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RAZUR SHARP II
®
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Tips on Grinding
TIP: Do not overheat the tooth when grinding.
You do not need a thermometer to monitor heat, simply watch the surface of the cutter tooth. If the
tooth starts to discolor, you are getting it too hot. If you heat a tooth to the point that it turns blue,
you have ruined it. The blue color indicates the
temper of the steel in the cutter tooth has
changed.
Blue teeth occur when you are trying to grind too fast or when you are sharpening a "rocked"
or extremely dull chain. When you grind out extensive tooth damage, you will be inclined to
remove it faster than you should.
Try setting the grinder to remove only half of the damage on each tooth. When you have
ground all the cutters and are back to where you started, reset the feed stop and grind out the
rest of the damage on a second pass. By limiting the amount of material, you remove each
pass you may reduce heating potential. Another advantage of "double" grinding is that the teeth
get a chance to cool between the first and second grind.
Another cause of overheating is a dull grinding wheel. When the working comer of the stone
and the area around it begins to darken, it is getting dull. A dull stone does not grind well and
an inexperienced operator may be inclined to increase grinding pressure. To sharpen the
wheel, run the dressers over it until the dark spots are gone. This will clean the wheel and
expose fresh abrasive material.
TIP: Align the corner of the tooth with the working corner of
the stone.
The key to successful chisel chain grinding can be summed up with
this tip.
To obtain maximum "stay sharp" ability and cutting speed, these
two corners should be aligned perfectly. If you grind "high" or above
the corner, the chain will perform badly. It may look sharp to you but
it will act as if it is dull. If you grind too "low" below the corner, the
chain will cut but won't stay sharp very long.
If you look at a low chain closely, it will have a "bird's beak" edge on
the corner of the tooth. This edge has little support and will become
dull easily. In fact, even hitting a knot will dull a "low" ground chain.
The best rule to remember is:
Align the corners perfectly but if you need to allow for a little error:
Be a
little
low.
