If a bath tap had an inlet of 15mm

stevie1, Mar 8, 8:21am
is this how far it winds onto the pipe!

russ18, Mar 8, 8:24am
No that's the thread size - 15mm or 20mm.

stevie1, Mar 8, 8:31am
Buggar, found some taps on here too small. I'm putting back a bath which I took out 20 years ago and can't quite get into the space at the moment but the pipes seem to be bigger than a 20mm thread even could even be 25 mm

emz24, Mar 8, 8:47am
Doubt it will be 25mm. Have never seen any 25mm taps.
Most bath taps are usually 20mm BSP threads.

atlantis3, Mar 8, 8:50am
Bath taps are usually the larger ones 15mm refers to the inside diameter of the pipe a bit confusing because 15mm is equal to a 1/2 inch pipe and 20mm is equal to a 3/4 pipe. Im guessing that the 25mm (outside diameter) you are measuring is actually on20mm pipe ( inside nominal bore size) (or 3/4 inch british standardpipe tapered-BSPT)

stevie1, Apr 8, 9:14am
yeah what made me wonder is the hexagon cap thats on there is 30mm wide and I wouldn't have thought that there would be a 5mm thickness either side, but as you say its the inner thread measurement