Glossary · Mechanism
Hacking mechanism (seconds stop)
A mechanism that stops the balance when the crown is pulled to set the hands, allowing precise time synchronisation.
Explanation
A hacking (seconds stop) mechanism halts the balance when the crown is pulled to setting position, so the watch can be synchronised to a time signal to the exact second. Standard on military watches from the mid-20th century — hence 'hack watch' — it is now normal on most mechanical movements.
In the object catalogue
Catalogued objects whose own source record mentions “Hacking mechanism (seconds stop)”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.
Pocket watch
Hamilton 4992B 24-Hour Military Pocket Watch
“This Hamilton 4992B is a 16-size, 22-jewel military pocket watch dated circa 1941 by the seller and manufactured for the United States Government during World War II. Housed in …”
Pocket watch
Hamilton 4992B 24-Hour Military Pocket Watch
“This Hamilton 4992B open face military pocket watch dates to circa 1941, produced for the US Government during World War II. The dealer reports a size 16s nickel three-quarter p…”
Wristwatch
Bifora Unima Chronometer wristwatch, reference 4499
“According to the seller, this vintage German chronometer wristwatch by Bifora, reference 4499, dates from the late 1950s. The 35 mm stainless steel round case houses a manual-wi…”
Wristwatch
A. Lange & Söhne B-Uhr Observation Watch
“This military observation watch, designated B-Uhr (Beobachtungsuhr), originates from the period of the Second World War. It was produced by the German manufacturer A. Lange & Sö…”