0007  Tell

25 Oct 2026: chosen as a practice movement, since it is missing its hands and crystal. It is manual-wind with a date mechanism, so it also gives practice on the calendar work. Dial removed, movement close-ups taken. Plate is stamped 'SEVENTEEN 17 JEWELS' and 'SWISS'; '96-4' is stamped near the balance, beside a small oval logo with letters 'ST' (a stylised FHF/ST mark, reading unsure). Regulator has a +/- scale. This matches the Fontainemelon (FHF/ST) calibre 96 family: 11.5 ligne (about 26 mm), 17 jewels, 18,000 bph, manual-wind, Incabloc, launched 1965, with 964 listed as a variant. Probable but not confirmed; check the diameter against 26 mm and compare the layout with a reference photo. Ranfft does not list a date mechanism for the base calibre 96, so the date on this watch needs checking on the dial side of the movement. A small hooked metal part fell out when the dial was removed (roughly 4-5 mm long, curved hook at one end and a thin straight arm; its function is not identified). Keep it in a labelled bag with this watch. Source: https://ranfft.org/caliber/5786-FHF-96 Dial-side photo. A white date disc numbered 1-31 sits over a calendar mechanism on the dial side, with a date driving wheel, intermediate wheels and a spring lever (jumper) at the lower right. This looks like a calendar module added on top of the base movement, which would explain why the base FHF 96 is not listed with a date; unconfirmed. Calibre remains probable. The hooked part that fell out could be a calendar spring or lever (unconfirmed); check for a post or pivot with no part on it. Service article on the FHF ST 96-4 (Alan Krantas, Medium): 25.6 mm, 4.6 mm high, 17 jewels, 18,000 bph, date only with no quickset (advance the date by turning the hands between about 21:00 and 00:00), no hacking, about 48 hour reserve. This corrects my earlier idea that the date was an add-on module; it is part of the calibre. Points from the article for a teardown: the date disc is held by three small plates, the longest also covers the date jumper and its spring (at 6 o'clock); the date driving wheel carries an elastic metal date finger; the crown wheel screw has a reverse thread and a washer; the click spring and setting lever spring are easy to lose; the dial-side shock jewel setting is smaller than the one in the balance bridge. The hooked part that fell out may be the date finger or a calendar spring (unconfirmed). Source: https://alankrantas.medium.com/servicing-a-fhf-st-96-4-manual-winding-movement-a-steady-echo-from-the-past-60c3f6257f05 Crystal seat measured around 30.8 mm (a second reading of 30.6 mm was possible from the photo, so unconfirmed); ordered a 30.8 mm and a 31.0 mm low dome acrylic to find the best fit. Order 02-15357-71912, delivery estimated 28-29 Oct. Original crystal shape (flat or domed) unknown. Press-fit with a crystal press; if it needs heavy force, try the smaller size. Source: https://www.ebay.co.uk/itm/196361689495