Here is a slightly baffling one to identify

Does anyone recognize this three button chrono please? Completely unmarked anywhere. From materials, looks like high quality movement with kinda average finished-chrono parts kinda average finished-off.

My problem is that the winder is totally jammed, it won't pull out to set, and looks so worn out that all knurling have come off it. The watch has just been serviced and works fine as do all three pushers. It is pretty much exactly 30mm across the movement

Anyone got any ideas as to where I might find another one?

I know this watch is rare and my repairer was surprised to see those three pushers but annoyingly, i think I have another exactly like this in my collection and as I remember it, that one has no markings anywhere either

Interesting: Yes, the Landeron 47 seems to be the one (though there are lots of erudite looking references on line to the 47 being a two button configuration) and curiously, most of the ones shown anywhere on line are almost completely unmarked: The ones which are marked have unrecognisable names on the dial or different names on the dial and movement. I wonder why this three-button configuration was so often unmarked?

They really are very similar indeed, aren't they? The differences seem to show that these two pics are the same watch in the same size in different stages of operation.

In fact the 1937-70 calibre 48 (apparently produced by the million) looks like just a development of the comparatively rare 1937 calibre 47.

Curiously, Ranfft also shows both the two button and three looking very similar indeed.

That was what led me to wonder whether this watch with three buttons is in fact a 47. Maybe by 1938 someone decided that no one wanted three buttons? (or they were produced for some specific purpose?)