Spot weld
A circle on the reference line: a spot weld, a resistance weld that joins sheets at a single point.
This explains what a symbol specifies on a drawing. It isn't welding instruction, and a drawing's own notes and the governing code take precedence.
How to read it
Spot welding is a resistance welding process: the parts are held together under pressure between electrodes, and an electric current through them produces the heat that fuses them. The Navy's Steelworker course calls it probably the most commonly used type of resistance welding, and especially useful for sheet metal parts.
Resistance spot weld symbols have no arrow side or other side significance in themselves, which is why the symbol is centered on the reference line.
More welding symbols
Sources
- Steelworker, Volume 1, NAVEDTRA 14250, 1996, Naval Education and Training Professional Development and Technology Center, U.S. Navy (Internet Archive), Chapter 3, Drawings and specifications
- Welding Theory and Application, TM 9-237, 1967, Department of the Army (Internet Archive), Glossary; chapter 11, section II
- Scheme of symbols for welding, IS 813:1986, Bureau of Indian Standards (Internet Archive, Public.Resource.Org), Table 1
Last reviewed September 25, 2026 by Rory Hansen. How we research