Art Metalwork Chapter 10

SAW PIERCING

Before continuing with the series of graded problems, attention may be called to two supplementary problems similar to the bookend described in Chapter 9.

The clock, Fig. 22,

is made in exactly the same manner as the book-end; a design is etched on the metal, the edge lapped over, and the base bent back in precisely the same way. It should be noted, however, that the base of the bookend is bent back exactly at right angles, while the clock is bent back at about 70 degrees. Any small round clock may be used; those in the illustrations cost $1.00 each.(In 1914!) The legs and handle may be taken off by unscrewing, and it is then read to fit to the copper holder. Mark on the copper where the clock is to go a circle that is exactly the diameter of the clock, and inside this another circle that is 1/2" less in diameter. Next, cut out the shall cir cle is smooth as possible, either with the small chisel that was used to cut out the strap-hole on the watch-fob, or, better yet, cut, it out with the saw-frame described later in this chapter. If necessary, smooth off the edge with a file, then with the ballpein hammer on the lapping- stake turn back the extra stock to the circle that is the actual diameter of the clock, as shown in the drawing, Fig. 28, and fit the clock in tight and snug. Color and finish in any of the previously described methods. Fig. 24

shows another suggestive treatment of the clock problem.

The other supplementary problem is that of the letter-rack, Fig. 23,

which will require a piece of 18-gage copper or brass 10" long by 6" wide. A design may be etched on the front, which is 3 1/2" high by 6" wide; the back is 4" high and the bottom is 2 1/2" from front to back; these roportions may, of course be varied slightly. The edges of both front and back may be lapped or left plain, as in the case of the book-ends. It is better and easier
to lap the edges while the metal is flat, being careful not to make the mistake of lapping the back and front both the same way, because they will be opposite when bent up into shape. They should be lapped as shown in the drawing, Fig. 28. The front may be bent up as in the book-end, but to bend up the back a piece of hardwood will be needed—the end of a piece of 2x4 about 10" long world do. Bend up the back, color, and finish.

There are numerous other problems supplementary to this course. Among them is a desk calendar made on the same principle as the clock with a narrow strip riveted on to hold the calendar, also a calendar-pad holder; but enough has been said of supplementary work to show the wide variety of useful objects that can be made, and the artistic possibilities.

When making the next of the graded problems, which is a hinge, we shall need, in addition to the tools already described, the following new tools, Gig. 205:
No. 65, Jeweler's saw-frame, 5" deep, costing $0.70
No. 2, Jeweler's saw-blades, 1 dozen 0.10
No. K, Stake, rough cast, 15c, polished 0.40
No. 27, Prick or center pinch 0.10
No. 82, Hand-drill $1.25
Drills from 3 cents to 7 cents, according to size.
1 piece of wood, 3/4" thick, 3" wide, 8" long, for a saw-board.

When designing a hinge, Fig. 26,

it must be remembered that the first requirement is that it shall be strong enough to carry easily the door or cover for which it is made. No standard dimensions can be given, for hinges vary considerably in size and proportions according to the purpose for which they are made and the space they have to fill. Generally speaking, there are three styles of binges: the butt hinge, in which both ends are the same, and relatively short; the strap hinge, in which one end is elongated —sometimes both; and third, the T-hinge, one of which is shown in the drawing, Fig. 28. Examples of butt hinges and strap hinges are shown in Figs. 26 and 27.

We will take for a description of the process the making of a strap hinge. Hinges consist of four parts : the butt, which is the short end; the strap, which is the long end; and the knuckles, which fit together and are held together by the pin. There are usually five knuckles, three on the butt and two on the strap end. In other words, three knuckles on that part which is stationary when in use, and two knuckles on that part which moves.

First make a full-size drawing of the hinge, then by means of transfer paper transfer the design of the butt end to the copper or brass. Then lay out the knuckles as shown in Fig. 28, by measuring the outside diameter and laying off three times the diameter, which will, when bent around into the knuckles, be approximately the required size. Transfer and lay out the strap in the same manner.

Saw out the hinge with the jeweler's saw. This process of sa w-piercing will require considerable care in observing a number of details ; otherwise the beginner will break a number of the small, fine saws. To place a saw in the frame, first be sure that the teeth point toward the handle. This can be determined by careful inspection, as the teeth are shaped like those of the wood-worker's rip-saw. Fasten the saw in the top clamp of the frame and push the top of the frame against the edge of the table or bench, and the frame will give or spring just a little; then fasten the lower end of the saw in the bottom clamp. When the pressure is released, the spring of the frame will pull the saw tight. The saw will break in the work if it is not stretched tightly.
Take a small piece of metal and practice sawing before starting to saw out the hinge. Fasten the saw-board to the work-bench with screws, nails, or, better yet, with a clamp that can be bought for 10 cents. Hold the Metal flat on the board with the saw in the V-shaped opening in the board and start sawing, remembering that the cutting is all done on the down-stroke.

Be sure to keep the saw-blade at right angles with the metal, and moving at the rate of about two strokes per second. When changing the direction of the saw, always keep it moving up and down. This is very necessary, as the saw will break if it is twisted while still. If the saw sticks and binds, a little beeswax rubbed on the blade will sometimes help.

To saw out the ornamental openings in the hinge, it will be necessary to punch a small hole thru the metal with the prick punch; then unfasten the saw from the bottom clamp and insert the saw in the small hole in the metal, spring the frame again, fasten the saw in the clamp, and proceed to saw as before. When both parts of the hinge are sawed out, bend the ends of the knuckles over oil the K-stake, and continue bending until they are as nearly round as you can get them. Then get a wire nail that is large enough to fit the knuckles tight and hammer them smooth and round and fit the two ends of the hinge together. Push in and cut off a wire nail for the pin, to hold the knuckles together, then hammer the hinge smooth with either end of the ball-pein hammer. Locate the holes for the screws to fasten it to the article for which the hinge was made. With the prick punch make a small hole, and with the hand-drill drill the holes. Color and finish in any of the methods previously described.

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