Woodworking angle joints (Part 2)
The Mortice and tenon joint
In its varied forms, this joint is used perhaps more extensively than any other. The picture of the mortice and tenon joint (Fig A) shows the names of the different parts of the joint.
- The Shoulder
- The Tenon
- The Mortice
A Stub tenon (Fig B) is a tenon that does not go through the timber. It needs holding in position by a dowel or metal fastening. This is used for only simple frameworks and in situations where you would not want to see the edge of the finished joint.
In most cases, the tenon would be fixed with wedges, as well as glue. A through wedged mortice and tenon joint (Fig C) increases the surface area of the joint for gluing purposes and is our preferred joint for our wooden gates. Wedge space is cut into the mortice, the tenons are glued and inserted into the mortice and the work is cramped up. Wedges are then driven into the mortice from the outer edge of the timber.
Another method of wedging a mortice and tenon joint is the foxwedged mortice and tenon (Fig. D). Wedges are driven into saw cuts in the tenon; the disadvantage with this method is the fact that if the wedges are driven in with too much force, then the rail (from which the tenon is cut) can split. With this method, it is also best to leave the cramps on the work until the glue has dried, again due to the fact that the wedges cannot be driven too far in.
When the joint is at the end of a piece of framework, a haunched mortice and tenon (Fig. E) is used. Mainly used in door construction and used in the construction of our wooden garage doors, the use of a haunch reduces the width of a tenon and enables it to be wedged without any appreciable loss in strength. For wider centre rails, a different type of haunched tenon (Fig. F) is used for more stability.
Known as Secret Tenons, below are two methods of fixing a stub tenon by fox wedging. The first method (Fig. G), shows the wedges in position in the tenon prior to being fitted into the mortice, alongside a cross section of the timber with the tenon in place in the mortice. The joint requires careful preparation both for length of tenon and size of wedges, as it is difficult to rectify any mistakes after gluing and wedging up. The second method, shown as a cross section through the timber (Fig. H), shows a simpler method. The disadvantage is that the end of the wedge will be seen.
The final joint we will be looking at in this post is the Drawn Tenon (Fig. I). Not to be confused with a dowelled mortice and tenon, the drawn tenon is also known as draw-boring. The drawn tenon is used where there is difficulty in cramping up the joint and in situations where there is a likelihood of the work needing to come apart at a later date; this was the traditional method of making wooden field gates, as if the gate was damaged by animals, then the gate could easily be taken apart and the damaged pieces replaced. The pin is used to ‘draw up’ the joint. The hole is first bored into the cheeks of the mortice, when this has been done, the tenon is fitted into the mortice and the centre of the hole is marked onto the tenon. The tenon is removed from the mortice and the hole is bored into the tenon off centre – a little nearer the shoulders of the tenon than the mark made. As the pin is driven through the mortice and tenon, the shoulders of the tenon are brought close to the mortice. If you intend to take the joint apart at a later date, then glue would not be used.
Even more woodworking angle joints in part 3, including the bridle joint, tusk tenon and a couple more!