Replacing a hacksaw blade is so easy there is no reason not to have a sharp blade at all times. A hacksaw is a general-use cutting tool which means you have to keep the blade in good working order for regular use.
Step 1 - Remove Blade
The first thing you need to do is loosen and remove the current blade. Do this by releasing the small clamps or screws at either end of the blade. There will be one near the handle and one near the end of the saw frame. Be careful and make sure you do not cut a finger on the blade while removing it. The blade should be easy to pull free once the clamps are released.
Step 2 - Maintenance
Before adding the new blade, give the hacksaw frame a quick wipe with a clean cloth lightly sprayed with penetrating oil. This will remove debris and grime and help keep your hacksaw in pristine condition.
Step 3 - Install New Blade
Carefully take your new blade and slot it into position within the frame. It should click onto two pegs on either clamp. Gently tighten the screw or clamps and the blade has been replaced. Tighten these a little more if you want extra tension across the surface of the blade.