How to Cut Wide Tenons

This is an excerpt from “The Woodworker: The Charles H. Hayward Years: Volume III” published by Lost Art Press. 

A reader has been making a piece of work which has involved the use of a tenoned rail some 12 ins. wide, and tells us that he has had difficulty in sawing the tenons. Whilst it is possible to saw the tenons, we should not advise it. It would take too long, and it would be difficult to keep the saw true across so wide a tenon. We give here the simplest method.

We show a wide rail in Fig. 1, the cutting of the double tenons of which is a typical example of the process to be followed. A similar case of even wider tenons is that of, say, a table top with clamped ends, the last named being mortised for tenons cut at the ends of the top.

Mark out the joint in the usual way, squaring in the shoulders and marking the tenons with the mortise gauge. The chisel is used for marking the shoulders, and a shallow sloping groove is cut on the waste side as at X, Fig. 2. This forms a convenient channel in which the saw can run when cutting the shoulders, the next operation. The tenon saw can be used for this. Saw down to a fraction short of the gauge line, and be careful to keep the saw square.

Assuming that the grain is reasonably straight, chop away the cheeks with a chisel as at B, Fig. 2. Do not attempt to remove all the waste in a single cut, but start the chisel about halfway down, and finally take it to within about 1/8 in. of the line. Of course, the grain must be watched. If it tends to run downwards the chisel cannot be used so close to the line. If it runs upwards, it can be taken almost on to it. A fairly wide chisel is desirable for this work.

Now take the rebate plane and work across the grain, the side of the plane pressed against the shoulder as in Fig. 3. If you have the metal type of rebate plane you can set the depth gauge so that the plane ceases to cut when the tenon is reduced nearly to the gauge line. Be sure that the cutter does not project on the shoulder side as this will damage the latter. At the near side the grain is sure to splinter a bit, but this does not matter. It cannot splinter on the shoulder side as it has already been cut with the saw.

To finish off use the jack or any other bench plane as in Fig. 4. Carried out in this way the reduction of the wood is quite rapid, certainly quicker than when the saw is used throughout, and it enables the tenon to be trimmed to within fine limits. The remainder of the work, that of cutting the separate tenons and the haunches, is as in normal tenoning.

— MB