Metal Drilling; Chuck Removal - Craftsman 315.116890 Operator's Manual

[] Whendrilling through holes, p lacea blockofwood
behind the workpiece t o prevent r agged or splintered
edgesonthe backsideofthehole.
METAL DRILLING
For maximum performance, use high speed steel bits for
metal or steel drilling.
[] Begin drilling at a very low speed to prevent the bit
from slipping off the starting point.
[] Maintain a speed and pressure which allows cutting
without overheating the bit. Applying too much pres-
sure will:
• Overheat the drill;
Wear the bearings;
Bend or burn bits; and
Produce off-center or irregular-shaped holes.
[] When drilling large holes in metal, start with a small bit,
then finish with a larger bit. Also, lubricate the bit with
oil to improve drilling action and increase bit life.
CHUCK REMOVAL
See Figures 10- 12,
The chuck may be removed and replaced by a new one.
[] Lock the switch trigger by placing the direction of rota-
tion selector in center position.
[] Insert a 5/16 in. or larger hex key into the chuck of the
drill and tighten the chuck jaws securely.
[] Tap the hex key sharply with a mallet in a clockwise
direction. This will loosen the screw in the chuck for
easy removal.
[] Open the chuck jaws and remove the hex key.
[] Using a screwdriver, remove the chuck screw by turn-
ing it in a clockwise direction.
NOTE: The chuck screw has left hand threads.
[]
Insert the hex key into the chuck and tighten the chuck
jaws securely. Tap sharply with a mallet in a counter-
clockwise direction. This will loosen the chuck on the
spindle. It can now be unscrewed by hand.
TO RETIGHTEN A LOOSE CHUCK
The chuck may become loose on the spindle and develop a
wobble. Also, the chuck screw may become loose, causing
the chuck jaws to bind and prevent them from closing.
To tighten:
[] Lock the switch trigger by placing the direction of rota-
tion selector in the center position.
[] Open the chuck jaws.
[] Insert the hex key into the chuck and tighten the chuck
jaws securely. Tap the hex key sharply with a mallet in
a clockwise direction. This will tighten the chuck on the
spindle.
[] Open the chuck jaws and remove the hex key.
[] Using a screwdriver, tighten the chuck screw by turn-
ing in a counterclockwise direction.
MALLET
CHUCKJAWS
HEX KEY
KEYLESS
CHUCK
Fig. 10
SCREWDRIVER
13
Fig. 11
Fig. 2