots or chamfers around the edges of your tenons; then glue them in position. Wedge clamps are placed on the tenon’s edges and tightened gradually until the joints accept glue.
- When you’re ready to lock your joint together, apply more glue to both sides of your tenon. Then, use a pen to mark small gaps between the mortise and tenon. You can implement these gaps with thin wedges in place.
- Use a chisel or block plane to remove material from your tenon until it reaches its desired depth. Apply glue to your mortises and leave them open for 24 hours before inserting your tenons.
- When you’re ready to insert the tenons, use a pencil or pen to mark a line around the edge of each mortise. This line will guide cross-cutting tenons in half.
- Use chisels or a block plane to clamp securely in place. Cut around the line you previously drew.
- Remove any excess shavings or sawdust and check the fit of your newly cut tenon before placing glue in the mortise.
- Ensure both sides of your tenon are clean and dry before applying glue.
- Insert the tenon into its respective mortise, then tap it firmly with a hammer.
The tenon-cutting process is straightforward. You should know that the size of tenons will vary on what you’re making it for. If you are having trouble getting a tight joint, it might be due to the lack of clamps or too much glue. Also, do not forget to test your joint before the final setup. If it’s not tight enough on the first try, undo it and re-cut until it fits tightly into the mortise.