Sam Buscemi

John: You were right to quote the European member as saying the threads where of the Whitworth configuration but 1/16 x 30 is incorrect. The size is 3/16" x 32 Threads per inch. That would be simplified as 3/16 x 32 tpi. With 4.5MM x .8 pitch being another Whitworth configuration from my research a rare thread size used by different manufacturers, when I don't know or which one who may have used this rare size from time to time. So you know, the barrel threads are also of Whitworth confirgation which are 18MM x 1.27 pitch. On the grips screws you will find the 4.5MM to be sloppy in a 3/16" threaded hole and the 3/16" screws to bind in the 4.5MM threaded hole. Easiest thing to do is not force anything but run the right size tap through the frame and use matching die on the proper screw and you will have a perfect fit. I wouldn't recommend trying to rethread either to the other size because there is just not enought metal on the screw or frame to do such an operation. I hope this helps. P.S. Hugh Clark has a complete set of all of the above mentioned dies and taps and am sure can do any rethreading job you might need done.