Comment by malfist
4 hours ago
The cap is rigid. Either the threads constrain movement or they don't. A section of threads that allow for movement would still find the overall system constrained by other threading.
4 hours ago
The cap is rigid. Either the threads constrain movement or they don't. A section of threads that allow for movement would still find the overall system constrained by other threading.
The pitch stays the same. The simplest way is tapered threading with a sufficiently deep groove to retain when only the first few threads are engaged. Less simple is a custom male profile that transitions into a squared ACME like profile to let gas leak by.