Weld Joint Alignment Tool

A guide for welders, fitters, and inspectors on identifying and correcting common joint alignment issues before welding.

Select an Alignment Issue

Choose a common fit-up problem to learn how to identify and correct it.

Hi-Lo (High-Low Misalignment)

This occurs when the internal or external surfaces of two pipes or plates are not aligned flush with each other.

Correction Method:

Use a pipe clamp with alignment screws to adjust the pipes until the surfaces are flush. For plates, use wedges and tack welds to hold them in position.

Common Tools Used:

Hi-Lo Gauge, Straight Edge

Fit-Up: The Foundation of Quality Welding

A good weld starts long before the arc is struck. It starts with a good "fit-up"—the process of aligning and securing the parts to be welded. Poor alignment is a primary cause of weld defects. It can make it impossible to achieve proper root penetration, lead to inconsistent weld size, and create stress concentrations in the final joint. A skilled fitter spends the majority of their time ensuring the alignment is perfect before calling in the welder.