Oregon 760 Mode D'emploi page 10

Operation
Aligning Idler Wheels
When idler wheels are removed and/or replaced they must
be installed such that they are in proper alignment. Failure
to properly align the idler wheels will result in premature
failure of the wheels. Premature failure will be evidenced
by outer diameters being excessively worn such that the
wheels lose their factory crown, wear to a truncated form,
or become out of balance. Misalignment results in wear
that is analogous to front tire wear when the front steering
mechanism of an automobile is misaligned. The upper
idler equates to the front wheels of the car. If either idler
wheel is misaligned to each other or to the contact wheel,
excessive and irregular wear will occur.
The upper and rear idler wheels must operate in the same
plane. This means that when they are correctly aligned a
plane passing through the radial center of the upper wheel
will exactly pass through the radial center of the rear
wheel. Machines are shipped from the factory with wheels
of the same width. Currently, model 760 machines are
shipped with wheels that are 1.5 inches wide.
1. Disconnect electric power and remove the abrasive belt.
2. Install the rear idler such that its inside bearing
surface is approximately 0.06 inches out
from the wheel support. Secure the wheel
with locking set screw. (Figure 11)
3. Install the upper wheel such that its inner
bearing surface is approximately 0.06 inches
out from its bearing support. Secure the
wheel with locking set screw. (Figure 12)
4. Loosen the retaining nut that locks the upper idler
wheel adjusting screw. (Figure 13) Using screw
WARNING:
Never perform maintenance or
adjustments on your model 760 without first
disconnecting the machine from its source of
electric power.
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adjust the upper idler wheel until a straight line
representing the plane passing through the center
of the upper idler exactly passes through the
center of the contact wheel. This line represents
the center of belt travel. Note: make certain that
the bearing support is against the screw end.
5. Project a line from the upper idler outside rim to
the outside rim of the rear idler. Adjust the tracking
adjustment knob until the wheels are exactly
planar. That is, their radial centers are aligned.
6. Repeat step 3 and 4 until both conditions are satisfied.
That is, the upper and rear idlers are aligned to each
other and both wheels are aligned to the contact wheel.
7. Tighten the locking nut on the upper
idler wheel adjusting screw.
8. Install a new abrasive belt. Roll the belt manually
to assure that it will maintain coarse tracking. If
the belt does not track manually, repeat the prior
steps until it does. If after repeating these steps the
belt still will not track, the machine requires other
maintenance and/or one or both idler wheels require
replacing. The wheels should be replaced in pairs.
9. Apply electric power to the machine and verify
that the tracking adjustment knob (Item 8,
pg. 5) will sweep the belt across the face of
the contact wheel. At least ½-inch adjustment in
both directions from center should be possible.
Failure to observe this warning may lead to serious
personal injury.
1
Figure 11 Figure 12
Locking Set Screw,
1
Rear Idler Wheel
4
Upper Wheel
2
Locking Set Screw,
3
Upper Idler Wheel
5
Retaining Nut,
4
Upper Idler Wheel
Figure 13 5/32" Allen Wrench
5
3
2