Jet JBG-8A, Operating Instructions And Parts Manual

Page: 12 / 20

12
Maintenance
For safety, turn the switch to OFF and remove
plug from the power source outlet before
adjusting and maintaining the bench grinder. If
the power cord is worn, cut or damaged in any
way, have it replaced immediately.
Ring Test
Before replacing a grinding wheel, perform this
simple test on the replacement wheel:
1. Loop a piece of string through the grinding
wheel hole and suspend the wheel by
holding up the string.
2. Tap the wheel with a piece of scrap wood or
a wooden dowel.
A good wheel will "ring"; a defective wheel will
"thud". Discard any wheel that does not "ring".
An internal defect may not be apparent by visual
inspection alone. The ring test may uncover an
internal crack or void.
Care of Grinding Wheel
In normal use, grinding wheels may become
cracked, grooved, rounded at the edges,
chipped, out of true or loaded with foreign
material.
Cracked wheels should be replaced
IMMEDIATELY. While any of the other
conditions can be remedied with a dressing tool
(available at most hardware stores), new wheels
sometimes require dressing to make them
round.
Changing Wheels
If you must replace a wheel be sure to obtain
one with a safe rated speed at least as high as
the
NO LOAD RPM marked on the grinder's
nameplate. Refer to Table 2 to determine correct
dimensions for the replacement wheel.
Model
Wheel
Diameter
Maximum
Width
Center
Hole
JBG-6A 6" 3/4" 1/2"
JBG-8A
8" 1" 5/8"
JBG-10A 10" 1" 1"
Table 2
Your bench grinder will accept most polishing
and buffing wheels available at dealers and
hardware stores.
The use of any other
accessory is not recommended and may
result in serious injury!
To change a wheel (refer to Figure 4):
1. Disconnect grinder from the power source.
2. Loosen the spark guard (A) and tool rest (B)
(refer to the Adjustment section on page 11)
and move the spark guard and tool rest
away from the wheel.
3. Remove the guard cover using a Phillips or
flathead screwdriver.
4. Stabilize the wheel by holding the opposite
wheel firmly.
5. Unscrew the wheel nut (C) with a 1" wrench.
Note : Turn the locking nut on the right-hand
wheel counterclockwise to loosen. Turn the
locking nut on the left-hand wheel clockwise
to loosen.
6. Remove the outer flange (D) and wheel (E).
7. Clean flanges. Check the flanges to make
sure they are flat. Wheel flanges that are not
flat will cause the wheel to wobble.
8. Put the inner flange, wheel (E), outer flange
(D) and nut (C) on the shaft. Tighten the nut.
Do not over tighten. This may cause the
wheel to crack.
9. Replace the guard cover. Adjust the spark
guards and tool rests to a 1/16" clearance
from the wheel (see
Adjustments on
page 11 ) .
Figure 4