Pressure switch thread size question

[dobbslc]

I need some help with my compressor. The pressure switch seems to be knackered as it constantly leaks air while its running through the unloader valve.
Looks like its had a whack during the house move
I know the 3 outlets are 1/4" BSP (measured at 1/2" then take away 1/4")
But what size is the main inlet thread from the tank? It doesn't seem to resemble any normal size, are the eBay switches all basically the same?
I don't want to order the wrong pressure switch!

 

[gordon stephenson]

Looks like it could be 3/8" bsp,

 

[frank horton]

they are always BSP unless stated otherwise.....never known anything but BSP and that's wherever u are in the world........

 

[dobbslc]

The stubb from the tank measures 0.640 ish of an inch so not sure what that is in BSP sizing
Are they all the same on normal compressors?

 

[rtbcomp]

Look in the links section, there's a link to thread size tables.

BSP sizes refer to the pipe and not the thread diameters.

 

[brightspark]

here https://www.castrads.com/frequently...-iron-radiator-renovation/what-are-bsp-sizes/ just measured a half inch nipple it comes out a .820 imperial outer thread

 

[Jetex]

0.656 major diameter is 3/8 BSP

 

[thinfourth]

BSP or BSPT or NPT

Lights blue touch paper


RUNsss

 

[waldershelf]

BSP or BSPT or NPT

Lights blue touch paper


RUNsss

BSP is a parallel thread, BSPT is a taper thread, NPT is a different system although one or two sizes actually match the equivalent BSP Not really controversial at all.