Page:Popular Science Monthly Volume 90.djvu/592

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��Popular Science Monthly

��Grind Your Valves at Home. A Machine Made for Car Owners

��GRINDSTONE.

��CENTERING HANDLE

���ADJUSTABLE ARM

��MOVABLE SHAFT

��ROCKABLE BRACKET

��The valve head is held at an angle against the rotating grinding wheel which drags it around and bevels its edge into a perfect circle

��AN autbmobile cannot work efficiently ±\. unless the engine-valves are in good condition? The valves control the supply and the exhaust of the vaporized gasoline in the engine cylinders, and if they should wear unevenly and begin to leak, the maxi- mum amount of power cannot be obtained from the fuel. Hence the valves should be ground often,

A machine for grinding the engine valves accurately and rapidly has recently been invented. The valve-heads, which must be ground perfectly round so that they sit tight against the circular ports or openings in the cylinder, need only be adjusted in this machine, and the grinding will proceed automatically. Evidently such a machine would enable an autoist with average mechanical skill, to grind down the valves of his own car.

The illustration shows a valve-head adjusted in position in the machine. An emery grinding-wheel is rotated at the front end and the head itself is held in place by a holder at the other end. The holder can be moved length- wise in its bearings, while the turn-table on which it is mounted al'ows it to be swung at an angle to the plane of the grinding wheel. The valve-head is pivoted be- tween two steel points on the holder so that it can freely rotate on them.

A small electric tu r * u, r u- , •

^ 1 • I • The tront wheel of a bicycle is removed,

motor, wnicn is placed in the rear, belted up with the other

geared to the and an exerciser for leg muscles is made

��grinding-wheel, is then turned on. The revolving wheel, with the edge of the valve- head in contact with it, drags the head continuously around. At the same time, the wheel continuously "strikes off" side- wise from the edge of the valve-head and consequently bevels it down. The valve- head rotates always a fixed distance from the plane of the grinding-wheel, so that a perfect circle will be obtained on the head.

A person of only ordinary skill can grind a valve with the machine described, on account of the fact that the valve is always in the proper position with relation to the grinding wheel. Any standard valve can be ground quickly and easily, as the only change in the machine's adjustment is to adapt it to a long stemmed valve or a short stemmed valve. This is done by changing the position of the arm on the shaft.

When valves having stems of about the same length are being ground it is not necessary to change the position of the arm, in view of the fact that the socket member is adjustably mounted in the arm.

���The Bicycle to the Rescue in Leg Treatments

ONE of the simplest devices yet heard of for restoring strength and agility to soldiers' legs after they have recovered somewhat from the effects of wounds, is utilized at an electrical gymnasium which has been started at Chateau D'Oek, in Switzerland, by a French Adjutant and C. S. M. McCarty _ (Leicester Regiment), in the interest of British soldiers who have been wounded and are convalescent. The bicycle employed for the purpose need not be of the latest model. Only the frame and the two wheels are necessary. Not even tires are required. The front wheel is taken off and the frame is fastened to a stationary sup- port. The wheels are arranged at the rear as shown in the accompanying illustration. The tires are re- moved and a belt or rope support- ing a weight is carried over the wheels.

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