Grrrr it's neither BSPP or NPT! It's just a tad smaller than BSPP so the BSPP to NPT adapter I bought won't even fit in the hole!

Just so were on the same page, this compressor is the bigger brother of the popular MV50 compressor.

Any ideas on what size threads this fitting actually has?

I was thinking as a last resource I will keep the fitting on the compressor and instead cut the end of the rubber hose attached to it and put standard fittings air into the end.

TIA!