Sears 315.17504, 315.17505, 315.17506 Depth of CUT, Direction of Feed and Thrust, Routing, Pass

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

2ND.

PASS

la

ROUTING

DEPTH ---_,Iq_ WIDTH

OF CUT r:l-°,cu,

Fig, 12

1ST.

PASS 2ND. PASS

THRUST'J	FEED
GUIDE INSIDE	Fig. 14
	=d
'_'

--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.

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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