The Egan Co.'s Tenoner Machine will make tenons on both ends of a stick at once, besides which, instead of making the tenons by the cutter-heads rather too long, and then cutting them off to the desired length, thus leaving a burr or ridge, it first cuts the stick to the proper length, and thus makes and finishes the tenons, leaving them with a smooth end finish.
In this machine, shown in Fig. 4, there is a bed like an ordinary lathe-bed, and bearing on the left-hand end a fixed, and on the right-hand end a laterally adjustable, housing, each housing carrying two pairs of cutters, on parallel horizontal axes which lie in the same horizontal plane. The front cutter head in each housing bears a cutting-off saw ; the back one, two sets of cutters, one for making each side of a tenon. A hand wheel at the right of the machine regulates the lengthwise distance between the housings and between their cutter-heads to suit the length of stock to be worked. The feed is across the machine, the stock being fed cross wise, and it is effected by sprocket chains along the face of each housing, each chain bearing dogs, the distance between which is adjustable to suit the width of the stock being tenoned. The material is fed away from the operator, and passing under the saws is cut to length ; then passing between the back cut ters, has both sides of both tenons worked on it. Pressure bars over the endless beds, or feed chains, keep the stock down on the latter while it is being cut by the saws and the cutters. These cutter bars will hold the stock clown, even if one end is thicker than the other. The feed, which is automatic in its operation, is driven from a countershaft under the bed, and is controlled by a lever handy to the operator. Suitable provision is made for varying the angle of the cut and the length of the tenon. Each mandrel and slide has separate adjustment up and down on the housings, to suit the thickness of the tenon ; and the upper mandrels have also side adjustment, to allow a tenon to be cut longer on one side than on the other, if neces sary. There are four changes of feed.
The H. B. Smith Co. Double Hand-tenoning Machine, shown in Fig. 5, has a bed much like an ordinary lathe. At one end is a fixed column, bearing upper and lower cutter-heads on horizontal axes. At the other end is a sliding column, bearing similar cutter-spindles. A horizontal shaft, running the length of the machine, drives the cross-feed works, which are endless sprocket chains with projections, carrying the stick—which is presented parallel with the machine—across it and between the two cutter-heads on each end of the machine. Each of these cutter-heads has vertical adjustment independently of the others, so that single tenons may be cut on both ends of the stick at the same time, but varying in thickness and in position on the end of the stick. The feed chain is grooved to receive small angle plates, which, being adjustable in distance apart, may be removed or set to any width of stock. Over the feed are pressure bars. which are adjustable independently of the head, and held so as to support narrow stuff which may vary slightly in thickness. These pressure bars hold the stock down to the angle plates on the feed chain. In front on the left is an adjustable fence against which to support the lumber, so that pieces very close to length may be worked. The rate of feed is about 12 ft. per minute.
In hand-tenoning machines the work is sometimes done by cutters like those of rebating planes, cutting across the stuff, each time taking a shaving from the full width of the stick, and each time leaving a clean, smooth cut, so that at any point at which the cutting is stopped the work is left clean and smooth. Of course, in such work as this it is desirable to take as heavy cuts as possible until the required amount has neaey been cut away, when the thickness of shaving may be reduced in the interest of accuracy of dimension and smoothuess of cut. The power to work these plane tenoning machines may be greatly increased by the use of rack and pinion gears. It is seldom that the foot is used in driving such machinery, the arm being more delicate as regards the adjustment.