The trainer

Gauge trainer

Knowing how a fillet leg is measured takes ten seconds to learn. Looking at a weld and saying what it is takes repetitions. This is the repetitions.

Fillet leg size

8 welds, one measurement each

Every cross-section is drawn to scale from generated geometry, so what you measure on screen is what the weld actually is. Being one graduation out scores half — that is the difference between a reading error and a guess.

The modes

Fillet leg size
Read the leg of a fillet weld off the cross-section, in sixteenths.
Convexity and concavity
Call the face contour and read how far it bulges or dishes.
Groove reinforcement
Read the height of the crown on a groove weld face.
Undercut depth
Read the depth of undercut at the weld toe on a scale overlay.
Discontinuity ID
Name the discontinuity from the weld surface or section.

Questions about the trainer

How are the welds generated?

Each cross-section is built from a seeded pseudo-random generator, then drawn to scale from that geometry. Nothing is a stock picture — the leg you measure on screen is exactly as long as the model says it is, which is what makes the grading meaningful.

Why does being one graduation out score differently?

Because reading a gauge is an analogue skill. Calling a 5/16 in. fillet 1/4 in. is a reading error worth correcting; calling it 1/2 in. means you were not measuring at all. A trainer that scores both as simply wrong teaches you nothing about which one you did.

Does this replace practising with a real gauge?

No. Nothing replaces putting a fillet gauge against real steel. What this does is give you the repetitions — hundreds of welds in an evening, each one graded — that a training coupon in a workshop cannot.

Is the trainer free?

Yes — every mode, unlimited rounds, no account and no payment. Rounds are 8 welds each and you can play as many as you like.

Read the theory alongside it

The trainer tells you what a weld measures. The discontinuity reference tells you why it got that way, and leg and throat geometry explains why a concave face has less strength than its leg size suggests.