Depth Of Cut; Direction Of Feed And Thrust; Routing - Craftsman 315.17504 Owner's Manual

DEPTH OF CUT
As previously mentioned, the depth of cut is important
because it affects the rate of feed which, in turn, affects the
quality of a cut (and, also, the possibility of damage to your
router motor and bit). A deep cut requires a slower feed than
a shallow one, and a too deep cut will cause you to slow the
feed so much that the bit is no longer cutting, it is scraping,
instead.
Making a deep cut is never advisable. The smaller bits --
especially those only 1/16 inch in diameter -- are easily
broken off when subjected to too much side thrust. A large
enough bit may not be broken off, but if the cut is too deep a
rough cut will result--and it may be very difficult to guide and
control the bit as desired. For these reasons, we recommend
that you do not exceed 1/8 inch depth of cut in a single pass,
regardless of the bit size or the softness or condition of the
workpiece. See Figure 12.
To make deeper cuts it is therefore necessary to make as
many successive passes as required, lowering the bit 1/8
inch for each new pass. Ir_.order to save time, do all the
cutting necessary at one depth setting, before lowering the
bit for the next pass. This will also assure a uniform depth
when the final pass is completed. See Figure 13.
DIRECTION OF FEED AND THRUST
The router motor and bit revolve in a clockwise direction. This
gives the tool a slight tendency to twist (in your hands) in a
counterclockwise direction, especially when the motor is
starting up.
Because of the extremely high speed of bit rotation during a
"proper feeding" operation, there is very little kickback to
contend with under normal conditions. However, should the
bit strike a knot, hard grain, foreign object, etc. that would
affect the normal progress of the cutting action, there will be
a slight kickback-- sufficient to spoil the trueness of you r cut
if you are not prepared. Such a kickback is always in the
direction opposite to the direction of bit rotation.
To guard against such a kickback, plan your set-up and
direction of feed so that you will always be thrusting the tool
-- to hold it against whatever you are using to guide the cut
-- in the same direction that the leading edge of the bit is
moving. In short, the thrust should be in a direction that keeps
the sharp edges of the bit continuously biting straight into
new (uncut) wood.
DEPTH
OF CUT
---_, Iq_ WIDTH
r:l-°,cu,
Fig, 12
2ND.
PASS
1ST.
PASS 2ND. PASS
THRUST'J FEED
GUIDE INSIDE
la
ROUTING '_'
Fig. 14
=d
Whenever you are routing a groove, your travel should be in
a direction that places whatever guide you are using at the
right-hand side. In short, when the guide is positioned as
shown in the first part of Figure 14, tool travel should be left
to right and counterclockwise around curves. When the
guide is positioned as shown in the second part of Figure 14
tool travel should be right to left and clockwise around
curves. If there is a choice, the first set-up is generally the
easiest to use. In either case, the sideways thrust you use is
against the guide.
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