Nick C
Thanks all. I did try to make sure I didn’t twist it as I took it off the Hornby axle. I’ll try using a file to replicate the knurling, though I suspect the gap will be too big for that to work. Looking again at the original axles, there’s a noticeable step at the ends, at the inner end of the knurled bit the wheels sit on, presumably to aid assembly in the factory.