The Sears model jig saw is manufactured by Craftsman and sold under many different brand names. The jig saw is a portable version of a table scroll saw. The blades are thin and break or become dull over time. Changing the jig saw blade on a Sears model saw depends upon which locking mechanism the saw uses. Some have quick release levers, while others require rotating the round knurled collet, or collar, around the blade.
Unplug the Sears model jig saw power cord from the wall outlet. Lay the jig saw on its left side with the blade and the bottom of the tool pointing toward you.
Lift the release clamp on the side of the blade holder up towards the body of the jig saw with your thumb. Pull the blade out of the jig saw while holding the release clamp. Release the clamp once the blade is out of the saw. Newer models simply require you to turn the round collet around the blade counterclockwise and lift it toward the body of the saw.
Position a new jig saw blade with the hole on the one end pointing toward the saw and the teeth pointing toward the front of the saw.
Raise the release lever with your thumb and hold it in place or turn the round collet. Insert the jig saw blade fully into the blade holder. Slowly release the clamp or collet to lock the blade in place.