When using projection welding, the spot weld symbol must be used with the projection welding process reference in the tail of the welding symbol.
The spot weld symbol must be centered on the reference line.
Embossments on the arrow side member of a joint for projection welding shall be indicated by placing the weld symbol on the side of the reference line toward the reader (fig. 3-72).
Embossment on the other side member of a joint for projection welding shall be indicated by placing the weld symbol on the -side of the reference line away from the reader (fig. 3-73).
Proportions of projections must be shown by a detail or other suitable means.
Dimensions of projection welds must be shown on the same side of the reference line as the weld symbol.
Size of Projection Welds
Projection welds must be dimensioned by strength. Circular projection welds may be dimensioned by size.
The size of circular projection welds shall be designated as the diameter of the weld expressed in fractions or in decimals in hundredths of an inch and shall be shown, with or without inch marks, to the left of the weld symbol (fig. 3-74).
The strength of projection welds shall be designated as the minimum acceptable shear strength in pounds per weld and shall be shown to the left of the weld symbol (fig. 3-75).
Spacing of Projection Welds
The pitch of projection welds shall be shown to the right of the weld symbol (fig. 3-76).
Number of Projection Welds
When a definite number of projection welds is desired in a certain joint, the number shall be shown in parentheses (F, fig. 3-77).
Extent of Projection Welding
When the projection welding extends less than the distance between abrupt changes in the direction of the welding or less than the full length of the joint, the extent shall be dimensioned (fig. 3-78).
Flush Resistance Seam Welded Joints. When the exposed surface of one member of a resistance seam welded joint is to be flush, that surface shall be indicated by adding the flush contour symbol to the weld symbol, observing the usual location significance (fig. 3-71).