I am familiar with the metric system but am trying to learn about IMP, BSP, UTS, BSW and others but it`s a bit confusing at times.
I just bought an airbrush kit, to be able to attach this to my air compressor I need an adapter of some kind. I measured the threads on the airbrush gun and found it to be 9.5mm, as I know these things are measured in inches I found that this is around 3/8 of an inch (25.4mm/8x3) but not in this case...!
I went on ebay and bought a 3/8 BSP female adapter, when this arrived it was actually 15-16mm internal thread diameter, not 9.5mm as I expected.
I then