INFORMATION: The parts of an automobile must be securely fastened together. When it is necess
to remove parts for replacement or repair they should be removable with a minimum
effort and time. There are two types of threads commonly used, they are N. C. nat
coarse and N. F. national fine. The characteristics of a fine thread are, there a
more threads per Inch and shallower threads and the course thread has less thread
Inch and deeper threads. The advantages of fine threads are they are stronger, d
work loose with vibration and can be used for adjustment. The advantages of coar
threads are they are not easily cross threaded and because of the depth of the the
they hold better in soft metals such as cast iron and aluminum,
PROCEDURE
1. Obtain six assorted bolts.
2. Using a ruler and a torque table chart: gather the information needed to fill
the blanks in the chart below.
3. Show Instructor when blanks are filled, be prepared to answer questions.
BOLT BOLT
BOLT THREAD WRENCH TORQUE
NUMBER DIAMETER LENGTH TYPE SIZE LIMITS
3
2
3
5
6
QUESTIONS:
1. State all the infomation needed to order a cap scret
2. List the advantages of a fine and course thread.
3. Describe how a lockwasher prevents a cap screw er z mut fron loosening.
4. State the characteristics of a fire and course threx.