The cheapest imperial micrometer I found is still a bit too much for me,
so I've ordered a Moore & Wright Metric & Imperial Vernier Caliper for just under £18.
It's supposed to be decent quality and accurate enough for a Chinese made tool... ???

measures to a thousandth of an inch.

It's 40 years since I last used anything like a slide rule,
... when it's delivered, let's see if I can get on with it, and if it does my intended job ok... ?????.