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BURR KING MFG. CO., INC.
1220 TAMARA LANE
WARSAW, MO 65355
WWW.BURRKING.COM
(660) 438-8998
s
(800) 621-2748
FAX (660) 438-8991
April 2000
Instruction for aligning the idler wheels on model 760 belt grinders
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 miss aligned. 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. In
example, the model 760 prior to mid 1999 was shipped with wheels that are 1.75 inches wide. Currently,
model 760 machines are shipped with wheels that are 2.0 inches wide. The 1.5 and 2.0 inch wheels may
be interchanged and/or mixed; however, if they are mixed their widths must be taking into account when
performing this alignment. The model 760 contact wheel may be 0.5, 1.5, or 2.0 inches wide. Likewise
the width of the contact wheel must be taken into account when performing this alignment.
Never perform maintenance or adjustments as described below on your model 760 without
first disconnecting the machine from its source of electric power. Failure to observe this
warning may lead to serious personal injury.
Procedure: (disconnect electric power and remove the abrasive belt)
1. Install the rear idler such that its inside-bearing surface is approximately 0.06 inches out from the
wheel support P/N 735. Secure the wheel with locking set screw P/N 25.
2. Install the upper wheel such that its inner bearing surface is approximately 0.06 inches out from its
bearing support P/N 714. Secure the wheel with locking set screw P/N 25.
3. Loosen the retaining nut P/N 22 that locks the upper idler wheel adjusting screw P/N 721. Using
screw P/N 721 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 of P/N 721.
4. Project a line from the upper idler outside rim to the outside rim of the rear idler. Adjust the tracking
control P/N 711 until the wheels are exactly planar. That is their radial centers are aligned.
5. 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.
6. Tighten the locking nut on P/N 721.
7. 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.
8. Apply electric power to the machine and verify that the tracking control P/N 711 will sweep the belt
across the face of the contact wheel. At least ½ inch adjustment in both directions from center should
be possible.
