Quick references we get asked for most often. Need something specific to your watch? Ask us with the calibre and case reference.
Common movement sizes
- Seiko NH35 / NH36 / 4R36 — ø27.4mm (12½″), height 5.32mm, date/day-date, hacking & hand-wind.
- ETA 2824-2 / Sellita SW200-1 — ø25.6mm (11½″), height 4.6mm, the workhorse automatic.
- Miyota 9015 — ø26.0mm, height 3.9mm, thin automatic.
- Unitas 6497 / 6498 — ø36.6mm (16½″), hand-wind, small seconds at 9 or 6.
- Valjoux 7750 — ø30.0mm (13¼″), height 7.9mm, automatic chronograph.
Crystals
- Measure the seat diameter, not the outside of the bezel. Sapphire is usually a press fit into a tension ring or gasket.
- Flat for tool and dress watches; domed and double-domed for vintage looks. Watch for internal AR coating — it changes reflection colour.
- Acrylic (Hesalite) can be sized and polished; sapphire cannot.
Lug width & straps
- Lug width is the gap between the lugs in millimetres — common sizes are 18, 19, 20, 21 and 22mm.
- Spring bars: standard ø1.5mm/ø1.78mm tips; dive and tool watches often use ø2.0mm “fat bars”. Curved bars are needed for some integrated cases.
- Taper (e.g. 20→16mm) is the width at the lugs vs the buckle.
Water resistance
- Ratings assume new gaskets. After any case work, pressure test before the watch goes near water.
- 3 ATM splashes only; 5 ATM hand washing; 10 ATM swimming; 20 ATM+ diving.
Lubrication, in short
Moebius 9010 for fast-moving jewelled bearings, HP-1300 for slow trains and motion work, 8200 for the mainspring in hand-wind barrels, 9504 grease for keyless works, pallet stones and high-friction points. Declarations and safety data are on the Company Documents page.