The cutting capacity of a sprue cutter is the maximum thickness of wire that it can safely cut without damaging the cutting edges or bending the jaws.
The cutting capacity is based on the recommended cutting area of the jaws, which is from the centre of the cutting edge to the base of the jaws. The cutting capacity of the jaws is greatly reduced outside this area.
Sprue cutters will often have two cutting capacities listed: one for soft materials such as plastic, aluminium, gold and copper; and another for hard materials such as steel, platinum and nickel.
The cutting capacity can be listed either as a metric measurement of wire thickness, or using the American wire gauge (AWG) system.
What is AWG?
AWG is a standardised system of measuring wire thickness. It was first used in 1857 and became the favoured system for measuring wire thickness in North America, where it is still often used today. Unlike the metric measurement of wire thickness, an increase in the AWG number denotes a decrease in the thickness of the wire, so 20AWG is thinner than 5AWG.
What cutting capacity is required?
Manufacturers will usually state what type of use a sprue cutter is suitable for along with its cutting capacity.
Generally speaking a sprue cutter with a cutting capacity of up to 1mm (18AWG) will be suitable for model making with soft non-ferrous metals and plastic, one with a capacity of up to 2mm (12AWG) will be suitable for small electronic work and one with a capacity of up to 3.25mm (8AWG) will be designed for use in jewellery work, or with harder metals.