Hand Saws Information
Hand saws are hand-held tools, either powered or manually-driven, that are designed to cut through softer materials. They accomplish cutting using a hard, serrated blade, or by using a wire with an abrasive edge. There are many different types of hand saws that vary based on how and what they cut.
When selecting hand saws, the most important consideration is the cutting type. Beyond this a number of important design parameters to consider are the number of teeth per inch (TPI), how it is driven (manually or power driven), and the saw length and size.
Saw types are designated based on how the saw cuts, which is the primary factor in deciding what type is suitable for a specific application.
Crosscut saws are handsaws for manually cutting wood across the grain. Each cutting tooth is angled to cut with one edge and push sawdust out with the other. Their blades contain 8 to 15 TPI.
Rip saws are designed for making cuts in wood parallel to the direction of the grain. The cutting edge of each tooth is flat and acts like a chisel to tear along the grain. Their blades contain 4 to 10 TPI.
Back saws are small handsaws useful for woodworking projects for cutting joints or grooves in wood. The blade is rectangular, 8 to 14 inches in length, with a metal-reinforced back edge to keep it from bending while cutting. Their blades contain 11 to 20 TPI and cut similar to crosscut saws.
Keyhole saws are used to make small holes in softer woods or drywall. Most have a single, pistol grip handle to which various blades can be fitted. Blades vary from 5 to 15 inches in length and contain 5 to 20 TPI, with 8 to 10 TPI being most common.
Coping saws are used to make curved cuts on thinner materials. They use a very thin metal blade with a U-shaped frame and wood or plastic handle to make turning cuts on wood, plastic, or metal depending on the selected blade. Blades usually have 12 to 15 TPI, but coarser and finer blades are available for specialized applications.
Hacksaws are used primarily for cutting plastic and metal pipes and other small household materials. Hacksaws utilize the same U-shaped frame structure as coping saws, and some models include adjustable frames to accommodate blade sizes from 8 to 12 inches. They have 14, 18, 24, or 32 TPI depending on the application needs.
Flush-cutting saws are double edged tools designed for trimming the ends of dowels, tenons, and other protrusions flush with the surface. The blade bends to lay flat on the flush surface and its teeth are angled upwards to prevent surface marring. The blade is about 6 inches long and usually has 11 TPI on one side and 20 TPI on the other for versatility.
Many other types of saws are available for a range of specialized cutting applications. Most saws are designed to cut on the push stroke. However some saws, such as Japanese saws, are made to cut only on the pull stroke.
A number of design parameters also must be considered once the type of hand saw is chosen, including the number of teeth, the drive mechanism, and the saw length and shape.
Number of Saw Teeth
The cutting tooth density on a saw blade is designated in teeth per inch (TPI). A denser blade (higher TPI) consists of smaller teeth for finer cuts and cutting smaller objects.
While most handsaw cutting types have manually powered designs, some also can be power driven. Advantages of power handsaws include higher cutting speeds than those achievable manually and better precision where physical exertion may lead to inaccuracies from an unskilled operator. Manual power is many times quicker however and offers more versatility and cutting control.
Saw Length and Size
Within each cutting type a saw can also vary by blade length and overall size. As saw blade length increases, cutting capability with each stroke increases but stability and strength near the end of the blade decreases. Similarly, a larger sized saw can cut larger workpieces at the sacrifice of versatility.
Image Credit -- Bosch Power Tools Division