OPERATION
WARNING:
Keep a firm grip on router with both hands at all times. Failure to do so could result in loss of control leading to possible serious injury.
TOO SLOW FEEDING (Continued)
In addition, it is more difficult to control a router when the bit is scraping instead of cutting. With practically no load on the motor the bit will be revolving at close to top RPM, and will have a much greater than normal tendency to bounce off the sides of the cut (especially, if the wood has a pronounced grain with hard and soft areas). As a result, the cut produced may have rippled, instead of straight sides. See Figure 9.
You can detect
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 in. (1.6 mm) 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 in. (3 mm) depth of cut in a single pass, regardless of the bit size or the softness or condition of the workpiece. See Figure 10.
To make deeper cuts it is therefore necessary to make as many successive passes as required, lowering the bit 1/8 in. (3 mm) for each new pass. In 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 11.
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 revs up (as at starting).
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
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Fig. 10
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Fig. 11
GUIDE OUTSIDE
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| Fig. 12 |
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 your 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 setup 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.
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