Lift angle

A timing machine does not watch the balance; it listens to the escapement. To turn the sounds it hears into a figure for the balance's amplitude it must know, or measure, how much of the swing the escapement itself drives, the lift angle. Witschi Electronic, a Swiss maker of watch testing instruments, specifies for its WisioScope the "Determination of actual lift angle and actual amplitude, independent of lift angle", the "Measurement of the real lift angle or manual input", and a range of "Lift angle 10 to 90° adjustable". Witschi is cited here only as a manufacturer describing its own instrument, which is what a timing machine expects to be told.

No issuing authority defining the term was found. The Federation of the Swiss Watch Industry publishes the list of available NIHS norms for the Swiss watch industry, in the edition valid from April 2026; it contains no entry whose title includes angle de levée. ISO's horological vocabulary does exist: ISO 6426-1:1982, Horological vocabulary — Part 1: Technical and scientific definitions, edition 1, published February 1982 and still listed by ISO as Published, but ISO's catalogue page says only that it gives 20 definitions, and the text is paywalled, so whether lift angle is among them has not been established.

What this Codex does not do: quote a definition, or give a lift angle for any calibre. In practice the figure is supplied per movement by its maker, and the only published bound found here is an instrument maker's own adjustment range of 10° to 90°. Until a standards body, a metrology institute or a learned society is found to define the angle, this entry records it as a term in universal workshop use with no authoritative definition traced.