This time you do the same as you would when checking for permissible convexity. Permissible tolerance of concavity and underfill The gauge will indicate if there is too much reinforcement. Slide the pointer down, this time until it touches the face of the weld. Using the end of the gage that has the 45-degree angle sides, bring the gauge until it touches both pieces being welded. The size of the fillet weld will be indicated by the gauge. Place the gauge against the toe of the weld and slide the pointer down towards the bottom piece of the structure being welded. There are several things it can measure: Size of a fillet weld If there is daylight between the face of the weld and this end of the gauge, the weld is concave and is no longer an acceptable 1/2″ fillet.Īn AWS Gauge, however, is more versatile than the Standard Fillet Gauge. The protrusion in the middle of the gauge should make contact with the weld, verifying that the weld is not concave. Generally, welds should never be concave.

Once you have determined that the weld is properly sized at 1/2″, then test for concavity or convexity. The vertical line will show where the bottom toe should be. This is particularly useful with big fillet welds where gravity tends to make the bottom leg larger.

The bottom edge of the fillet has more room, which allows for a larger leg size. If you have space between the gauge and the toe of the weld, then the weld is undersized. This end should be exactly at the top edge of the weld to be a 1/2″ fillet. Simply slide the gauge and have the top end rest against the vertical piece. This type of gauge will typically include 7 or more pieces.įor example, here are some instructions on how to use a 1/2″ fillet weld: The Fillet Weld Gauge will let you know if your weld is concave. We always want our welds to be from flat to slightly convex. The Fillet Weld Gauge is one of the easiest gauges to use, and is helpful to check welds for fillet size and concavity. This article will show you how to use both gauges properly. The two most used kinds are the Standard Fillet Weld Gauge and AWS Gauge (Automatic Weld Size Gauge). There are several types of gauges used in measuring welds and welding defects including but not limited to porosity, undercut, underfill and concavity.

Fillet weld tolerance