Figure 2.48.
Combination square
2-11. Sharpening and Smoothing Tools. Two main types of tools are
used to sharpen and smooth other tools: stones and files.
a. Grindstones. Most bench grinders found in carpentry shops are
equipped with two grinding wheels: one of coarse grit and one with
fine grit. Grinding wheels are held to the shaft by nuts, which
squeeze the wheel between two special side washers. Grinding wheels
are also rated by the turning speed they can withstand. Be sure you
use stones made to withstand the rated revolutions per minute of the
grinder electric motor. A tool rest is attached to the grinder frame
and is adjustable for height as well as for distance from the stone.
Most grinders are equipped with heavyduty glass guards to permit
watching as you grind. If there is no eye guard, you must wear
safety goggles to protect your eyes. It is considered poor practice
to use the side of the wheel for grinding. When the surface of the
stone becomes irregular or filled with metal particles, use a stone
dressing tool (Figure 249) to restore a good grinding surface. A
water container, attached to the base of the grinder, is used for
cooling parts being ground. Always cool the blades of tools you are
sharpening to prevent destroying the temper of the metal with the
excess heat generated from grinding. Heavy grinding is done on the
coarse wheel, and light or finishtype grinding is done on the fine
grit stone. Most cutting edges should be finished by hand, using a
fine oilstone.
EN5155
2-26
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