blade properly installed and tensioned, start the
raise the spring rod one step on the cam to reduce
blade motor for a final check.
the cutting force. Ideally, the average cutting
should produce a mixture of chips and curled chips.
3. OPERATION
Normally, a narrow work piece requires a light
A. CUTTING FORCE. When a new blade is in-
cutting force, and a wide work piece requires a
stalled on the machine, the cutting force should
medium to heavy cutting force. Tooth pitch must
always be reduced for the first five or six cuts. A
also be considered in determining cutting force. A
new blade, being sharp, will penetrate the work
coarse pitch blade on a narrow work piece will
much faster and may be damaged by tooth tips
chipping off or teeth stripping if the cutting force is
require much less cutting force that a fine pitch
not reduced. After the "break-in" period the
blade on the same work piece. To familiarize
cutting force may be increased to normal and, as
yourself with the saw blades, tooth pitch, cutting
the blade dulls, the cutting force may be increased
force and other related factors, read the ac-
more to maintain cutting speed. Eventually a point
companying Saw Blade Selection and Application
will be reached where either the blade will cut too
Manual.
slowly, or the force required to make it cut will be
so high that crooked cuts will result, dictating a
B. BLADE SPEED. One of the critical factors
new blade.
when cutting any type of material is the blade
speed. If a blade is run too fast for the material
The cutting force is adjusted by the step cam (Fig.
being cut, it will burn out long before it would have
6) that controls the tension on the counterbalance
worn out had it been run at the proper speed. When
spring. Lift the cutting head completely up. Then
the surface speed of any cutting tool is increased,
pull the spring rod out and rotate the cam up to the
the cutting edge will run hotter. At some point the
highest point for minimum cutting force, or the
critical temperature of the cutting tool will be
lowest point for maximum cutting force. In normal
exceeded and the tool will "soften" and sub-
use, position the spring rod in the second step down
sequently fail.
from the top. If you find the blades are producing
fine dust when cutting, increase the cutting force
To change the blade speed on 4-speed machines,
by iowering the rod one step. If the blade is being
open the belt guard and loosen the cap screw in the
overfed and is producing large heavy curled chips,
motor mount bracket (Fig. 7) so the motor will
Figure
Figure 3
Figure 4
Figure 6
21
