Of course, it is constructed of wood. Cedar or redwood is the best kind of timber, on account of its lightness. A piece of 3'-inch stuff 22 in. x 9 in., and two pieces of inch stuff, 9 in. x 2 in. is all the wood that will be necessary. As this bar-frame block willserve for all time, it should be made from well-seasoned timber, neatly dressed and firmly put together. The following are the measurements :--\(\Lambda\) B from shoulder to shoulder in the end pieces, 19 1-8 inches, or the full length of a top bar. C D about 22 inches; A C and B D, 9 inches; E F 8] inches, or the full depth of the length of one side of a frame; G H, 173 inches, or the full length of the bottom bar of a frame. \(a\ b\) and \(b\ a\) are two spiral springs, as shown in diagram No. 2; \(b\ b\) the screws fixing the springs to the block; \(c\ c\), the points of contact with the 9-inch side pieces, A C and B D. \(a\ a\), two screws firmly screwed into the frame block, but projecting about 1 inch, around which the spiral spring is coiled in such a manner, so that the portions of the springs \(a\ c\) shall have full play and capable of extending to a sufficient width to receive the side bars of \(\pi\)y frame. The shoulders at A E and B E must correspond exactly with the projecting shoulder of the frame, both in length and thickness. This bar-frame block can be made as a duplicate by fixing two additional springs and two other side-pieces. Where a large number of frames are to be made, a double frame block is a great advantage in point of speed. With it a very large number of handlings are avoided. Diagram No. 2 is an end of a double bar-frame block--\(c\ a\ b\) and \(b\ a\ c\) are the two sets of spiral springs. The end pieces are shown grooved, and the back tongued into it. It is not necessary to fix the two ends by tongue and groove. Of course, it is both neater and stronger; it also prevents any tendency to warping. If the ends are put on in four lengths instead of two grooved pieces they should be securely fastened with screws. Care must be taken that the side-pieces are at right angles with the edges of the block. This block prevents all twisting in the frames, and the external measurements of frames will be the same without the least deviation. In putting the frame together prepare the top, bottom, and side bars. keeping them in three different heaps. It will not be necessary for the side-pieces to be of one uniform thickness. The springs will adjust themselves to any differences that may occur. Fix to the work-bench one or two bottom bars according to whether a single or double block is to be used. Place the bottom of the block so that the fixed bottom bars shall stand in the measurement G II. If it be a double block it will stand without holding. Over the one or two fixed bars, when the block is placed in position, insert the end-pieces for the frame so the springs will grip them firmly to the sides of the bar-frame block. Next, place the top bar in the shoulders A E and B E, shown in diagram No. 1. The side pieces should come ilush to the point **E**. **Nail** the top bar to each end and three of the four sides will be firmly fixed, then invert the block for the insertion of the bottom bar, and fix it in the ends in like manner to that of the top.