The G.A.L. Gage Co. Cat # 8 Fillet Weld Gauge 7-Piece Sets GAL-8 is one of the quickest and easiest ways to check fillet weld leg length and fillet weld throat dimension against weld specifications is with a Fillet Weld Gauge. These gauges come in a variety of sets with sizes ranging from 1/8 of an inch to 3 inch in both inch or metric sizes.