Mortise & Tenon Jointery
Previously in the Woodworking 101 section of this blog we looked at a wide range of joinery techniques used in woodworking.
Today, we will narrow our focus and just look at the most common joinery technique I employ in the designing and building of custom furniture, the mortise and tenon joint.
The picture below is a classic example of a mortise and tenon joint. I have used this method to join together a gigantic table leg, table stringers and legs, a wine rack, a mirror frame, and an easel.
A tenon of about 1/3 the width of the stock is considered standard. If the tenon is any wider, the board with the mortise may become too weak, and if the tenon is any thinner, it may become too weak.
The strength of this joint is absolutely amazing. When there is a nice tight fit between the tenon and the mortise, the resulting connection, once bonded together with wood glue, will, for all practical purposes, never come apart. If significant force is exerted on either one of the two pieces of wood, the wood will end up shattering before the joint gives out.
A variation on the mortise and tenon joint I use quite often is the loose tenon joint rather than an integrated tenon. Sometimes it is easier to cut two mortises and simply glue in a piece of stock to complete the joint than it is to cut a tenon out of the end of a piece.
A haunch mortise.
A mitered haunch mortise.
Both the haunch mortise and the mitered haunch mortise are simply variations on the normal mortise and tenon.
If a project calls for a very wide tenon, haunches are used at the ends to stabilize the joint and prevent twisting.
If a piece of furniture must have the ability to be disassembled while still being strong and sturdy a loose wedge mortise and tenon is often used. Often times this method is used to simply add a bit of flair to the piece of furniture.
The tenon part of the joint extends completely through the mortise in the main piece and a wedge is driven through a mortise that was cut into the tenon.
The resulting joint is both strong and beautiful.
Two other variations of the mortise and tenon joint include a pegged tenon and a wedged tenon.
The pegged mortise and tenon is when a couple of holes are drilled through the side of the material and through the tenon, and pegs are driven in, mechanically preventing the tenon from ever pulling away from the mortise. This method also adds a lot of visual appeal to an otherwise normal joint.
The wedged tenon is when thin slots are cut in the end of the tenon, the tenon is then extended completely through the mortise, and small wedges are hammered into the end of the tenon, spreading it out and helping to ensure that it will never become loose.
The joint in the picture above is called a slip joint, a very simple form of the mortise and tenon joint. This method does not require the craftsman to cut a classic mortise, but rather just a slot for the tenon to slide into.
A variation of the slip joint used to attach a leg to the middle of a couch or to attach a leg to a round or half-round table.
And that is probably more than you ever expected to know…
January 22nd, 2009 at 1:31 pm
Oh, I’m glad you wrote this blog. Strangely enough, I was just thinking about mortise and tenon joints yesterday and wondering exactly what they were. As you may recall, I mentioned to you a month or so back about how I won a “Battle of the Sexes” game in part by remembering the term “mortise and tenon” but I didn’t know what they were, and now I do. So, thanks for answering my unasked queries.
January 22nd, 2009 at 2:15 pm
Megan, I am glad I could be of service.
February 3rd, 2009 at 3:16 pm
Jared,
I enjoy seeing your shop pics and reading your 101. Thank you very much and keep it coming!!!
This site and everything you are doing is outstanding. Like you, my father opened the door to fine woodworking for me and eventually I would like to do it for a living too. Some people think withholding knowledge is power in order to ensure their security. You on the other hand share it making you a good steward of the community. The laws of return reward those who do good.
Dan