142 



Popular Science Monthly 



t>iston 



PacKing 

 ring 



Cylinder 



Pressure gage attached 

 to the cyUnder head 



Testing Cylinder Pressure With 

 an Ordinary Tire Gage 



OWNERS of automobiles who want 

 to know the amount of pressure in 

 each cylinder 

 of their engine, 

 can obtain this 

 information in 

 a simple man- 

 Rubber washers ner by follow- 

 ing the exam- 

 ple of Sterling 

 Valve seat Waggoner, of 



K/alveattached ^"^^1^^; ^outh 

 J/tovaivestem Dakota. He 

 takes a valve 

 stem from an 

 old inner tube 

 and fastens it 

 into a spark- 

 spark plug base so 

 P'^9 that it is air- 

 tight. Then he 

 holds a tire- 

 gage over the 

 valve, while 

 someone turns 

 over the engine by hand. In a few 

 minutes he determines which are his 

 weak and strong cylinders. 



In making the device, all that is 

 necessary is a threaded connection to fit 

 the spark-plug hole in the cylinder, into 

 which is fitted the extension barrel hold- 

 ing the pressure gage. The air pressure 

 forces up the gage valve which, as is 

 generally known, remains at the highest 

 point. This can be read at any time after 

 making the test until the gage is again set. 



Solution for Removing the Rust 

 from Drawing Instruments 



THE following method of removing 

 riist from drawing instruments is only 

 applicable to those pieces that are spotted 

 with rust and not to those that need 

 regrinding. A saturated solution of tin 

 (stannous) chloride should be prepared, 

 and the instruments permitted to remain 

 in the liquid overnight. They are then 

 rinsed in running water, and rubbed with 

 a chamois skin until thoroughly dry. 

 The rust is removed by the reducing 

 action of the tin chloride. Polishing 

 powder is necessary to restore the original 

 luster of the instrument. 



Portable Scaffold for Putting on 

 Vertical Siding 



ON this scaflfold a workman putting 

 on barn siding, or doing similar 

 work, can remain in a perfectly comfort- 

 able position and nail two or three pieces 

 of siding to three nail ties without having 

 to shift. After this he moves his scaffold 

 into position for nailing the next set 

 of boards by simply sliding it along the 

 top of the upper nail tie as shown in 

 the illustration. 



The scaffold is made of the following 

 material: One board 1 in. by 12 in., long 

 enough to more than reach across the 

 three nail ties; one piece 2 in. thick by 

 12 in. long and just a trifle wider than 

 the top of the nail tie, to be securely 

 nailed to the upper end of the board A; 

 and another piece 2 by 4 by 12 in., nailed 

 to this in such a way as to provide a 

 hook by which the scaffold can be sus- 

 pended to the upper tie. One piece of 

 board 1 by 12 by 16 in. is securely 

 fastened and braced at some convenient 



The scaffold seat is hooked over the upper 

 plate on which it slides to p>osition 



place near the lower end of the long 

 board to provide a platform upon which 

 the workman may stand or sit comfortably 

 while he is nailing on the siding. — JESSIB 

 L. Blickenstaff. 



