Projection Weld Symbol
A projection weld is a resistance weld localized by a prepared projection or embossment on one of the members.
- Identify the formed projection that localizes a resistance weld
- Separate weld size, count, pitch, and strength information
- Verify projection geometry and electrode access before production
A correct icon is not yet a correct decision.
Projection welds can resemble spot or plug instructions on a simplified print, but the part must contain a formed feature that localizes current and force. Missing that physical evidence changes tooling, process setup, and joint preparation.
What each mark tells you—and what it does not.
Use the third column as a stop-check. It prevents a familiar mark from turning into an unsupported assumption.
| Visual cue | What it tells you | What you must still verify |
|---|---|---|
| Formed projection in the detail | Physical feature used to localize resistance-welding current and force | Confirm shape, height, member stack-up, and which member carries it. |
| Value to the left | Projection-weld size under the current AWS convention | Do not substitute strength; put a required strength in a note or tail. |
| Parenthesized count and pitch | Number of welds and their center-to-center spacing | Locate the first/last weld and confirm the detail pattern. |
| Tail, note, and process detail | Carries strength or process information not encoded by the elementary symbol | Check electrode access, procedure qualification, and acceptance criteria. |
Six embossed projections attach a bracket to sheet
The callout shows 1/4 to the left, (6), and 2-unit pitch, while the bracket detail shows six formed dimples.
Confirm the formed projections first, then read 1/4 as size, (6) as quantity, and 2 as center-to-center pitch. Use a note or tail for any required strength and process information.
The layout is released as six sized projection welds at the stated pitch, with tooling, access, and acceptance verified instead of being converted into a six-hole plug-weld pattern.
How to read it without guessing
Inspect the joint detail to locate the projection and the members it brings into contact. Read weld size, number, and pitch in their applicable positions; use the tail or notes for process and strength information when required.
- Inspect the joint detail to locate the projection and the members it brings into contact.
- Read weld size, number, and pitch in their applicable positions; use the tail or notes for process and strength information when required.
- Projection welding uses a formed projection to localize current and force; a plug weld fills a prepared opening with weld metal.
- Verify projection geometry, member arrangement, process note, number, pitch, electrode access, and acceptance requirements.
Six embossed projections attach a bracket to sheet
The callout shows 1/4 to the left, (6), and 2-unit pitch, while the bracket detail shows six formed dimples.
Rotated view: locate the joint from “Formed projection in the detail,” not page direction.
Crowded callout: keep “Value to the left” separate from “Parenthesized count and pitch”.
Off-view requirement: stop if “Verify tooling, electrode access, qualification, and acceptance” is not available.
Write one defensible instruction for the Projection Weld. Name the physical joint or surface, state what the visible cue controls, and identify the final item that must be verified before release.
Reveal the expert read +
Confirm the formed projections first, then read 1/4 as size, (6) as quantity, and 2 as center-to-center pitch. Use a note or tail for any required strength and process information. The layout is released as six sized projection welds at the stated pitch, with tooling, access, and acceptance verified instead of being converted into a six-hole plug-weld pattern.
Similar-looking instructions, different fabrication decisions
Projection weld
Uses a formed projection or embossment
DECIDING CHECKCan you point to the projection in the part detail?Spot weld
Joins members at a localized point without a prepared projection requirement
DECIDING CHECKDoes the process rely on the member stack rather than an embossment?Plug weld
Deposits weld metal through a prepared opening
DECIDING CHECKIs there an actual hole or slot to fill?Three mistakes that change the instruction
Treating it like a plug weld
A projection weld localizes resistance-welding current at a formed projection; a plug weld deposits metal into a prepared opening.
Swapping count and pitch
A parenthesized quantity and a spacing value do different jobs. Read each by its position before laying out the pattern.
Ignoring the formed feature
The symbol does not define projection height, shape, member thickness, electrode access, or process setup. Those requirements need the detail and procedure.
Projection Weld practice
Recognition → evidence → field release
Skill: joint evidence
Which physical feature distinguishes a projection weld from a plug weld?
Five checks for this symbol
This is a drawing-reading checklist, not an acceptance standard. Use it before fabrication, fit-up, inspection, or answering a test question.
- 01Locate every formed projection
- 02Read weld size separately from count
- 03Read pitch and anchor the pattern
- 04Find strength/process information in notes or tail
- 05Verify tooling, electrode access, qualification, and acceptance
Standards and editorial basis
This guide teaches common AWS-style drawing interpretation. It is educational material, not a substitute for the purchased standard, project specification, code, WPS, or qualified engineering direction.
Editorial method. Original training diagrams, worked decisions, misconception checks, and questions are written for learning—not copied from a standards table. Production interpretation must still follow the governing documents.
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Related symbol guides
Spot & Seam Welds
Plug & Slot Welds
Size, Length & PitchEducational practice only. Verify production work against the governing drawing, applicable standard, WPS, and qualified instruction.