Chapter 3 Welding Joints, Positions, and Symbols 61 welds, and plug and slot welds. This information also appears in the “S” position. The size of a spot weld is the diameter of the weld at the point where the two pieces of base metal contact each other. Groove weld size is given in parentheses in the “E” position on the welding symbol. Groove weld size is the depth to which the weld penetrates into the base metal. See Figure 3-30 for examples of depth of bevel and groove weld size. In Figure 3-30A, the depth of bevel is 1/4″ and the groove weld size is 3/8″. In Figure 3-30B, the “S” dimension states that the metal is cut to a depth of 3/8″ on both sides. The “E” dimension shows that the depth of the weld is 5/8″ on both sides. The required groove weld size (depth of weld) and depth of bevel (depth of preparation) are generally determined by welding codes or specifi cations, or by a welding engineer. When no groove weld size is shown for a single-groove or double-groove weld, complete Figure 3-28. Comparing the weld size and strength of a concave and a convex fi llet weld. The fi llet welds at A and B appear to be the same size (dimension “a”). The leg size (L1 and L2) appears the same in both welds. However, the actual weld size in A (S 1 ) is smaller than the actual weld size (S2) in B. Also, effective throat E1 is smaller than effective throat E 2 . E 1 S 1 E 2 S 2 a 1 a 2 L 1 A L 2 B Figure 3-29. Fillet weld size and shape. A—The single dimension indicates both legs are equal and 1/4″ in size. The depth of the weld is 3/16″. B—The fi nished weld. C—Two dimensions in parentheses indicate unequal legs. Relative size of the legs is shown on the working drawing. D—The fi nished weld. 1/4″ 1 4 × 1 2 Indicates on which part the long leg is made Long leg horizontal A B C D 1/4″ 1/4″ 1/4″ 1/2″ 1 4 Figure 3-30. The depth of the edge shape and groove weld size. A—The edge shape is cut 1/4″ deep. The weld size or depth of penetration is 3/8″. B—The edge shape is a double-V-groove. The edge shape is cut 3/8″ deep and the depth of penetration is 5/8″ on both sides of the joint. 1/4 (3/8) 3/8″ 1/4″ 5/8″ 1″ 3/8″ 5/8″ 3/8″ 5/8″ 3/8 (5/8) A B 3/8 (5/8)