Hacksaw

Hacksaws have a tensioned frame that holds a fine toothed blade. They are designed to cut hard materials like metal, plastic, tile, and glass. A close quarter or mini hacksaw is a smaller version with an open frame that is made for cutting in hard to reach areas.

Power hacksaws are used to cut large sizes (sections) of metals such as steel. Cutting diameters of more than 10/15mm is very hard work with a normal hand held hacksaw. Therefore power hacksaws have been developed to carry out the difficult and time consuming work. The heavy ‘arm’ moves backwards and forwards, cutting on the backwards stroke.


Hacksaw	Close quarter or mini hacksaw	Power hacksaw

Blades

Hacksaw blades are replaceable and are 10” or 12” long.
They are available with fine, medium, or coarse teeth that range from 14 to 32 teeth per inch (tpi). A blade with 14 tpi is coarse whilst a blade with 32 tpi is very fine.
Hacksaw blades are available in a number of materials including (from soft to hardest) carbon steel, high speed steel, bimetal, and carbide grit.
Hacksaw blades are rated on the Rockwell hardness scale with a higher number indicating a harder blade.

Use

A blade should always be positioned with its teeth pointing away from the handle.

The general rule is that at least three teeth should extend across the surface of the material to be cut.

14 tpi: large sizes, aluminium and soft metals.
18 tpi for general use.
24 tpi for steel plate up to 6 mm
32 tpi for hollow sections and tubing

While harder blades can cut through tougher materials, they’re also more brittle and prone to shattering. Bimetal and carbide tipped blades solve this problem by combining a softer metal blade with hard teeth.

Carbon steel blades are economical and are used for cutting wood, plastic, aluminum, copper tubing and other easy to machine metals.
High speed steel blades are just about shatterproof and cut wood, plastic and most metals.
Bimetal blades provide the longest life with a hardened cutting edge that resists wear and heat. They can be used with wood, plastic, and most metals.
Carbide grit blades are used for hard to cut materials such as glass, stranded cable, hardened steel, and tile. They cut on both the push and pull strokes which make for much longer wear.

Safety

Concentration is very important.
The saw must always be held straight.

Power hacksaws are used to cut large sizes (sections) of metals such as steel. Cutting diameters of more than 10/15mm is very hard work with a normal hand held hacksaw. Therefore power hacksaws have been developed to carry out the difficult and time consuming work. The heavy ‘arm’ moves backwards and forwards, cutting on the backwards stroke.


	The metal to be cut is held in a machine vice which is an integral part of the base. Turning the handle tightens or loosens the vice. The vice is very powerful and locks the metal in position.

	When cutting is taking place, the metal and especially the blade heats up quickly. Coolant should be fed onto the blade, cooling it down and lubricating it as it cuts through the metal. Without the use of coolant the blade will over heat and break/snap. This can be dangerous as the blade can break with powerful force, shattering.