The flat or flush-contour symbol and method of finish may be added to the spot-weld symbol when the exposed surface of either member of the spot-welded joint is to be made flush or flat, Figure 18.12 and Figure 18.13. Note that a machine finish may be specified as flat without a need for it to be flush by adding a note in the tail “machine flat,” Figure 18.12.

FIGURE 18.13 ■ Application of flush - or flat-contour symbol.

Multiple-Member Spot Welds

Multiple-joint spot welds include one or more pieces inserted between the two outer members. The same spot - weld symbol and the same elements are applied in this case as for a two-member joint, Figure 18.14.

UNIT 18: REVIEW

Graph paper is provided at the end of this review for your use.

1. Using sketches, show how the spot-weld symbol differs from the weld-all-around symbol.

2. On what side of the reference line are dimensions applied to the spot-weld symbol?

7. Give the significance of each dimension shown in the following symbols.

3. Is it necessary to use a tail with the spot-weld symbol?

Explain.

4. What does the term pitch refer to when applied to the spot-weld symbol?

Apply a welding symbol to the following sketch to indicate seven spot welds on the horizontal centerline between the 15" dimension, spaced 21/2" apart, size of spot weld to be %", and the process to be resistance spot welding.

5. List five dimensions or other information that may be applied to the spot-weld symbol.

6. Identify the dimension shown with each of the following spot-weld symbols:

(3)

rs«>——у <G1

9. Show where the spot-weld symbol should be located on the reference line for the weld shown in the following sketch. Include an RSW process reference.

10. Sketch the weld called for by the following symbol.

11. a. Sketch the desired weld as indicated by the following welding symbol. Apply it to the sketch shown on the right.

13. Apply the data for spot welds shown in Sketch “A” to Sketch “B” by means of a welding symbol.

b. On the sketch, show the significance of the

0. 25 figure.

c. Identify the type of joint that is shown in the sketch.

d. If a figure of 200 lbs were shown in place of the 0.25, what would it signify?

e. If a figure of 200N is shown, what does it signify?

f. If a figure of 30 mm is shown, what does it signify?

14. Sketch an enlarged detail of the portion of the fan rotor that is circled by a broken line. Apply a spot-weld symbol to this detail that signifies four spots 0.25" diameter and spaced 1" apart. The spot welds are to be made on the outside surface of the ring beginning 1/2" from the outer circumference. Include an appropriate welding process reference on the welding symbol. Also indicate the spot welds that are to be finished flush by grinding.

12. a. Describe the locations of the required welds as they would appear in the sketch below.

b. Indicate on the sketch below the location of the weld specified by the weld symbol given.

c. Indicate on the sketches below how the welds will appear.