That is excellent Deejay and willingworker, well done. A point of caution: be very careful finding a screw that actually fits that center thread. It might not only be Whitworth, which is interchangeable with UNC in all sizes except half inch (minor difference in thread angle, not usually necessary to worry about in low stress applications), but it could be BSF, or even BA, both of which are very rare these days. It seems unlikely to be either metric or one of the American threads, but anomalies do happen. The main point is that the right screw needs to be found, and it may well be something extremely unusual. Just finding a screw of the right diameter and screwing it in will simply ruin something rare, perhaps almost irreplaceable.
When the right screw is found, please post details here since it will be useful for the archive.
