Electric Drill

One in which the motive power is furnished by an electric motor geared to the drill, so as to form a light and efficient tool. Feed screws of different pitch are furnished for varying the speed of boring and a friction clutch protects the motor, should any hard material be struck suddenly. In bituminous coal the drill shows a speed of from 5 to 7 ft. per minute. In "boney" coal, about 3 ft. per minute, and in anthracite ab. 6 ft. per minute. The drill complete weighs from 100 to 160 pounds, and thus meets the requirements of strength, lightne , capacity, ease of action, adjustability, practicability, and economy. IMG:content-1279.jpg:[merged small][merged small][graphic] IMG:content-1280.jpg:[graphic] IMG:content-1281.jpg:[blocks in formation] Electric Battery. See gas.