M20 to be specific,
Hopefully help is appreciated somewhere......
Regards
Although
@Lons beat me to it, I can't let that go!!!
'Help' is greatly appreciated
when the information is accurate. I've only noticed two posts from
@Seascaper and both have offered inaccurate information! As has already been said, 3/4" is 19.05mm not 20 and an M20 thread is 2.5mm pitch not 2. For the benefit of
@Seascaper, the use of the prefix 'M' for metric threads - without further reference to the pitch - means that it belongs to the Course Series. If the pitch is anything other than the Course Standard then the pitch has to be specified as well. Even a Fine Series M20 has to be specified as M20-1.5.
20mm x 2mm is a non-standard so should always be referenced thus.
Personally, I don't actually like the designations shown in Lons' attachment since it promotes the use of non-standard OD/Pitch combinations as though they were 'Standard'.