Figure 6-4. Grinders
Do not use a metallic object for testing the soundness of
a grinding wheel.
Always wear eye protection when using a
Stand aside when starting the grinder
motor until operating speed is reached. This prevents
injury if the wheel explodes from a defect that has not
Use light pressure when starting grinding;
too much pressure on a cold wheel may cause failure.
circumference of a grinding wheel unless the wheel is
designed for side grinding.
Use a coolant to prevent overheating the
Do not hold the work so that the fingers
will touch the grinding wheel.
Description of Grinding Wheels. A grinding
wheel is composed of abrasive grains and a bonding
agent, and are graded for coarseness and hardness.
Abrasives. The two types of abrasives
are natural and manufactured abrasives.
abrasives, such as emery, corundum, and diamond, are
used only in honing stones and in special types of
common manufactured abrasives are aluminum oxide
and silicon carbide. They have superior qualities and
are more economical than natural abrasives.
Coarseness. Generally speaking, fine
grain wheels are preferred for grinding hard metals, as
they have more cutting edges and will cut faster than
coarse grain wheels. Coarse grain wheels are generally
preferred for rapid metal removal on softer metals.