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Page:Popular Science Monthly Volume 89.djvu/780

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766

��An Improved Grinder for Gas-

Engine Valves

AFTER a gas-engine has been used

±\. for a time, the vaKes, especiall\'

the exhaust members, are apt to become

pitted and scored. In some cases, this

��Popular Science Monthli/ A

���An abrasive wheel supported on a ball bearing shaft for valve-grinding purposes

roughening is so pronounced that it is almost impossible to grind the valves into a correct seating by the usual emery-and-oil process. The valve grind- ing will be considerably facilitated if the valve-heads are surfaced off.

An improved grinder for this purpose, recently marketed, is shown in the accom- panying drawing. An abrasive wheel is supported on a ball-bearing shaft driven by encased gearing in such a way that its speed is fourteen times that of the valve-head and its direction of rotation opposite. The valve is carried by an automatic, adjustable rotating chuck which insures that the valve will be properly centered, this being dri\en by a small pulley from any available power.

The abrasive wheel is properly be\cled to make sure that the angularity of the vaKe-head will not be changed. A cenlt-ring device is included to exert pressure on the \al\e-head and bring it in contact with the wheel. An integral wheel -dresser is also a part of the device. The tool shown has a capacity for valve- stems from 5/16 in. to 1/2 in. in diameter and valve-heads from i 1/2 to 3 in., this range taking in most of the valve sizes in automobile engines.

��H'

��Fire - and-Water Proof Cement for Mending Stove Fire- Brick

ERE is a formula for a cement which will repair fire-brick in stoves and furnaces, and which can be used even where there is an intense heat. Take 3 parts of fire clay and i part iron filings and mix with strong \-inegar until a putty- like mass is formed. If theccmient is used to fill up \ ery small cracks and crexices, it should be thinner. If iron filings can- not be secured, fine iron borings will be just as good. If it is desrrefl to use the cement in a furnace for melting metals, the following mixture will give better results: i part iron borings, 2 parts fire clay, and i part fire sand. Mix with vinegar in the manner described.

��A Revolving Telephone Index on the Transmitter

��EVERY user of certain persons to cal

��a telephone has more or less frequently whose numbers may not be readily remembered. A list of these numbers ma>' not be large and to look them up in the telephone book requires some time. A ver\ handy

���The disk is fastened loosely in position directly behind the telephone mouthpiece

��luimlirrs disk .md

��and ruMt littlt- index Im .1 liw can be written t)n a canlbo.ird slipped on the neck of the telepiione mouthpiece. It has six di\isions and is fitted loosely so that it can be turned. The mouthpiece is unscrewed and taken off to place the disk in position.

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