Craftsman 21914 - 12 in. Drill Press Operator's Manual page 22

CHANGINGSPEEDS
See Figure 25.
The spindle speed is determined by the location of the
belt on the pulleys inside the head assembly. The speed
chart located on the cover inside the head assembly
shows the recommended speed and pulley configuration
for each drilling operation.
To change the pulley configuration:
[] Lift head assembly cover from front to open.
[] Loosen the tension knob.
[] Remove the drive belt.
[] Reposition the belt according to the speed chart.
[] Retighten the tension knob.
SPINDLE DRIVE MOTOR
PULLEY BELT PULLEY
TENSION
KNOB
Fig. 25
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