Black & Decker 7990 - Manual (Page 2)

5” BENCH GRINDER
TTACHING EYE SHIELDS
The two Eye Shields are made of clear, shatterproof plastic, and
are attached to the top of each wheel guard as shown in Figure
1.
First, slide the sheet metal nut “A” over the tang “B” in
the eye shield. Slide tang under top of wheel guard and fasten
shield in place with screw.
ATTACHING TOOL RESTS
The two Tool Rests are not interchangeable •—■ one fits the left
side of the grinder and one the right side. Be careful to assemble
parts exactly as shown in Figure 1, and note that the star iock-
.__washer-gaes-between.the wheel guard and the. inside^-of the-Tool
Rest. Tighten the wing nut firmly with a clearance of 1/16"
between the grinding v^heel and the Tool Rest-—see Figure 2.
Tool Rests are adjustable for wheel wear. Keep them adjusted so
that a clearance of 1/16" is continually maintained between the
wheel and the Tool Rest as the wheel wears. This clearance is
very important as it will prevent any loose piece of significant
size from^ jamming between the v/heel and the Tool Rest. Such
jamming could fracture the wheel, break the Tool Rest, or both.
FIGURE 2
BENCH MOUNTING
Mounting the grinder on a bench is strongly recommended in
order to prevent movement of the grinder when pressure is
applied against a wheel. First, slide Rubber Feet on both sides
and In the middle of the grinder base as indicated in Figure 4.
Then drill three holes for wood screws or bolts In the
bench as shown in Figure 3. Use wood screws or bolts as
shown In Figure 4, and tighten down only enough to partially
compress rubber feet (about 1/16"). The rubber feet will not
be effective in absorbing virbratlon if fully compressed. When
using bolts, a second nut is required to lock against the
first nut and keep grinder from loosening during operation.
Never operate the grinder without the rubber feet attached to
its base.
OPERATION INSTRUCTIONS .........
'When you face the Bench Grinder, the wheel on your left is a
5" Grinding ¥/hee!. This v/heel is used for metal grinding and
sharpening operations.
The wheel to your right is a 4" Sanding/Polishing Wheel,* This
wheel IS used for sanding wood and plastic, removing paint and
rust, polishing metal, honing cutting tools, smoothing rough
edges on glass, and de-burring pipe, sheet metal, etc.
To operate the Bench Grinder, put on safety glasses or other
eye protection and hold the work firmly. Rest the work on the
tool rest and feed it slowly into the wheel at the desired grinding
angle. Treat the wheel with respect ... do not jam the work
into the wheel or use unnecessary pressure.
Grind only on the face of the grinding wheel, unless you have a
special wheel specifically made to permit grinding on the side of
the wheel.
= Some 5"
Wheels.
Bench Grinders are equipped with two 5" Grinding
WIRE BRUSHING INSTRUCTIONS
Wire Brushing quickly removes rust, scale or old paint. ALWAYS
wear safety glasses or other eye protection when using wire
wheels as pieces of wire may break off and be thrown from the
rotating brush. Handle Wire Wheel Brushes carefully with gloves
or rags to avoid punctyring the skin.
BUFFING INSTRUCTIONS
Use Cotton Buffing Wheels, normally with stick'buffing com­
pound applied to the face of the wheel (usually about %" wide).
Wear safety goggles for protection against particles of compound
thrown off by the wheel. Remove the tool rest if* it interferes
with the buffing operation. Do not jam work into wheel. Hold
work firmly.
CmMGiMG WHEELS
UNPLUG POWER CORD AND BE SURE THAT SWITCH STAYS
IN THE “OFF” POSITION.
1. Remove End Cover—see Figure 5. Remove the screw in the
back of the wheel guard. Using a screwdriver if necessary,
pry the end cover outward from the wheel in the direction
of arrow #1. Slide the cover backward (arrow #2) out of
the grooves in the front of the wheel guard.
2. See Figure 6. Remove clamp nut “A” by turning it in the
direction the wheel normally rotates. (The nut “A” shown
is black and has a left-hand thread. The silver-colored nut
at the other end of the grinder has a right-hand thread).
Use a screwdriver in the end slot “D” to hold spindle when
removing nuts.
3. Remove Outer Clamp Washer “B” (silver colored with small
hole), Wheel, and Inner Clamp Washer “C” (black with large
hole). Inspect washers. If they are burred or not perfectly
flat, repair or replace them.
CHANGING WHEELS (Continued)
4.
5.
6.
7.
8 .
Each Grinding Wheel purchased should be equipped with a
blotter fastened to each side of the wheel. Blotters must
always be used between the wheel and the inner and outer
clamp washers. Contact surfaces of wheels, blotters and
washers must be clean and flat.
Always use the exact type of clamp washers that are supplied
with your tool. Never substitute flat or odd sized washers.
Replace them in the exact order and position shown in
Figure 6. Always place hollow sides of washers against
wheel.
Only tighten arbor nut sufficiently to drive the wheel without
slippage. Hold spindle with screwdriver in end slot “D”.
Do not overtighten.
•
Be sure to replace end covers (see Figure 7). Slide cover in
direction of arrow “A” into upper and lower grooves in wheel
guard. Push cover toward wheel (arrow “B”) with threaded
tab inside wheel guard. Replace screw.
After installing replacement wheel, put on safety goggles and
stand to the side of the grinder, turn switch “ON” and allow
wheel to revolve freely for one minute before beginning to
grind.
If a new wheel has excess vibration, loosen nut and rotate
wheel about Vz turn on shaft. Retighten nut.
FIGURE 7
TAB
INSIDE
CASTING
LUBRICATION
Bench grinder spindles are mounted on lubricant impregnated
bearings. Nc periodic lubrication is required.
ACCESSORIES
GRINDING WHEELS (5" Diam. x V 2 " Face x Vz" Arbor Hole).
Manufactured by the nation's leading abrasive manufacturers to
stringent quality specifications.
Cat. No. 79-555 Coarse — 36 Grit
Cat. No. 79-556 Medium — 60 Grit
SANDING/POLISHING WHEEL (4" Diam. x face x 1 / 2 " hole)
Cat. No. 79-255 For sanding, polishing, honing, etc.
WIRE WHEEL BRUSHES (V 2 " Arbor Hole).
Each wire tuft is locked independently, giving a dense, even
brushing surface, and less danger of loose wires.
Cat. No. 70-142 4", Coarse Wire
Cat. No. 70-143 4", Fine Wire
COTTON BUFF:
For general purpose buffing and polishing.
Cat. No. U-1322
4" Diam. x %" FacP v 1 / 2 " Arbor Hole.
NOTE; The above accessories are recommended for use with
your Bench Grinder. CAUTION: The use of any other accessory
or attachment might be hazardous.