A piercing saw is a type of saw commonly used in jewelry making on sheet metal. It is usually used on softer metals as the saw is delicate.[1][2]
A piercing saw is shaped like a smaller coping saw. The blade is held in tension in a metal frame. The frame throat size can range from 50 to 200 mm (2.0 to 7.9 in).[1][3]
Saw blades come in many different thicknesses and your blade selection will depend on the material being sawn and nature of the work being done. For very fine delicate work, and for cutting very thin material use a finer blade, and for general purpose cutting a heavier blade. Saw blades have a range of sizes, from finest to coarsest: 8/0, 7/0, 6/0, 5/0, 4/0, 3/0, 2/0, 1/0, 00, 0, 1, 2, 3, 4, 5, 6.[3]