A vise for holding small articles while filing can be made as shown in the illustration. The vise consists of three pieces of wood, two for the jaws and one a wedge. The hinge for connecting the two jaws is made of four small screw eyes, two in each jaw. When locating the place for the screw eyes, place the two in one jaw so they will fit between the two of the other jaw. Put a nail through the eyes when the jaws are matched together and they are ready for the wedge in clamping the article to be filed.
Contributed by John G. Buxton, Redondo Beach, Calif.
Detector for Slight Electrical Charges
Aluminum Foil in a Bottle
A thin glass bottle is thoroughly cleaned and fitted with a rubber stopper. A hole is made through the center of the stopper large enough to admit a small brass rod. The length of this rod will be governed by the shape of the bottle, but 3-1/2 in. will be about right. The bottom of the rod is bent and two pieces of aluminum foil, each about 1/4 in. wide and 1/2 in. long, are glued to it. The two pieces of foil, fastened to the rod, are better shown in Fig. 2. Fasten a polished brass ball to, the top of the rod, and the instrument is ready for use. Place the article which you wish to test near the ball, and if it holds a slight electrical charge, the two pieces of foil will draw together. If it does not hold a charge, the foils will not move.
Transcriber's note: The foil pieces will move apart, not together.