Types of Sharpening Stones and Oilstones.

Use And Care Of Handtools And Measuring Tools
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b. Types of Grinders.

(1) Bench Grinder. A bench grinder (figure 62 on the following page)

is a device with an axle to mount an abrasive wheel and a handcrank that

will permit turning the wheel.

The grinder is geared so that the wheel

spins faster than the crank. This type of grinder is clamped onto a bench

and is equipped with a rest for alignment of the work when grinding.

(2) Mounted Grindstone. The mounted grindstone (figure 62) is foot-

powered.

The nonglaze grit stone is 2 inches wide and 22 inches in

diameter.

A funnel-shaped container of water, which constantly wets the

stone during grinding, is suspended over the stone.

(3) Valve Grinder.

The hand valve grinder (figure 62) is a device

that is used to lap engine valves in their seats.

It consists of pinion

gearing enclosed in a heavy, machined, cast iron housing. An external crank

handle drives the gears, which rotates a shaft.

The end of the shaft is

designed to hold any one of three driving blades for use on slotted valves.

Nonslotted valves can be driven by a rubber suction cup, supplied with the

grinder, that fits the shaft. Two shafts are furnished; one short and one

long.

c. Types of Sharpening Stones and Oilstones.

Sharpening stones and

oilstones are natural or artificial stones. Most sharpening stones have one

coarse and one fine face and are normally made of silicon carbide, aluminum

oxide, or natural stone. Natural oilstones have a very fine grain and are

excellent for putting razor-like edges on fine cutting tools. Some stones

are mounted and the working face of some of the sharpening stones is a

combination of coarse and fine grains. Stones are available in a variety of

shapes, as shown in figure 63 on the following page.