WORKMASTER GO-A8-PW Operator's Manual page 30

7. The ROTOR BLADES (27) are the most frequently replaced part since
they are subjected to a high degree of movement and friction. The
Blades are machined from a fibrous form of laminated phenolic. By
means of various treatments, Blades are stabilized so that they can
withstand a wide latitude of temperature, humidity, water and oil. They
are almost immune to warpage. All such characteristics are necessary to
the smooth cycling action of the Blades as they move in an out of the
Rotor slot. When the motor is running at regular speed, the Rotor Blades
will be in continuous and forceful contact with the cylinder wall. In this
powerful rotation each Rotor Blade can develop a thrust of over 6 pounds.
At such pressures, any foreign material caught between the outer edge of
the Blade, and cylinder wall can cause wear, scoring, and possible
breakage. An air filter can help remove such harmful material, and a
Lubricator will provide a thin oil film between the edge of the blade and
the cylinder wall. This provides a better pressure seal and lessens the
friction and wear.
If the Blade looses 20% or more of its width, or when, in the Rotor slot, it
is worn 3/16" or more below the OD of the Rotor, the Blades
must be replaced.
IMPORTANT
Blades narrowed from wear will eventually tilt at the edge of the Rotor
slot, and this will create a groove mark on the side of the Blade.
The groove mark will then deepen enough to cause the Blade to break or
bind on the edge of the slot. Blade breakage can cause severe damage to
the interior of the Cylinder. A Blade that binds on the edge of the slot will
stall the motor and keep it from moving.
Rotor Blades found to be within wear limits may be cleaned by a simple
lapping operation on each side and edge. Place a piece of 400 grit
waterproof sandpaper or fine Emery Cloth on a flat surface and lightly lap
each side of the Blade. This will clean the Blade, but will not remove
enough of the material to affect the overall performance of the Opener.
Width and height can be checked by comparing the
old blades with a new one.
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