In plain terms, leg is the spread of the weld metal along the legs of two base metals aligned perpendicular to each other. Leg length is a bit easier to understand, and does not require understanding lot of the math as is required for calculating throat thickness. Throat and leg length in a fillet weld Leg Length The throat thickness is reckoned by the extent of movement available to the protrusion available in the middle of the gauge. In order to calculate it, the device must be laid so that it meets the two parts of the weld that are perpendicular to one another, thus creating an isosceles triangle. The throat thickness is an important dimension of fillet welds. See the illustration in the figure below. Its dimension is calculated as 0.707 times the leg length of the fillet. The throat size or throat thickness is the shortest distance from the corner of the joint to the hypotenuse of the largest right angled triangle that can be inscribed in the fillet weld. These two are the most commonplace usages of the fillet gauge.
Before you learn how to use a fillet gauge measure for these measurements, it is important to know exactly the meaning of these two terms. Final Thoughts What Does a Fillet Gauge Measure?Īs I mentioned above, fillet gauge is used commonly for measuring throat thickness and leg length of a fillet weld.
