Utility knives are used to cut a variety of materials with a razor-sharp blade. When the two-sided blade becomes dull, it is removed from the body of the knife and either discarded or turned around and reinserted. Utility knives have either a rigid or a folding body. Body type is a key factor in changing the blade. Although both types can have a quick-change feature, you will find that it is usually simpler and faster to change the blade on rigid-body knives.
Locate the screw positioned near the center of the utility knife body.
Turn the screw counterclockwise with a flat-head screwdriver until the screw can be pulled from the knife.
Pull the back end of the utility knife body up and away from the blade end of the knife to separate the two halves of the body.
Tilt the cutting edge of the blade up and pull the blade from the sliding mechanism.
Inspect the ends of the blade. If one end of the blade is sharp, set the blade in the sliding mechanism with the sharp end of the blade facing the front of the utility knife. If both edges are dull, set a new blade in the sliding mechanism.
Set the two halves of the utility knife together, push the top half forward to align the screw holes, place the screw into the aligned holes and tighten the screw with a flat-head screwdriver.
Extend the blade of the rigid utility knife or open the folding utility knife.
Locate the lever or push button near the blade marked "Release."
Pull the blade away from the utility knife body while depressing the push button, or pull up on the back of the lever.
Inspect both ends of the blade. If one end is sharp, slide the dull end into the utility knife or slide one end of the new blade into the knife. If your utility knife has a lever release, hold the lever up until the blade seats in the knife body.