What bicycle(?) pump is this?

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.

A bit like this

Is there a name or do you have any link as I can't at the moment find anything? Though probably not worth the effort. What's the advantage of designing it that way?

Here is a video of a similar pump in use

No but another poster has already spotted it. If this were mine I would be checking whether this is a standard thread, for example it might well be a BSP as used on plumbing fittings. So you might find that one of the nuts off a compression fitting would fit, then I would see if I had a bit of spongy rubber from which I could make the "washer" bit. I have some foamed EVA about 12mm and 18mm thick that might do the job. Or you could cast some "plumbing" silicone in the space, with a suitable bit of stick where the valve should go. But you would have to decide how much your time is worth. Another possibility might be to "glue in" one of the flexible hoses to suit your bike valve. I'd probably use epoxy, but if you can find a nut about the right size then hot melt glue could work as well (relying on the nut to stop it being forced out by the gas pressure).

Got it thanks. Someone must have pinched the nut before I bought it and the last time I had bought a pump would have been when Dunlop valves were the norm and there was a 6" tube adapter that pushed down the middle of the pump handle.

I've since bought a mini-pump but the "nut" fits inside. And now I discover that the old fashioned pump would have worked fine!

I thought it looked 'ok' from the pic but wasn't sure if you had lost the runner insert?

And you know the idea of that pump is that it mounts inside the frame, in front of the seat post (I think).

Cheers, T i m

I've always wondered why this sort of pump with no flexible hose from pump to valve has become so popular. The ones with a flexible hose allow for a bit of movement of the pump as you are operating it, without flexing the valve stem on the wheel. The "tubeless" ones don't have that flexibility, so as you work the pump you strain the valve stem unless you take great pains to brace the pump against the spokes of the wheel - and that probably doesn't do them any good.

I wish *all* bikes had Schrader (car tyre) valves. I know why a lot of modern bikes have Presta instead, because those are narrower and can fit through a smaller hole in the wheel, but Prestas are a PITA because you have to loosen the screw to pump the tyre up and then remember to tighten it afterwards, and a lot of air seems to leak out while the valve is in the "delicate" inflation state. And you have to remember to carry a Schrader to Presta adaptor (and not lose it at the bottom of a saddle bag) in order to use a pump for car tyres - I mean a foot-pump, not one of the high-pressure airlines at garages which say "not for bicycles". When I did a lot of cycling I carried a car foot-pump in my saddle bag because it was a lot quicker to pump up a tyre with a slow puncture than using a normal bike hand-pump.

Usually there's a locking lever, your photo doesn't appear to show one?

There isn't one, nor any apparent provision for one.

Thanks. Since when did a pump get so complex?

I know this is DIY but ...

You do know I am an engineer, don't you :-)

I have seen both sorts. The "nut" lets you adjust the compression on the rubber to compensate for wear.

Not on this version there isn't.

My track pump has one

but the one I travel about with doesn't

Note :- the small hand pump can do high volume OR high pressure, middle length of barrel can be opened to allow greater `volume or fitted inside greater diameter barrel to allow higher pressure to be applied . I have never actually used this feature (bit gimicky for my taste but it was cheap and was available when the other more expensive 'wee' pump broke whilst I was out on a ride). The 'wee' pump has no pressure gauge so it is pretty much pump until tyres are hard job. Then if greater accuracy is required the big pump is used when I get home