Question

1. which of the following thread designs typically has tapered threads to provide for sealing at a joint? a. unc b. npt c. unf d. unef

Explanation:

• UNC (Unified National Coarse): It is a type of thread with a coarse pitch. It is mainly used for general - purpose fastening and does not have tapered threads for sealing.
• NPT (National Pipe Thread): NPT threads are tapered. The taper of the threads helps in creating a seal at the joint. As the male and female NPT threads are tightened, the interference due to the taper creates a seal.
• UNF (Unified National Fine): It has a fine pitch and is used for applications where a higher tensile strength is required for a given diameter. It is not designed for sealing at joints through tapered threads.
• UNEF (Unified National Extra - Fine): It has an extra - fine pitch. It is used in applications where a very fine adjustment or a high - strength connection with a small diameter is needed. It is not for sealing at joints via tapered threads.

Answer:

B. NPT