Tc 9-524 fundamentals of machine tools

Surface Grinding
Surface grinding is the grinding of simple plain surfaces.
Tool and Cutter Grinding
Tool and cutter grinding is the generally complex operation
of forming and resharpening the cutting edges of tool and
cutter bits, gages, milling cutters, reamers, and so forth.
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TC 9-524
The grinding wheel for any grinding operation should be
carefully chosen and the workpiece set up properly in the
grinding machine. Grinding speeds and feeds should be
selected for the particular job. Whenever practical, a coolant
should be applied to the point of contact of the wheel and the
workpiece to keep the wheel and workpiece cool, to wash
away the loose abrasive, and to produce a better finish.
GRINDING SPEEDS AND FEEDS
In grinding, the speed of the grinding wheel in SFPM and
the feed of the grinding wheel are as important as, and
sometimes more important than, proper wheel selection.
Occasionally, the grinder spindle should be checked with a
tachometer to make sure it is running at its specified RPM.
Too slow a speed will result in waste of abrasive, whereas an
excessive speed will cause a hard grinding action and glaze
the wheel, making the grinding inefficient. The feed of the
grinding wheel will determine to a cetain extent the finish
produced on the work and will vary for different types and
shapes of grinding wheels.
Factors Governing Speed
W A R N I N G
If a wheel is permitted to exceed the maximum safe
speed, it may disintegrate and cause injury to the
operator and damage to the grinding machine
The various factors governing the speed in SFPM of a
grinding wheel are as described below.
Safety
The grinding wheel should never be run at speeds in excess
of manufacturer’s recommendations, Usually, each grinding
wheel has a tag attached to it which states the maximum safe
operating speed.