Mechanism · A spring, released at a controlled rate
The mechanical movement
Six specifications separate a fine movement from an ordinary one, and only two of them appear in the advertising.
The path of the energy
A mainspring coiled in a barrel, wound by hand or by a rotor. A gear train stepping the energy down and driving the hands. An escapement releasing the train one step at a time, which is the ticking. A balance wheel and hairspring oscillating at a fixed frequency, which decides the accuracy. Jewels as low friction bearings at the points of highest wear. Everything else in horology is refinement of those five things.
Finishing, where the money is
Two movements with identical specifications can differ tenfold in price, and nearly all of it is finishing. Anglage, the hand bevelling of bridge edges to a mirror polish. Black polishing on steel. Perlage and stripes. None of it improves timekeeping. The tell for hand work is the interior angle: a sharp inside corner on a bevel can only be cut by hand, and a rounded one came off a machine.
Free sprung, and why it matters
Most movements regulate the rate with an index that changes the effective length of the hairspring. A free sprung balance regulates with weights on the balance wheel itself instead, which is harder to manufacture, more stable over time and less likely to be knocked out of adjustment. It is one of the genuine markers of a serious movement and it is visible through a display back.
In house, honestly
A movement made by the selling brand carries a premium. Manufacturing capability is genuinely difficult, and the outcome for an owner is accuracy, reliability and serviceability. The widely supplied workhorse movements score extremely well on all three, are understood by every watchmaker in the world and are cheap to service. A house movement may be finer and may also mean a five week wait and a return to the manufacturer for everything.
Beat rate, and what it costs
Higher is not better. It is a trade between stability and wear.
How to check it
- Look through the caseback at an interior angle on a bridge. Sharp means hand finished.
- Check whether screw heads are polished and their slots aligned. Nobody aligns slots on a movement they are rushing.
- Look for a free sprung balance, with adjustment weights on the rim rather than an index arm.
- Ask about parts availability to independent watchmakers before buying. In twenty years it will matter more than the finishing.
Care
- Have the amplitude measured rather than servicing on a calendar. Falling amplitude is the early warning.
- If a watch suddenly gains minutes a day, it is magnetised. Demagnetising takes seconds and costs almost nothing.
- Instruct in writing: do not polish the case, and return the replaced parts.
- Wind a hand wound watch at the same time each day, and stop at the first resistance.
- A winder is only useful for a calendar watch worn rarely. A movement does not deteriorate from standing still.