The Sears Craftsman reciprocating saw is a useful tool for any number of household chores. A dull blade might need changing or replacing sooner than expected.
Turn off and unplug the saw from the power source.
Remove the Allen wrench from the saw's holder. It is located on the underside of the handle by the cord.
Insert the Allen wrench into the hole on the side of the saw body toward the front, where you can first see the blade sticking out. Once inserted, there will be a blade clamp screw located on the blade clamp--insert the Allen wrench into the screw. If you can't see the screw, or are continually missing it, look into the front of the saw, down the length of the blade, and you will be able to see the clamp and screw through the front opening.
Loosen the blade clamp screw with the Allen wrench. Make sure you don't fully remove the screw--it can be difficult to put back in. Only unscrew it about five to eight complete turns, or about halfway up the screw. This will loosen the clamp, but not disassemble it.
Slide the blade out from the clamp. The blade, if installed correctly, will have a hole in it that rests around a notch in the blade clamp. This is just for security. Wiggle the blade a little if the notch is catching and pull gently. The blade will slide right out.