FORCE FEEDING
The router is an extremely high-speed tool (35,000 - 40,000
RPM), and will make clean, smooth cuts if allowed to run
freely without the overload of a forced feed. Three things
that cause force feeding are cutter size, depth of cut, and
workpiece characteristics. The larger the cutter or the
deeper the cut, the more slowly the router should be
moved forward. For harder materials, the operation must
be slowed still more.
Clean, smooth milling can be done only when the cutter is
revolving at a relatively high speed and is taking very small
bites to produce tiny, cleanly-severed chips. If the router is
forced to move forward too fast, the speed of the cutter
becomes slower than normal in relation to its forward
movement. As a result, the cutter must take bigger bites as
it revolves. Bigger bites mean bigger chips and a rougher
finish. Bigger chips also require more power, which could
result in overloading the motor.
Under extreme force-feeding conditions, the relative speed
of the cutter can become so slow—and the bites it has to
take so large—that chips will be partially knocked off rather
than fully cut off. This may result in damage to your cutting
tool and gouging of the lower
receiver
.
OPERATION
DIRECTION OF FEED AND THRUST
See Figure 4
The router motor and cutter 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 starts.
Feed the router into the workpiece from left to right. When
fed from left to right, the rotation of the cutter pulls the router
against the workpiece. If fed in the opposite direction, the
rotation forces of the spinning cutter will tend to throw the
router away from the workpiece, causing kickback. This
could result in loss of control of the router.
Because of the extremely high speed of cutter rotation dur-
ing a proper feeding operation, there is very little kickback
to contend with under normal conditions. However, should
the cutter engage too much material, that would affect the
normal progress of the cutting action, and there could be a
slight kickback. Kickback could be sufficient to spoil the
finish of your lower and damage the cutting tool if you are
not prepared. Such a kickback is always in the direction
opposite the direction of cutter rotation.
To guard against 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 cutter is moving. The
thrust should be in a direction that keeps the sharp edges of
the cutter continuously biting into the aluminum.
PROPER RATE OF FEED
Professional results depend upon using the proper rate of
feed. The proper rate of feed is dependent upon:
•
The hardness of the workpiece
•
The depth of cut
•
The cutting diameter of the cutter
Choose a rate of feed that does not slow down the router
motor. Choose the rate at which the cutter advances
smoothly and surely to produce uniform chips. Vibration
and chatter and excess noise when milling signals force-
feeding. Force
feeding increases the strain on the motor
and results in loss of speed and degraded finish quality.
The smaller the depth of cut, the faster the rate of feed that
can be used. The rate of feed should be reduced when
milling corners where more material will engage the cutting
too
l
.
There is no fixed rule for rate of feed. Proper rate of feed is
learned through practice and use. Always start
out
with
shallow cuts and a slow feed rate until you find the proper
balance between speed and finish quality.
8
WARNING:
To reduce the risk of injury and property damage, you must read and
understand this operator’s manual before using the router. Always wear eye and hearing
protection when using the router. Always wear eye protection with side shields marked
to comply with ANSI Z87.1.
WARNING
:
Milling aluminum creates sharp chips. Never use
compressed air to blow the chips away. Using
compressed air will blow chips around which can
cause injury to eyes, skin, and lungs if inhaled.
Chips should be vacuumed or brushed away.
WARNING:
Always use a dust mask to prevent inhaling harmful
particles which can be released or created when
operating a router.
