How many turns should a properly threaded pipe be able to screw into a fitting by hand?

A properly threaded pipe should be able to screw into a fitting by hand for a distance of approximately 3 to 3-1/4 turns. This range ensures that the threads on the pipe and fitting are compatible and that there is adequate engagement for a secure connection.

Having this amount of engagement is crucial for creating a leak-free joint. If the threads do not match up properly or do not engage adequately, it could lead to a compromised seal, resulting in leaks under pressure. The 3 to 3-1/4 turns represent a well-engineered design that balances ease of assembly and the necessity for a tight, reliable connection.