Following on from the DSG one, the one presented here (metric only) is clever:

https://www.ernault.com/cat_view/2-documentations-techniques-technical-documentation/4-jupiter-catalogue-ancien/16-jupiter-h-trainard

(you need JUPITER – H – PL46 – APPAREIL A RETOMBEE DANS LA PAS)

If it is not obvious, gears 100 and 114 have the same number of teeth. The 66t and 70t gear would need to be cut at the same pitch diameter (probably that of a 68t gear).

A 66t gear has factors of 2, 3, 11 (the 11 is for for 5.5mm or 11mm pitch threads). A 70t gear has factors of 2, 5 and 7 (the 5 is for 1.25mm and 2.5mm pitch threads; 7 is for 1.75mm and 3.5mm pitch threads).

Assuming a standard 6mm pitch leadscrew, items 107 and 108 (double-sided) make sense (6 = 2 x 3, 11, 14 = 2 x 7, 10 = 2 x 5). Item 108 (17 divisions) baffles me completely. I could understand 16 divisions (4 x 4 for 8mm pitch but 17 is a prime number.

I think the company is this one:

https://www.somab.fr/en/pages/historique-hes-ernault-somua/

Years ago John Stevenson mentioned a Russian lathe he had seen with interchangeable dials on the thread indicator and this is the only one I have ever seen close to that.