Page:Popular Science Monthly Volume 89.djvu/634

 620

��Popular Science Monthly

��How to Avoid Exessive Oiling in Automobile Cylinders

WHEN the cylinders of a motor- cycle or automobile show the effect of excessive lubrication, the fault is often in the piston-rings. In order to permit the super- fluous oil to run back into the crank-case, the following scheme has been found very effective.

Turn a narrow groove in the lower part of the piston, with the lower edge beveled. Then bore six or sev^en holes at equal distances around the piston, at an angle through the groove. The sharp edge of the groove scrapes the inside of the cylinder clean, and the excessive oil returns through the drilled holes into the crank-case. It is self-evident that no piston - ring is fitted into this groove.

This method of avoiding excessive oil- ing will be found particularly efificacious in old-style cars, which have been run for a number of vears.

���An extra groove in bottom of the piston

��A Novel Experiment with a Lamp-Bulb

AVERY weird and interesting experi- ment may be performed with a lamp bulb. The materials needed are a motor or other means of rotating the bulb, at fairly high speed, and the incandescent lamp-bulb and its socket. All bulbs will not work in this experiment as tile \aruum must ])e right. Most bulbs that are now manufactured have too high a vacuum, but if the experi- menter has an old bulb made sever.il years ago, it will prf)!)ah!y work well.

��The method of mounting the socket on the motor -shaft is shown in the illustration. The socket is threaded for 3^-in. gas pipe which is about % in. in diameter. If the motor-shaft is the same size and is threaded it can be screwed right on. If not, a hard rubber or fibre bushing can be used. The hard rubber bushing which is used with the socket is shown in the detail. This should be screwed into the socket and a hole bored in it below the set screw hole. A screw with the same thread as the set screw and long enough to reach the shaft through the bushing may be used for the set screw. The inside of the bushing can be enlarged with a rat-tail file to fit very tightly on the motor-shaft. The set screw should be turned up tight against the shaft through the bushing. The bulb should -^.^.W/ now be placed in the socket and ro- tated, the hand being held against it. If the hand is damp it should be allowed to heat up by the friction until it is quite dry. The pressure of the hand need not be great. If the bulb is right it should light up with a pale violet hue. It appears to work best if the hand is held on one side of the bulb only and does not completely encircle it. Sparks may be observed between the bulb and the hand and also where the filament touches the bulb. It is needless to say that the should be quite dark.

���^jA-.-y

��Mounting the socket on the motor-shaft

��room

��Prolonging the Usefulness of a Saucepan Cover

WHEN a saucepan cover seems use- less because the little knob or handle is lost, push a cork part way tliroui;h the opening and secure it by dri\ing a nail i or i^ j in. long horizontally through the cork on the under side.

��The Editor of the POPULAR SCIENCE Monthly is always glad to hear from readers who have made simple and useful things for the home and the shop with their own hands and who would like to tell others of their own success. Articles from amateur mechanics, electricians and wireless operators are paid for on ac- ceptance, promptly and liberally. But contributors must understand that only un- published contributions, offered exclusively to the POPULAR SCIENCE MONTHLY, are desired.

�� �