Fillet weld
A right triangle on the reference line: a fillet weld, the triangular weld that joins two surfaces meeting at about a right angle.
How to read it
A fillet weld has a roughly triangular cross section. It joins two surfaces at approximately right angles to each other, as in a lap, tee or corner joint.
The symbol is drawn with its vertical leg to the left of its slanted leg, whichever way the joint faces. The same rule holds for the bevel, J-groove and flare-bevel symbols. Below the reference line, the symbol calls for a fillet weld on the arrow side of the joint; above it, on the other side; on both sides of the line, fillet welds on both sides of the joint.
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.
Contours
A contour symbol beside the fillet symbol says how the weld's face is to be formed: flush, convex or concave.
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Read next
- Next in Welding symbolsSquare groove weldTwo short parallel lines on the reference line: a square groove weld, one of the groove welds that join two members edge to edge.
- The same shape in Multimeter symbolsDiode test symbolThe diode test setting. The symbol is the circuit symbol for a diode, a triangle pointing at a bar; on this setting the meter shows the voltage drop across a diode, or OL.
More welding symbols
The same shape elsewhere
Browse symbols drawn with arrows, lines or triangles.
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
- Scheme of symbols for welding, IS 813:1986, Bureau of Indian Standards (Internet Archive, Public.Resource.Org), Tables 1 and 2
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 25, 2026. How we research
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