Page:Popular Science Monthly Volume 90.djvu/950

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��Popular Science Monthly

��Finding Leaks Quickly in Air Tanks

��WHILE visiting a rock quarry I saw the workmen using a new method for finding leaks quickly in compressed air tanks. A plug was removed in the upper part of the tank and a large spoonful of oil of peppermint poured in. The plug was screwed back in and the compressor started. The leak was soon found by the odor of the peppermint. This method may be used to advantage for finding leaks in small acety- lene lighting plants. — Edward Gyger.

��Making a Bulb Planter from a Foot Pump

THE foot pump should have an mside diameter of at least 1 3^ in. The plunger is taken out and a hole bored through the

base to ac- commodate the plunger rod. The handle then being fast- ened to the end of the rod, a piece of i-in, pipe is bolted on

��to the part which nor- mally is held down by the foot but now serves as a handle. The upper end of the pump where the cap was removed is then sharpened on the edge of the tubing so that it will enter the ground easily. In using this planter the pipe is held in both hands and pushed into the ground to the

desired depth, which for bulbs is about 5 or 6 in. The wood handle then rises and indicates the depth of the hole. On with- drawing the pipe from the hole a solid core of earth is left in the end of the pipe which may be easily expelled.

���Inverted foot-pump used as a bulb planter

��The advantage of this planter is that it leaves a hole with a flat bottom and also does not compress the earth as in the case of a pointed stick. The maker of this has put in several thousand tulip bulbs with it in dry hard ground very satisfactorily.

Substitute for an Automobile Hub-Cap

APIECE of inner tubing approximately 6 in. in length will serve as a ready substitute for a lost hub-cap until a new one can be provided. Should such a cap be lost there is great danger of the dust and grit collecting on the inside of the hub and causing damage beyond repair to the ball-bearings within. The

piece of tubing is held to the

���Tube covering end of hub to keep out dust

��hub with the aid of wire wound tightly around it, while the other end is closed with wire to prevent the dust entering there. — Adolph Kline.

��A Drill of Self-Hardening Steel for Working Marble

DRILLING holes in marble is very wearing on tools. A piece of the best steel, tempered as hard as fire and water will make it, loses its edge and its size very quickly when used for this work. It is not that the marble is so hard, but the gritty nature of the material acts on the tools like an abrasive. A parallel case is that of machine-shop work on iron castings which have not been well cleaned of the molding sand. Machinists say that the sand wears out tools faster than the hardest iron.

Concerns that make a specialty of marble work, such as switchboard slabs, etc., use drills made of self-hardening steel and find nothing to equal it. A short piece of round or square steel is flattened out to a drill point and is generally used in a ratchet drill following a hole made with a small twist drill. Self-hardening steel can be forged and allowed to cool in air without affecting its temper.

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