Toro GR 105 Fundamentals page 23

Fundamentals of Reel Mowers
TORO® Service Training
This slide illustrates Single Blade Grinding
(which is also know as "Relief Grinding" or
"Back Grinding").
Toro recommends a 30 degree relief angle on
each reel blade. The angle itself is not critical.
You can put as little or as much angle on the
blade as you think is proper. A larger angle will
take off more steel and the reel may have to
be replaced sooner. With a smaller angle, you
may have to grind the reel more often to
maintain a relief.
It is a good idea to follow a blade grinding
sequence during the single blade grinding
process so that the reel ends up as close to a
cylinder shape as possible. This will reduce the
amount of backlapping needed after grinding
is completed. The numbers shown in the
illustration indicate one example of the
sequence that may be used. Remember that a
final grind in a spin grinder, and/or some
backlapping will get the reel into a true
cylindrical shape.
It will normally take several passes across
each reel blade to renew the sharp edge and
remove the taper from the reel. This example
may have required 4 or 5 passes and then was
completed with a backlapping job to create the
land area. NOTE: It is acceptable practice to
grind in both directions across the blades. The
goal is approximately a 30 degree back angle
and a land area.
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