A homeowner often keeps a hacksaw in his tool box. Hacksaws cut metal components such as bolts, pipes and solid metal pieces. A hacksaw has two parts: the frame and the blade. Hacksaw manufacturers make blades with different numbers of teeth per inch, or TPI. Generally, the thicker the piece you cut, the lower the number of teeth per inch you need. A rule of thumb is to keep between 6 and 12 teeth in contact with the piece you are cutting. A sharp new blade is essential for fast smooth cuts.
Loosen the wing nut near the hacksaw's handle. Loosen the nut by turning it counter-clockwise. Ensure the wing nut is loose enough so you can remove the old blade from the frame.
Remove the old blade from the frame. Remove the blade by lifting it off the blade retaining pins at each end of the frame.
Install a new blade onto the blade retaining pins. Ensure the blade's teeth point away from the handle.
Tighten the wing nut by rotating it clockwise until the blade is tight.
Make a test cut on a piece of scrap metal held in a vise. Tighten the wing nut further if the blade binds or flexes during the cut.