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Workpiece.Inspection
Some workpieces are not suitable for grinding
on a bench grinder. Before grinding, inspect all
workpieces for the following:
•
Hard Workpiece: Workpieces that are made
of stone, carbide, stainless steel, ceramics,
glass, or have hardened welds will wear out
most general-grade grinding wheels quickly.
If hard materials are to be ground, you must
install the correct type of grinding wheel.
•
Soft Workpiece: Workpieces that are made
of aluminum, brass, lead, and other non-
ferrous metals will load up in the grinding
wheel and render the abrasive useless.
Grinding wood, plastics, rubber, fiberglass,
or other soft materials can also cause the
same problem and lead to the wheel over-
heating and possibly bursting during use if
ignored. To restore a loaded grinding wheel
surface, redress with a dressing tool.
•
Flexible/Unstable Workpiece: Grinding on
the side or the ends of cable, chain, or round
workpieces creates the hazard of workpiece
twist or grab, leading to entanglement with
the wheel or shaft. This hazard must be
avoided.
•
Loose Parts: Make sure that the workpiece
is free of any parts like springs, pins, balls,
or other components that may loosen or dis-
lodge during grinding, and hit the operator.
•
Strength: Make sure that the workpiece is
strong enough to be ground. Should it break,
the broken piece may dig into the wheel and
cause kickback or severe injury.
Electrical system is not waterproof. DO NOT
use grinder with liquid cooling system for
wet grinding. Ignoring warning can lead to
electrocution or machine damage.
Model W1839 & W1840 (For Machines Mfd. Since 3/16)
Wheel.Selection
The Model W1839 only accepts Type-1 wheels
with a
⁄
" bore. The W1840 only accepts Type-1
1
2
wheels with a
⁄
5
Aluminum oxide and silicon carbide wheels are
marked in a somewhat uniform manner by all
the major manufacturers. Understanding these
markings will help you understand the capa-
bilities of various wheels. Always refer to the
manufacturer's grinding recommendations when
selecting a wheel for your project.
The basic format for wheel numbering is:
Abrasive
Prefix
Type
1
A
The Prefix is the manufacturer's designation for
a particular wheel type (e.g. Type-1 wheels).
The most common Abrasive Types used are A
for Aluminum Oxide, C for Silicon Carbide, and
occasionally SG for Seeded Gel.
The Grit Size is a number that refers to the
size of the abrasive grain in the wheel. The
lower the number, the coarser the wheel. Ten
is a very coarse wheel for roughing, and 220 is
usually the upper range for fine finish work.
Grade is an indication of the hardness of the
wheel—"A" being the softest and "Z" being the
hardest.
Bond Type refers to the type of bonding
material used to hold the abrasive material.
Most general purpose wheels will have a "V"
indicating Vitrified Clay is used. Vitrified Clay
provides high strength and good porosity. The
other common bond type is "B" for resin where
synthetic resins are used. These are used to
grind cemented carbide and ceramic materials.
Note: There may be other numbers inserted
that have meaning for a particular type of
wheel. Refer to the manufacturer's technical
data for a complete explanation.
-20-
" bore.
8
Grit Size
Grade
60
L
Bond
Type
V
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