Thales Model A
Back when I was working in Brussels, I saw a small advert online, offering a mechanical calculator for sale. The picture was a bit puzzling, as it didn't include any means to identify the machine - no logo, no lettering, just a very small vendor's plaque on the baseboard. I stole some time away from my employer, and drove down to a small village near Namur. The vendor showed me the machine, it looked very good, and indeed did not contain any markings identifying it. The serial number, however, (5616) was prominently visible.
Puzzled, I bought the machine, and took it home, as it did remind me of something I couldn't quite put my finger on.
Back home, I started comparing it with machines I had, and the size and shape of the machine itself, the baseboard, the location of the serial number, and everything else in its appearance and behaviour classified it as a Thales A. Only it didn't bear the Thales trademark on the top cover. Close inspection revealed that the word "Thales" had been ground off the top cover (there's a slight depression), and the whole machine had been cleanly repainted. It was probably a trade-in against a newer machine in a shop carrying a rival brand (according to the plate on the base, "Burma", Ste. de Machines de Bureaux", Dageleer Frères & van Campenhoudt, 34 Rue Montagne aux Herbes Potagères, Bruxelles") that was "reconditioned" and anonymized, and then sold second-hand.
Mystery solved on the one-but-most puzzling purchases I've ever made!
Here are some pictures of an undisguised slightly later Thales A (N° 6016, exactly 400 machines later), with the larger tabulating carriage lock with the metal "snap-back" band installed.
And finally, both machines together:
