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Engineering
Grade 9-12
Welding Symbols & Joint Types Reference Cheat Sheet
A printable reference covering AWS welding symbol anatomy, common weld symbols, joint types, and arrow side placement for grades 9-12.
Related Worksheets
This cheat sheet covers the basic welding symbols and joint types used on engineering and fabrication drawings. Students need it because welding instructions are often shown with compact symbols instead of long written notes. Reading these symbols correctly helps a builder know what type of weld to make, where to place it, and how large it should be. It is especially useful for design, manufacturing, robotics, and shop projects.
Key Facts
- The reference line is the main horizontal line of a welding symbol, and weld information is placed above or below it.
- A weld symbol below the reference line means the weld is made on the arrow side of the joint.
- A weld symbol above the reference line means the weld is made on the other side of the joint.
- A fillet weld symbol is a right triangle, and its size is usually written to the left of the symbol, such as 1/4 fillet weld.
- A groove weld symbol shows the prepared edge shape, such as square, V, bevel, U, or J groove.
- The length of a weld is written to the right of the weld symbol, such as 3 meaning a 3 inch weld.
- Intermittent welds use length and pitch notation, such as 2-6 meaning 2 inch weld segments spaced 6 inches center to center.
- A circle at the junction of the arrow and reference line means weld all around the joint.
Vocabulary
- Welding symbol
- A complete drawing notation that shows the weld type, location, size, length, and other instructions.
- Weld symbol
- The small shape inside a welding symbol that identifies the type of weld, such as fillet, groove, plug, or spot.
- Reference line
- The horizontal line that carries weld symbols and separates arrow-side information from other-side information.
- Arrow side
- The side of the joint that the arrow points to on the drawing.
- Fillet weld
- A triangular weld used to join two surfaces that meet at about a right angle, such as a T joint or lap joint.
- Groove weld
- A weld made in a prepared opening or groove between two parts to join them along an edge.
Common Mistakes to Avoid
- Confusing weld symbol with welding symbol is wrong because the weld symbol is only the small shape, while the welding symbol includes the reference line, arrow, tail, and dimensions.
- Putting an arrow-side weld above the reference line is wrong because AWS notation places arrow-side weld information below the reference line.
- Reading pitch as weld length is wrong because in notation like 2-6, the first number is segment length and the second number is spacing center to center.
- Ignoring the tail is wrong because the tail may include important process or specification notes such as SMAW, GMAW, or a welding procedure reference.
- Assuming every joint uses the same weld type is wrong because butt, lap, T, corner, and edge joints can require different weld symbols and preparation.
Practice Questions
- 1 A fillet weld symbol is below the reference line with 1/4 written to the left and 3 written to the right. What size and length of weld is required, and on which side is it placed?
- 2 An intermittent fillet weld is labeled 2-6 to the right of the weld symbol. What is the weld segment length and what is the pitch?
- 3 A weld symbol appears above the reference line, and a circle appears where the arrow meets the reference line. What do these two symbol features mean?
- 4 A designer chooses a lap joint for two overlapping plates instead of a butt joint. Explain why the weld symbol and side placement must still be read carefully before fabrication.