On 05/05/2020 20:13, AnthonyL wrote:
I hurriedly bought a pump some years back and have never been able to
use it.

https://www.flickr.com/photos/79018230@N05/49860238831

It has an external thread so I guess something is supposed to fasten
on to it.

I've put a standard Schrader/Presta adapter alongside for scale
purposes only. The pump has no internal thread(s).

I think you have bits missing. There should be a sort of "nut" that goes
on the external thread, except that it has an internal flange. There
should be a rubber component that fits inside the bit with the threads
on. This should have a hole about 6mm diameter that a normal "high
pressure" bike tyre valve fits into. When you tighten the "nut" it
compresses the rubber bush so that it grips the valve and provides a seal.