Disassembly

Disassembly is taught here as a sequence of reasoning, not as a step-by-step manual for working on a real watch — the goal is to understand what a trained watchmaker is doing and why, which is itself valuable independent of ever picking up tools. The guiding principle throughout is releasing stored energy and reducing tension before removing parts, in an order that never leaves a spring, lever or jewel unsupported under load.

A typical strip-down begins by removing the hands and dial (after first letting down the mainspring's power completely, a step covered separately, since disassembling a wound movement risks a sudden and damaging release of energy). With the dial off, the keyless and motion work on the dial side are removed first, since they are independent of the going train and provide an easy, low-risk starting point for handling tiny screws and levers.

Attention then moves to the top-plate side: the balance and its cock are removed first, both because the balance is the most fragile and valuable component (a bent hairspring or a chipped balance staff pivot can be effectively unrepairable outside specialist work) and because removing it first eliminates any residual drive to the escapement, making the rest of the strip safer. The pallet fork and its bridge come next, followed by the train bridge and the wheels themselves, generally from the escape wheel backward to the barrel, though conventions vary between calibres and manufacturer service manuals.

The barrel itself requires particular care: a mainspring under tension inside a closed barrel is a genuine hazard to fingers and eyes if the barrel is opened incorrectly, and mainspring winders or specific technique are used to control the release. This is one of several points in a real service where inexperienced handling causes not just cosmetic damage but a real risk of injury, which is one reason professional training includes supervised repetition long before a trainee works on a client's watch unsupervised.

Every part removed is conventionally placed in a numbered or ordered tray, in the reverse of the order it will be reassembled, and photographed or diagrammed if the calibre is unfamiliar — because reassembly errors (a wheel installed with the wrong end up, a spring under the wrong tension) are far more commonly the source of a 'ruined' watch than any single disassembly mistake. The overall lesson to take from this sequence is that competent disassembly is really an exercise in sequencing and energy management, and that is exactly why it takes supervised practice to do reliably on real, valuable movements.