Why will be the threads G 1/8 and 1/8 NPT offered for pressures only to a nominal pressure range of 400 bar? Where does this limit result from?
Basically, digital pressure gauge is simple: From the certain pressure limit, the thread flanks are no more ?strong? enough to resist the force of the applied pressure. If diaphragm seal is too high, there is a threat of shearing for the thread. By the way, the pressure limits come from DIN EN 837-1.
diaphragm seal : The maximum pressure around which a thread may be used depends not merely on the thread diameter, but additionally on the selected sealing type and the material of the counter-thread.