Craftsman 320.17541 - Manual (Page 28)

OPERATION cbrit.
RATE OF FEED (Figs. 17 and 17a)
The proper rate of feed depends on several factors: the hardness and moisture content
of the workpiece, the depth of cut, and the cutting diameter of the bit. When you are
cutting shallow grooves in soft woods such as pine, you may use a faster rate of feed.
When making deep cuts in hardwoods such as oak, you should use a slower rate of feed.
FEEDING TOO FAST (Fig. 17)
Clean and smooth finished cuts can only
be achieved when the cutter bit is rotating
at a relatively high speed, taking very small
bites, producing tiny, dean cut chips.
Forcing the feed of the cutter bit forward too
fast slows the RPM of the cutter bit, and the bit
takes bigger bites as it rotates. Bigger bites
mean bigger chips and a rough finish.
This forcing action can also cause the
router motor to overheat.
Under extreme force-feeding conditions, the RPMs can become so slow and the bites
become so large that chips become partially cut off, causing splintering and gouging
of the workpiece.
The router will make clean, smooth cuts if allowed to run freely without the overload of
forced feeding. You can detect forced feeding by the sound of the motor. Its usual
high-pitched whine will sound lower and stronger as it loses speed. Holding the router
against the workpiece will also be strained and harder to do.
Fig. 17a
Bit
Shank
FEEDING TOO SLOW (Fig. 17a)
When you feed the cutter bit too slowly,
the rotating cutter bit does not cut into
new wood fast enough to take a bite,
instead, it scrapes away sawdust-like
particles. This scraping produces heat,
which can glaze, burn and mar the cut
in the workpiece and, in extreme cases,
overheat the cutter bit.
When the cutter bit is scraping instead
of cutting, the router is more difficult to
control as you feed it.
With almost no load on the motor, the cutter bit has a tendency to bounce off the sides of
the cut in the workpiece, producing a cut with a rippled finish instead of clean straight sides.
TOO SLOW
Cutter
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