# Page:Popular Science Monthly Volume 90.djvu/955

Popular Science Monthly

��Finding the Speed of a Worm-Gear with a Bit

IN making some experiments with a small machine it became necessary to use a worm-gear for a transmission. The follow- ing method was used to determine the speed required. The shanks of several broken bits were cut oflf as shown at A and connected with the motor by means of flanges, each one in turn. With the use of different sizes of

���The twist of a bit drives a straight-cut gear for determining reqviired speeds

gear-wheels and bits the speed desired was easily obtained. Such a gear has been used on a larger machine with excellent results. — E. J. Bonis.

��Measuring Through Obstacles by the Triangulation Method

IN trying to find the length of a pipe for laying a line under a house or other building it often happens that difficulties are encountered which prevent direct measurements. In such cases the following method may be used: In the illustration the line A-B is the one to be measured, C being the obstacle that prevents direct measurement. At the point D both A and

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�B

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��Finding the length of a pipe through an obstacle by the method of triangulation

B can be seen. First, sight from point A over D, and beyond for a distance equal to A-Dy to £. From B repeat the opera- tion, making the distance D-F equal to B-D. The line G when measured will be found to be the same length as the line A'B. — Paul I. Kennedy.

��939

Making a Small Syringe to Clean Lubricator Glasses

THE small lubricators usually attached to small stationary engines do not as a rule have a drain-plug or valve at the base of the feed-glass for cleaning it. This makes it necessary to "blow back" through the feed-nozzle to empty the oil. I was recently work- ing on a small engine having a lubricator of the above type, and in connection with the lubricator, due to poor run of feed water at times, the feed-glass fre- quently filled with sediment, making it impossible to see the feeding drops of oil or to know whether it was working.

The drawing shows a small emergency syringe made from a lead pencil and a strip of moderately heavy oiled paper. A piece was cut off from the end of the pencil and the lead pushed out to make the nozzle. The other part of the pencil was used as a plunger or piston. It was not necessary to empty the oil from the lubricator in order to "blow back" to clean the glass, for the water and sediment were quickly drawn out by simply removing the small cap nut. The lubricator started as soon as the glass was again filled with the small amount of necessary condensation. — F. W. Bentley.