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Page:Popular Science Monthly Volume 90.djvu/462

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��Popular Science Monthly

��ment. The first cost for installing the machinery is the greatest expense. The up-keep amounts to very little, especially if the owner is fortunate enough to secure the services of an intelligent man-of-all-work, one who is handy with tools and can make ordinary repairs when necessary. On this particular farm the handy-man was the inventor of the tank heater for the engine- house and watering trough. He also fitted up the family surrey with electric lights, fitting the tiny bulbs into the lamp- wick sockets, and connecting them with dry cells placed under the front seat. A home-made switch turns on both lights at once.

��Foot-Power Jig-Saw Made from a Sewing Machine

AN old sewing machine that had out- jLjL lived its usefulness in that capacity and was to be discarded made the ground- work for the jig-saw as shown in the illus- tration. The shuttle, the mechanism driving the needle-holder and the step v/ere removed. Only the hand-wheel together with its shaft and cam-disk at the end were used.

The frame of the jig-saw consists of two arms 21 in. long, ^ in. wide and 3^ in. thick. Each piece is drilled through the width, making three holes, one 3/16 in. in diameter }/2 in. from the rear end, one 15 in. from the same end, and one 3<C in. hole 3^ in. from the opposite end or front end of the frame. A i/i6-in. hole is made in the side of the upper piece 4}/^ in. back from the front end. The two pieces are held together at the rear end and 6 in. from the front end with bolts having long threads on each end and a


��The frame of the jig-saw for attaching to the sewing-machine table and head for small jobs

nut on both sides of the stick. The rear end bolt is made up of two pieces, each 2}4: in. long and 3/16 in. in diameter with threads on both ends, i}^ in. in length on one end and 34 in. on the other. The shorter threaded end is turned into a hole tapped into the side of a round piece of

��iron that is ^ in. long and ^ in. in diam- eter. The piece is also drilled centrally with its length for a 34-in. bolt. This bolt runs through a standard io3^ in. long, ^ in. wide and 3/16 in. thick that is fastened

���The frame on the sewing machine where it is driven by a crank attached to the head shaft

to the base plate of metal running beneath the sewing-machine top. This latter plate is 21 in. long, i3^ in. wide and 34 in. thick. This is fastened to the top with a thumb- screw turned into a tapped hole in the metal sewing-machine base.

In the outer ends of the saw-arms are placed screws which are centrally drilled for the saw-blade end and a set screw affixed to clamp the saw in place. The sawing table is made up like a three-legged stool, the top being a round disk 6 in. in diameter and 34 in- thick. To prevent the saw blade from lifting the board up at each stroke a guide is used above it. The guide consists of a 3/16-in. rod bent L-shaped, one end being flattened and the other having a long thread cut in it. A bar fastened to the lower part of the square frame on the sewing-machine head makes a support for this guide.

A short pitman is used on the cam-disk to drive the frame. The shaft and cam- disk are, of course, driven by the usual treadle, wheel and belt drive that was originally used on the sewing machine.

While this arrangement does not give any great swing in the opening under the sewing-machine head it can be used on a great many pieces for building up small work. — E. M. Davis.

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