Carbon Steel: Recommended for general use by engineers, mechanics, electricians, plumbers and maintenance men. Tungsten Alloy Steel: Resist breakage, longer wearing and give satisfaction where fast, dependable results are essential. High Speed Steel: Heat resistant and suitable for cutting tough alloy steel. Choose the right blades for the right works. 14 Teeth Per 25.4 mm: For cutting soft solid steel, iron, rails, brass, bronze, copper and aluminium. 18 Teeth Per 25.4 mm: For cutting tool steels, iron pipes and light angle iron. 24 Teeth Per 25.4 mm: For cutting drill rods, medium sheet metal, tubing and solid brass. 32 Teeth Per 25.4 mm: For cutting thin sheet metal and thin wall tubing.