Full teardown of a Rolex Submariner Date on the bench today, powered by the legendary Calibre 3135.

Introduced in 1988 and serving for over three decades, the 3135 is widely regarded by watchmakers as one of the most robust, serviceable automatic calibers ever produced. It’s not over-complicated for the sake of it—it’s designed strictly for longevity, stability, and serviceability.

A few favorite engineering highlights while laying this one out:

• The Balance Bridge: Unlike a standard cantilever balance cock, the 3135 uses a full balance bridge anchored on both sides, allowing rigid stability and precise microstella regulation of the free-sprung balance.
• The Purple Reversing Wheels: The signature anodized Teflon (PTFE) coated gears in the automatic module that ensure smooth, quiet bi-directional winding without requiring heavy lubrication that can breakdown over time.
• Instantaneous Date Jump: The cam and jewel mechanism under the dial work provides that crisp, unmistakable midnight date snap.

Every single screw and wheel has been inspected, run through multi-stage ultrasonic baths, reassembled with Moebius synthetics, and regulated back to chronometer spec.

Always a treat to work on a movement that was truly engineered to be rebuilt for generations.

The Watchmakers App now offers a full digital dictionary of the universal Swiss watch-parts numbering system. Over 1,500 standardized watch-part numbers, organized into categories and linked to the calibers that use them, now available free on iPhone, iPad and Android.

What it is

In 1948 Ebauches SA introduced a universal numbering system for mechanical watch parts, and it became the most widely used way to identify them. A plate is #100, a barrel bridge #105, a train wheel bridge #110 and a mainspring #770. The same numbers appear on material-house listings, parts envelopes and manufacturers' technical sheets around the world. Another 10-digit system was introduced in 1976, but the quartz crisis meant the newer system was much less widely used. The original numbers are still the everyday language of vintage watch repair.

Swiss part numbers put more than 1,500 of these numbers into one searchable reference. Each number has its standard description. Entries are grouped into categories that follow the original dictionaries, from Frame and barrel, Wheels and pinions and Swiss lever escapement to Hairsprings, Mainsprings, Hands, Crystals and Screws. There are also special-materials groups for self-winding watches, calendars and moon phases, chronographs, alarm watches, and electric/electronic watches.

The dictionary was compiled from the primary Ebauches SA references:

• A New Standard Technological Dictionary of Watch Parts (1948)
• The revised 2nd edition (1953)
• Dictionnaire Horloger, Terminologie Numérotation (1976) and its 1988 supplement from ETA SA

These were cross-checked against watch material houses' listings and manufacturers' technical sheets.

How it's used

In practice, a watchmaker holding an envelope marked "#401" can find out in seconds that it holds a winding stem and see which movements use it. Someone restoring a movement can go the other way, from a caliber's parts list to the standard number to quote to a supplier or create a query for eBay search.

About The Watchmakers App

The Watchmakers App brings together caliber data from original Ranfft, different watch material houses, manufacturers' technical sheets and historical catalogues in one reference for watchmakers, restorers and collectors. It covers calibers from 340 manufacturers, with technical specifications, images and parts interchangeability data. You can identify a caliber with detailed search filters or from a photo, and keep a list of favorite calibers. It also includes reference sections for Swiss part numbers, U.S. import codes and trade marks.

The Watchmakers App is available for free on iPhone, iPad and Android, while some advanced features are available behind paid subscriptions (with 2 weeks free trial), majority of data is available for free. The app and its data are updated regularly - don't forget to enable automatic updates on your device to always have the latest version and information. For more information visit https://thewatchmakersapp.com website.