Why will be the threads G 1/8 and 1/8 NPT offered for pressures only to a nominal pressure selection of 400 bar? Where does this limit result from?
Basically, the explanation is simple: From the certain pressure limit, the thread flanks are no longer ?strong? enough to resist pressure gauge 10 bar of the applied pressure. If the pressure is too much, there is a risk of shearing for the thread. By pressure gauge 10 bar , the pressure limits come from DIN EN 837-1.
Attention: The utmost 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.