[RHD]

I have just checked. 30 tpi, but it measures 5/16". I have tried all combinations of new screws into old shafts etc and no matter what combination I have they all fit 100% as I suspected.
Another line of thought. Have you ever tried fitting a 30 repro dash lamp cap onto an original base. Just won't go by a minute amount. You would think, whoever made the repro caps would at lease get their measurements right. No way will I ever be buying any more repro caps, that's for sure.