Skil 9290 - Manual (Page 9)

SELECTING GRINDING WHEELS
Before using a grinding
wheel, 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.
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-
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.
-9-
! WARNING
Grinding Operations
Hold the tool with both
hands while starting the tool,
since torque from the motor can cause the
tool to twist.
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
switch “ON” and “OFF” while the tool is
under load; this will greatly decrease the
switch life.
! WARNING
! WARNING
Sanding Operations
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.
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.
SANDING TIPS
For best results, tilt the Disc Sander at a 10°
to 15° angle while sanding so that only about
1" of the surface around the edge of the disc
contacts the work.
Operation: Refinishing painted wood or metal surfaces.
REMARKS GRIT
To remove paint and to smooth Coarse
surface irregularities. 16-24-30
To smooth Medium
the rough sanding. 36-50-80
To remove scratches left by Fine
previous discs. 100-120
To smooth surfaces for painting, Very Fine
polishing or waxing. 150-180
SM 2610947883 06-07 6/5/07 10:19 AM Page 9