Bosch 1873-6 Operating/Safety Instructions Manual page 10

BM 1609929H54 08-06
Start the tool before applying to work and let
the tool come to full speed before contacting
the workpiece. Lift the tool from the work
before releasing the switch. DO NOT turn the
MOTOR HOUSING RELEASE LEVER
(Model 1894-6 only)
Your tool is equipped with a motor housing
release lever that will allow you to rotate the
spindle in either direction 90˚. To use this
feature, pull release lever in direction of
arrow to release housing, and rotate housing
until it clicks into place.
SELECTING GRINDING WHEELS
Before using a grinding wheel,
! WARNING
be certain that its maximum
safe operating speed is not exceeded by the
nameplate speed of the grinder. Do not
exceed the recommended wheel diameter.
DISC GRINDING WHEELS
Grinding wheels should be carefully selected
in order to use the grinder most efficiently.
Wheels vary in type of abrasive, bond,
hardness, grit size and structure. The correct
type of wheel to use is determined by the job.
Use disc grinding wheels for fast grinding of
structural steel, heavy weld beads, steel
casting, stainless steel and other ferrous
metals.
SELECTING SANDING DISC
Sanding discs are made of extremely hard
and sharp aluminum oxide grits, phenol-resin
bonded to a sturdy fiber backing for fast
heavy-duty service and long life. The discs
vary as to size and spacing of the abrasive
grits. OPEN COAT (type H) — used for soft
materials and on paint or varnish. CLOSED
COAT (type K) —used for metal, hardwood,
stone, marble and other materials.
8/3/06 11:44 AM
Grinding Operations
Sanding Operations
Page 10
switch "ON" and "OFF" while the tool is
under load; this will greatly decrease the
switch life.
GRINDING TIPS
Efficient grinding is achieved by controlling
the pressure and keeping the angle between
wheel and workpiece at 10° to 15°. If the
wheel is flat, the tool is difficult to control. If
the angle is too steep, the pressure is
concentrated on a small area causing
burning to the work surface.
Excessive or sudden pres-
!
WARNING
sure on the wheel will slow
grinding action and put dangerous stresses
on the wheel.
When grinding with a new wheel be certain to
grind while pulling tool backwards until wheel
becomes rounded on its edge. New wheels
have sharp corners which tend to "bite" or cut
into workpiece when pushing forward.
Sanding discs range in grit from 16 (very
coarse) to 180 (very fine). To obtain best
results, select sanding discs carefully. Many
jobs require the use of several grit sizes and
at times both "open coat and closed coat"
discs are required to get the job done faster.
See chart for application examples.
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