Unplug the drill press.
Turn the thumbscrews holding the pulley cover counterclockwise to loosen the pulley cover. Pull the pulley cover straight off the top of the drill press.
Loosen the motor tension by turning it counterclockwise with an adjustable wrench. Continue turning the tension bolt until the v-belt connecting the two pulleys sits loosely on the pulleys.
Read the belt location chart printed on the inside of the pulley cover to determine the RPMs achieved by setting the belt between the different sized pulleys. As a rule, setting the belt on the largest pulley sitting on the drill head shaft and the smallest pulley on the motor shaft will spin the drill bit slower. Connecting the belt to the largest motor shaft pulley and the smallest drill head pulley will cause the drill bit to spin faster.
Turn the tension bolt clockwise with the adjustable wrench to apply tension to the v-belt.
Set the pulley cover over the pulleys. Align the thumbscrews with the holes in the cover. Turn the thumbscrews clockwise to secure the pulley cover to the head of the drill press.
Plug in the drill press cord.