§6.1 & §6.2 Side SignificanceArrow Side vs Other Side on a Weld Symbol
The rule is fixed: below the reference line = arrow side. Above = other side. Not all weld types have side significance — stud and surfacing welds are arrow-side only.
§6.2.1). Weld symbols placed above the reference line apply to the other side (§6.2.2). A symbol on both sides of the reference line means weld both sides (§6.2.3). The terms "arrow side" and "other side" are the official AWS A2.4 terminology.
§6.2.1–§6.2.3The Rule — Below and Above the Reference Line
The reference line is the horizontal line that is the backbone of every welding symbol. Where the weld symbol sits relative to that line determines which side of the joint gets welded.
| Position | Side | A2.4 Citation |
|---|---|---|
| Below the reference line | Arrow Side | §6.2.1 |
| Above the reference line | Other Side | §6.2.2 |
| Both sides of the reference line | Arrow + Other | §6.2.3 |
"Arrow side" does not mean the left side, right side, top, or bottom of a drawing. It means the physical side of the joint where the arrow makes contact. The same symbol can apply to the top, bottom, or either face of a joint depending on how the arrow is drawn.
§6.1.1–§6.1.4Side Significance by Weld Type
Not all weld types use arrow side and other side the same way. A2.4 §6.1 divides weld symbols into four categories.
| Weld Types | Side Rule | Citation |
|---|---|---|
| Fillet, groove, edge welds | Arrow contacts the outer surface of one joint member. That member's side = arrow side. | §6.1.1 |
| Plug, slot, spot, projection, seam welds | Arrow contacts the outer surface of one member at the centerline of the desired weld. The member the arrow points toward = arrow-side member. | §6.1.2 |
| Resistance spot (RSW), resistance seam (RSEW) | No Side Significance | §6.1.3 + §11.1.1.3, §12.1.1.3 |
| Stud welds, surfacing welds | Arrow Side Only — applied on a surface, not at a joint | §6.1.4 |
For RSW and RSEW: §6.1.3 states that some weld symbols have no arrow-side or other-side significance. The process-specific confirmation for resistance spot welds appears in §11.1.1.3, and for resistance seam welds in §12.1.1.3. Supplementary symbols used alongside these may still have side significance.
Arrow Side and Other Side FAQ
§6.2.1, weld symbols placed below the reference line apply to the arrow side of the joint. The arrow contacts the outer surface of one joint member — that member's side is the arrow side. The term does not refer to absolute position on the drawing; it refers to the physical side of the joint at the arrow location.§6.2.2, weld symbols placed above the reference line apply to the other side. A weld symbol on both sides of the reference line means weld both sides of the joint, per §6.2.3.§6.1.3, some weld symbols have no arrow-side or other-side significance. For resistance spot welds (RSW) and resistance seam welds (RSEW), this is confirmed in §11.1.1.3 and §12.1.1.3 respectively. Per §6.1.4, stud welds and surfacing welds are arrow-side only — they are applied on a surface rather than at a joint and are never shown as other-side welds.§6.2.1 and §6.2.2. A second common mistake is welding only the arrow side when a symbol appears on both sides of the reference line, which means both sides must be welded per §6.2.3.