And what size in MM is 5/8, 3/4 and 1/2 ?

 

British Standard Pipe is measured in the bore of the pipe i think. 3/4 is near as damn it spot on 19mm, 1/2" is bout 12mm, and 5/8 isn't anyhing. The equasion is imperial - mm is x 25.4, and divide it for mm to imp. Hope that helps.

 

So i measure it this way......


OR this way......

 

If you have a Zeus book, you can measure it anyway you want, cause it has all the dim's in. Although that looks like it could be 5/8 Bsp. do you have the bit it screws into?

 

5/8 is approx 15-16 mm...

 

You've been reading the vernier, you cheat

 

To be assured of any fitting you need three components....internal bore, extrernal size, thread pitch those should enable you with a zeus table to be assured you have the correct size and type BSP, NPT, Metric etc...

HTH

Ian