Page:Popular Science Monthly Volume 92.djvu/158

 142

��Popular Science Monthly

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���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.

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