A hacksaw is a manual saw that consists of a metal frame for securing a narrow, toothed blade and can be used for cutting wood, metal, plastic and other materials. Hacksaws are used in a broad array of applications ranging from plumbing to butchering. Although hacksaws are relatively safe compared to electric or gas-powered saws, precautions are still necessary to ensure safety and proper cutting.
Blade Type - Different hacksaw blades are available for various materials and material widths. The appropriate blade should be used to keep the saw from getting caught up in the material, which can cause jolting, unsafe sawing motions and irregular cuts. Blades with a greater ratio of teeth per inch (TPI), such as 10 or higher TPI blades, should be used for cutting thin materials that are 1-inch thick or less. Blades with a medium, 6 to 8 TPI ratio should be used for thicknesses between 1 inch and 4 inches. Blades with a low, 4 to 6 TPI ratio should be used for thicknesses greater that 4 inches. Use a carbon steel blade for cutting metals such as copper and aluminum and a carbide blade for cutting cast iron, ceramic, masonry or plastic. Use a spiral blade to cut notches and circles.
Blade Placement - The blade is secured in the hacksaw with the angle of the teeth facing forward–moving away from the handle. This allows you to cut the wood on the strokes that move away from you. Make sure that the nuts that hold the blade in place are tight so that the blade will not come loose, dislodged or jammed in the material being cut.
Securing the Material - Whether you are cutting flat material or pipes, the material should be secured on a worktable with vice grips or clamps. Securing the material will prevent it from shifting and causing dangerous jams and jolts of the hacksaw.
Handling the Hacksaw - A hacksaw user should hold the handle of the hacksaw firmly, like you would hold the handle of a pistol–with your fist wrapped around the handle and your forefinger pointing forward. The forefinger pointing forward and placed securely against the side of the hacksaw frame provides extra stability. The other hand can optionally be place on the front of the hacksaw blade to provide even more stability as well as to input more strength into the sawing motions. Push down on the saw for cutting only on forward strokes. Use strokes that are long, matching the majority of the blade length, and do not rush or use inconsistent or short and choppy strokes.