Glossary

Diameter

In addition to the standard diameter measured in French lignes or US sizes, diameters are also provided in millimeters (mm):

D: Undefined value obtained from public sources.
Dn: The nominal diameter, derived either from lignes or the US size. When derived from lignes, it typically represents the maximum mounting diameter. In contrast, the US size often signifies the outer diameter.
Dm: The mounting diameter, ensuring the movement fits into the case or mounting frame. This is slightly smaller than Dn.
Do: The outer diameter, which is the largest. Many movements have a flange slightly larger than Dm, providing support on the case band or mounting frame.

For irregularly shaped calibers, two dimensions are typically recorded. US sizes are more precise due to the standardization of US movements and cases to a certain extent.
Ligne-based diameters are often used for promotional purposes: smaller movements might be presented as even smaller, while larger ones might be depicted as even bigger. Provided Do exceeds the manufacturer's specifications and Dm is smaller, the manufacturer's details are adhered to here. If the discrepancy is less than 0.25", these details are retained. Greater variances see the actual measurements rounded to the nearest 0.25" step.

Height

This is typically the construction height, denoting the distance between the surface upon which the dial rests and the highest component on the rear, such as plates, bridges, cocks, or the rotor for automatic movements. Components like screw heads, settings, and regulators are excluded as they can be adjusted. If elements like winding gears or rotor bearings extend beyond this height, and the difference is significant, it's highlighted to ensure data comparability.

Power Reserve

Based on either published resources or personal measurements. The value is rounded down to the nearest hour, and considering individual variations, an additional hour is deducted. Only well-maintained, original movements are used for these measurements. When multiple such movements are studied, the lowest rounded power reserve is noted.

Balance Staff / Stem

Here the Flume order numbers are provided, and occasionally numbers from other sources. These numbers, combined with a search function, aid in identifying similar donor movements.

Mainspring / Battery

For mechanical timepieces, the mainspring's description is provided, led by the Flume number (Zf....) representing a standard spring with an end hook. This is followed by dimensions listed as width, inner barrel diameter, strength, and length. Missing Flume numbers signify non-standard springs or those with special terminals. For electronic watches, battery details or other pertinent information are provided.

Further Data

Our archive is consistently updated to include more data. Currently, the following data is available:

F: Mounting height - the distance between the dial plane and the mounting flange.
T: Stem height - the gap between the dial plane and the stem center.
Hands: The diameters of the hand holes, beginning with the slowest (usually the hour hand) and ending with the quickest (typically the second hand). Main hands and sub-dial hands are divided by a slash.

Note: Movements with display discs on the dial side (e.g., calendars) sometimes lack dial support. In such cases, the disc's surface acts as the reference for H, F, and T. If the movement comes with a temporary dial spacer, its additional height is also mentioned.