When an object consists of a number of separate assembled units that comprise the complete assembly, the individual units are often drawn as subassemblies. The main or top assembly is first prepared and the subas­semblies are identified on the print by a letter or a number and a name for referencing purposes. A drawing for each subassembly is then prepared, and each is identified by the letter or number and name found on the main assembly. Note that in many cases, subassembly drawings may consist of several views and may be shown in an enlarged detail. These drawings are helpful in the interpretation of prints and the assembly of parts; also, they facilitate the preparation of bills of materials. As a rule, a bill of materials is prepared for each subassembly and shown in a ruled space on the drawing.

FIGURE 9.2 ■ Assembly print.


Refer to the drawing, Adjustable Bumper Hitch Details, page 116

1. What are the dimensions for distances ©

(@, W, (X, © , and?

15. Make a complete list of materials that will be required to complete the order. Include overall dimensions.







2. Why is it unnecessary to show the details for parts ©, ©, and © ?

Bill of Materials




16. From what material are all parts of the assembly to be made?

3. What are the maximum lengths of the following dimensions: 5/8", 87/8", and 6%"?

17. What does a subassembly print represent?




18. Give three reasons for preparing a subassembly drawing.

4. Explain the significance of the dimension 1/2"—13 UNC.

5. Give a reason for showing only one assembly view

19. List two terms used to identify a complete assembly drawing.

6. What is the maximum diameter for the bumper clamp thread specification?

20. Give two reasons for preparing an assembly drawing.

7. Which line in the assembly print represents surface?

21. a. After reviewing foldout drawing 9 “Mandrel Puller Ass’y.”, list the instructions for its assembly.

8. Which point in the detail represents point?

9. Which corner in the detail represents corner

b. Interpret the following items found in the assembly instructions:

1. DR. 7/16 (0.4370) THRU (4X)______________

2. HEX. HD. MACH. SCR. 3/8—16 X 1/2 LG.

10. Which point in the assembly represents corner?

11. What is the largest overall length to which the hitch may be adjusted?

3. 3/8—16 NUT (4X)_______________________

c. Explain the purpose of the reference dimen - sion(s). (((((((((((((((((((((((((((((((

12. How many slots will there be in the completed bumper hitch?

13. How many drilled holes will there be in the completed bumper hitch?

22. What is the total number of pieces required to make the Mandrel Pulley?

14. How many inches of thread must be cut to complete the order? Disregard stock items.

23. What is the total weight of the Mandrel Pulley?

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