USING ELECTRIC BENCH GRINDERS
The electric powered bench mounted grinder is used to
sharpen tools, dress screwdrivers, and to shape and
smooth metal stock. Avoid grinding of non-ferrous
metals (brass, copper, aluminum, etc.) on the grinder
supplied: special grinding wheels are required for this
The bench grinder available at the sites is equipped with
two different types of grinding wheels. One wheel is
coarse and is used for rough grinding. The other is fine
and is used for tool sharpening and finish grinding.
These grinders are also equipped with safety shields
and tool rests. The tool rest should be adjusted so that
the space between the grinding wheel and the tool rest
is approximately 1116 inch, but never over 1/8 inch.
MOUNTING GRINDING WHEELS ON SPINDLES
Use the following
procedure when grinding
wheels are to be
mounted on the spindle.
Inspect the wheel for
flaws and make the
wheel, flanges and
spindle so that the clamping pressure will be evenly
Check the speed of the spindle to make sure that it
is not running too fast for the type and size of wheel.
Make sure the hole in the wheel bushing is the right
size for the spindle. (neither too small nor too large.)
Use flanges that are recessed and large enough
to clamp the wheel well toward its circumferences.
Tighten the spindle end nuts just enough to keep the
wheel from moving out of position between the
Before turning on power, make sure that the wheel
runs true and will strike no obstructions
GRINDING WHEEL "RING" TEST
New grinding wheels should be promptly unpacked upon
receipt and given the "ring" test for damage suffered.
Also, give this test immediately before mounting either a
new or used wheel on the spindle, especially if the wheel
has been in storage for a long time.
The" ring " test readily discloses defects in grinding
wheels, including flaws and cracks, even though most
defects are invisible to the naked eye.
Make the test by suspending the wheel free and clear
and tapping it gently with a light wooden implement. A
wooden screwdriver handle would be appropriate for a
light wheel. A wooden mallet would be good for a heavy
Sound and undamaged wheels will emit a clear metallic
tone when tapped. If the wheel is defective there will be
Wheels bonded with organic material do not emit the
same clear metallic sound as do verified and silicate
Any wheel should be dry and free of sawdust when the
"ring" test is given; otherwise the sound will be
Listed below are several suggestions that, if followed,
will eliminate machine abuse and provide maximum
protection for the operator:
Wear safety glasses at all times when working
adjusting guards and tool rest. Do not remove
the glasses until the job is completed and the
machine shut off.
52-14 Change 3