[kaminc]

Hello All,

I could use some advice on metric threads for a project. I need to develop threads for a high stress application (firearm barrel/breech). I have selected 30 MM for the size but I am not sure what pitch, standard or class to use. Material is 4130 chrome moly steel. I will be making both parts, (internal/external threads). I would imagine a thread with tighter tolerances than fastener specs. Also if anyone could supply torque specs for this thread/material combination.

Thanks,
Denis

[x3UK]

Hello All,

I could use some advice on metric threads for a project. I need to develop threads for a high stress application (firearm barrel/breech). I have selected 30 MM for the size but I am not sure what pitch, standard or class to use. Material is 4130 chrome moly steel. I will be making both parts, (internal/external threads). I would imagine a thread with tighter tolerances than fastener specs. Also if anyone could supply torque specs for this thread/material combination.

Thanks,
Denis

I would suggest that you start the design process the right way. Work out the loads and then select the correct thread, in size, depth of engagement, number of engaged threads and material properties etc, to suit, not choose a thread and try and manipulate it. I would not want to be near any impulsive loaded pressure vessel where the design had not been properly calculated and then hydraulically proof tested.

[yancho]

If a motor rotor must be of a trapezoidal or square thread. If it's about tenacity select a finer pitch (1.5 or 2 mm.). When selecting a normal nut, it has a width of 0.7 of the diameter of the thread, where high-pressure path 1 diameter. On this site there are all necessary standards for threads: Paralleles Whitworth Rohrgewinde DIN ISO 228 (DIN 259). Yancho