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. 



