How to cut metal with a hacksaw

(Last modified: March 21st, 2019)

Hacksaws are a hand tool that is a very versatile addition to any workshop. Hacksaws work by simply moving the blade through the metal backwards and forwards in a regular ‘sawing’ action. The C shaped handles are relatively cheap to buy and the wide range of blades available enables a wide range of profile thickness and metal grades to be cut easily. The handles range from basic varieties that simply, yet securely, hold the hack saw blade in place through to professional varieties that have easy to use features such as; thumb dial tensioners in the handle to provide 150kg or 30,00 psi blade tension, adjustment to accommodate 250mm or 300mm blades, and  secondary blade positioning to enable 45° blade angle for flush cutting or 90° for general cutting.

metals4u hacksaw

Hacksaw blades are selected by choosing the correct tpi (teeth per inch) for the type of metal that needs to be cut. The higher the tpi, the more aggressive the cut. The teeth are configured to face towards one end of the blade and the blades can be mounted in the handle with the teeth facing forwards or backwards- the benefit of this is that the power of the ‘towards’ or ‘away’ stroke can be focussed to provide the user with the best cutting ergonomics. Many metal workers prefer to focus the main cutting stroke as the ‘away’ stroke as this provides a clearer view of the cut because the chips are moved forwards during operation.

Hacksaw blade tpi recommendations.

Tpi  (teeth per inch / 25mm of blade)

Suggested usage

14

Large profiles, aluminium, softer metals

18

General workshop projects

24

Steel plate up to 5/6mm thickness

32

Hollow sections and steel tubing

 

Tips for cutting metal using a hacksaw.

  • Always wear eye protection and gloves when cutting metal.
  • Select the correct blade for the project being undertaken and ensure it is securely inserted in the frame/ handle with the teeth facing either forwards or backwards depending on preference.
  • Check the blade is rigid, correctly aligned, and taut.
  • Clamp the workpiece or place it in a vice; if this is not possible as the metal is joined to another object, ensure the piece you are not wishing to remove will remain secure once the other piece has been cut off.
  • To begin the cut, make a series of one-way strokes against the direction of the teeth – this will create a narrow incision that the blade can sit in. Once the blade has gained purchase in a millimetre or so of the surface, the full forward and backwards sawing action will soon enable the cut off to be completed.
  • Try not to rush; a smooth, steady sawing action will provide the best cut and will reduce the likelihood of the blade overheating and breaking. A little machine oil or cutting fluid placed on the blade will reduce friction.