Being located outside the UK (or US), one problem we face in maintaining old steam locomotives is the mixture between different screw threads. Standards are good, but many standards are not necessarily better. Most of our Swedish, German and British built locos are built with Whitworth standard threads, but there are exceptions. And these days, BSW screws are hardly obtainable in Sweden, only UNC. https://en.wikipedia.org/wiki/Östra_Södermanlands_Järnväg Right now I have one odd problem. In the machinery of our two Swedish built superheated 2-6-2T Nos. 4 & 9 there are fitted screws for the bearings of the coupling and side rods. As you may see in the detail of the drawing below these are mostly 3/4" fine treads with Whitworth profile. But the odd thing is that they are 14 TPI!!! As we know 3/4" BSF is 12 TPI and UNF is 16 TPI. The Motala variety is right in between. No. 4 is in reasonably good shape but No. 9 is in need for a number of new screws, some of them have been replaced by plain W3/4" by the previous owner. When I Googled for such threads I came across references to the "Admiralty Fine Threads" which happens to be 14 TPI for 3/4". Does this standard exist today and are taps and dies available anywhere? The alternative is of course to have these tools custom made. I found a few companies that claim they make such tools, but is there any one you would recommend?