probaly just like the BSPP, like evrything else, and gave it ther owne standard name
But you can try here http://www.gewinde-normen.de/en/whitworth-pipe-thr
BSPP/BSPF is equivalent to JIS PF
Did you gauge the threads prior to shipment to ensure they were machined properly?
Maybe one is using a tapered gauge?
Well, not me personally... not my place, really. But I'm sure they did. I'm thinking our customer doesn't have the thread (or gauge) they think they have... some kind of oddball JIS variant monster or something. I REALLY am hoping they aren't using a tapered gauge... funny as it might be.