Types of saws and milling cutters
A metal hacksaw consists of a frame, a handle, a blade and the tension screw with its wing nut. An adjustable frame takes blades of different lengths, so it is handy. A blade that is not tightened will bend and snap. Sawing means cutting a rolled metal blank into pieces. A milling cutter is a multi-edge cutting tool: each tooth acts as a cutter and removes a small chip, the teeth work in turn and cool in between. Types include cylindrical, disc, angular and end cutters. Cutters are used only on a machine, and that work is done by trained adults.
Naming parts: pupils write the names of parts marked 1–7 on a hacksaw picture (frame, handle, blade, pin, screw, wing nut). A real saw is examined only with the teacher; the blade teeth are sharp, so they are not touched.