Wood-working for Beginners: A Manual for Amateurs

by Charles G. Wheeler

To cut the tenon, simply saw carefully on the line gh and its opposite (Fig. 579) and then on the lines lm and rs. Be careful not to cut beyond the line, so as to make the tenon too small. It is easy to trim it a little with the chisel if it is too large. Cut a little bevel around the end of the tenon, so that it will drive through smoothly without catching and tearing the sides or ends of the mortise. When it goes through properly and the tenon and shoulder fit snugly, the projecting end of the tenon can be sawed off after the whole job is done.

The tenon should be just large enough to drive through with a slight pressure and fit snugly without any wobbling around. It should not be so tight as to require much force to drive it home, or there will be danger of splitting out the sides of the mortise.

Fig. 586.

Fig. 587.

Fig. 588.

There is no absolute rule as to how wide to make the mortise and tenon in proportion to the width of the pieces. It depends on the kind of work, the kinds of wood, the kind of strain to be put on the joint, and various circumstances too complex to be gone into here. If the tenon is very thin it will be weaker than the sides of the mortise (Fig. 586). If very thick, the sides of the mortise will be too thin and will be weaker than the tenon (Fig. 587). One third of the width is as thin as a tenon is often made. It will then sometimes be weaker than the sides of the mortise, as you can see from Fig. 588. But it all depends on what the joint is for. If it is to stand violent wrenching, the tenon in this case might break before the mortise-cheeks, and had best be made a little thicker, with the sides of the mortise a little thinner; but, on the other hand, if the joint is merely to hold the tenon-piece in position, as in case of a post resting on a sill, one third is plenty wide enough for the tenon, as it will be best not to weaken the sill by cutting any larger mortise than is necessary. Sometimes the tenon-piece is simply let in to the other piece for its full width. This is called housing (Fig. 589). Two thirds of the width of the piece is thicker than you will be likely to have occasion to make a tenon, as this leaves the cheeks of the mortise very thin. It is wholly a matter of judgment (between, say, one third and two thirds of the width), according to the conditions of each job.