Hacksaws are hand tools designed to cut metal that is too thick or hard for snippers or cutters. Hacksaws consist of two main elements: a frame with a handle and a blade. Hacksaw blades are generally classified as either hardened or flexible, though variations in terms of coarseness, teeth pitch and length should also be taken into consideration when choosing the proper hacksaw for your task.
Hardened Blades - Hardened hacksaw blades are made of tempered high-grade tool steel. The steel is hardened throughout the entire blade, including the teeth and the backing. Sometimes referred to as all-hard blades, these blades maintain their sharpness and their teeth, but they can be brittle and more prone to breaking.
Flexible Blades - Flexible blades only contain hardened steel on the teeth of the blade. The backing of the blade is a flexible metal sheet. These blades are sometimes called bimetal blades. They are less brittle than all-hard blades and therefore less prone to snapping.
Additional Variations in Blade Type - Hacksaw blades of both hardened and flexible varieties are available in many forms. The blade pitch refers to the number of blade teeth per 25 millimeter; the more widely spaced the teeth, the coarser the blade. Coarse blades are appropriate for soft metals, while finer blades are better for sheets and harder metals. The set of the blade refers to the angle of the teeth and can be either an alternating set for softer metals or a wave set for harder metals. Blades also vary by length and typically range from 8-inch to 12-inch.