i. 10-inch adjustable jaw wrench
amount to be torn out and will increase the power
j. Additional tools for the power unit
accordingly.
12-5. A rip chisel tooth saw cuts across the center and
tears out the two corners. For this reason, the width of the
12. Caring for the Saw
cut or stroke does not materially affect the power required
12-1. Your job is not complete when you finish sawing
The two edges have to be torn free, regardless of how
the lumber. You must take care of the saw. It is
narrow the cut or stroke is, and this is what consumes the
impossible to place enough emphasis on taking care of the
power. Notice the chisel tooth shown in figure 51. The
saw. It can truthfully be said that it is the most important
corners of the tooth do the tearing. Therefore, the things
part of any type of machine which converts logs into
that lessen the tearing effect of the corners will affect the
lumber, whether it be a stationary or a portable sawmill.
power consumption immediately and cause a
If you do not take care of your saw, it can slash your
corresponding increase in the power used through each
production, ruin the accuracy of the dimensions if the
tooth. This can cause much trouble. Therefore, the
lumber, and leave you in the depths of despair.
condition of the corners of the teeth is of great
12-2. There is nothing on the sawmill that takes as
importance.
much abuse as the saw. For instance, should a log come
12-6. In addition, if one corner of the tooth becomes
loose from the dogs while this tremendous strain is on the
duller than the other, the one causing the greater
saw, it will very likely kink (bend) it, bringing a halt to
resistance will have a tendency to force the saw the
operations and resulting in loss of time and manpower.
opposite way, which will cause the side of the saw to rub
All saws vary considerably and require different methods
on the side of the log. If the saw rubs on the side of the
of handling. This is partly due to the hardness or
log, it will do one of two things: (1) If the log is moving
mildness (softness) of the steel from which they are made.
endways slowly, and if the saw is rotating as it rubs the
12-3. Teeth. A new saw will always run well for a
slowly moving log, it will generate heat in the saw which
few hours. It may make a rather rough cut, but it will
will cause the metal to expand. This, in turn, will cause
always run a few hours if the saw is tensioned for the
the saw to lose the stiffness required to run straight The
proper speed and the natural lead is properly set. These
further this condition is allowed to develop, the more
facts assure you that, if the teeth can be kept properly
difficult it becomes to remedy. (2) On the other hand, if
sharpened (like new teeth), the saw will continue to run
the log is passing the saw at a higher rate of speed, the
and cut in a true line. Therefore, when you find that it
saw will have a tendency to cool as it rubs against the log,
does not do this, the deviation usually indicates that the
because the inside of the
saw teeth have not been sharpened properly. It has been
proven that if an improperly sharpened saw is too long it
will lose the proper tension and may cause blisters to
develop on the saw blade. If this happens, you will have
to have a competent saw expert retension the saw by
hammering it. Hammering a saw is an art and should
under no circumstances be attempted by anyone with
limited experience. When your saw ceases to cut
properly, stop your operations and sharpen it.
12-4. Blade. Most of your sawing will be done with a
chisel tooth. So let's find out how a chisel tooth saw
works. Many saws used to cut wood lengthwise of the
grain are swedge-set chisel tooth saws. Many saws used
to cut crosswise of the grain are spring-set pointed tooth
saws. A spring-set cutoff saw cuts the sides free and tears
out the portion between the two edges that are cut free by
the sharp points. Therefore, as soon as the point become
dull and do not cut the edges free, further sawing is
difficult, and the saw is said to be dull. Sharpening the
points will correct this situation and you can resume your
work. Inasmuch as the center is torn out, any alight
increase in the kerf (cut or stroke) will increase the
Figure 51. Chisel tooth.
37
Previous Page
