Please note: How this is done may vary depending on the make and model. One method is shown below:
How is the blade attached?
A hacksaw has a removable blade mounted in a metal frame. Like all frame saws, the blade must be held taut in order to cut efficiently. The blade is held in place by two metal pins on either end of the frame. These pins hook onto two corresponding holes on either end of the hacksaw’s blade.
Removing the blade
Step 1 – Loosen wingnut
Turn the wingnut in an anti-clockwise direction. This controls the position of a metal bar at the end of the frame’s arm.
This bar holds one end of the blade. Turning the wingnut anti-clockwise pushes the bar forward, so that it’s no longer stretching the blade.
Step 2 – Unhook blade from pins
Once enough tension is released, you can remove the blade by unhooking it from the pins.
Installing the blade
Please note: Hacksaw blades come in two lengths: 250 or 300mm. Ensure you select the correct one for your hacksaw.
Step 1 – Loosen wingnut
Ensure the wingnut is loosened before hooking the blade onto the pins.
When installing a blade, ensure the teeth are on the outside of the frame, and are facing away from the handle. This is to ensure the hack saw cuts on the push stroke
Step 2 – Tighten wingnut
Once the blade is in place, turn the wing nut in a clockwise direction. This will cause the metal bar to move back, stretching the blade tightly in the frame.
How tight should the blade be?
If the blade is too loose, it will move about on the pins and could even fall off. A blade with too much movement will also make it hard to control the saw when working. However, stretch the blade too much and it could snap, potentially causing an injury.As a general rule, you should tighten the blade enough so that it does not move about on the pins, but can still flex very slightly in the centre.