What is the maximum thread depth achievable when cutting threads on a pipe?

The maximum thread depth achievable when cutting threads on a pipe can be understood through the standard practices in pipe threading techniques. When using a die to cut threads, it's common to allow for sufficient engagement of the threads, which typically leads to a recommendation to have at least two complete threads visible beyond the die itself once the threading process is complete. This ensures that the threads have adequate strength for mechanical applications, allowing proper connection with other threaded components.

This practice is essential because sufficient thread engagement is key to maintaining structural integrity, sealing capabilities, and overall performance of the pipe system. Having just one thread visible may not provide enough grip, while more than two threads can sometimes result in waste of material or unnecessary length beyond functional requirements.

In contrast, the other choices—such as equal to the diameter of the pipe, always twelve rotations, or depending on the tool used—do not accurately reflect the standard threading practices. The actual achievable maximum thread depth is not fixed to the diameter of the pipe in a direct manner, nor is it universally twelve rotations, as these factors vary based on application specifics. The depth does depend on the tool and material but primarily relates to the industry standard of ensuring two threads for a reliable fitting.