Glossary · Regulation
Breguet overcoil
A hairspring whose outer turn is raised and curved over the body of the spring.
Explanation
An overcoil (Breguet) hairspring has its outer turn raised and curved inward over the plane of the spiral. The terminal curve makes the spring breathe concentrically as it opens and closes, reducing pivot side-pressure and improving positional rates. Hand-forming an overcoil is skilled work; its presence is a traditional sign of a quality movement.
In the object catalogue
Catalogued objects whose own source record mentions “Breguet overcoil”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.
Component
Elgin No. 239 Veritas Hairspring and Balance Assembly
“This horological component comprises the hairspring and balance assembly identified by the source as originating from an Elgin No. 239 Veritas pocket watch movement. The source …”
Pocket watch
C. Dégallier and Ch. Grottendieck hunting case pocket watch
“This hunting case pocket watch, manufactured in Switzerland circa 1900, features a 750-grade yellow gold case and a gold cuvette. The watch is signed by the Swiss manufacturer C…”
Pocket watch
Dual time zone pocket watch with split-center seconds
“Balance spring: Blued steel Breguet overcoil”
Pocket watch
Jules Jurgensen Minute Repeating Chronograph
“This Jules Jurgensen pocket watch, serial number 14338, is a minute-repeating keyless chronograph crafted in 18k pink gold. The watch is housed in a four-body polished "bassine …”
Pocket watch
J. Ullmann & Co. Quarter-Repeating Pocket Watch
“This J. Ullmann & Co. quarter-repeating pocket watch, identified by movement number 17747 and case number 156, dates to approximately 1890. The firm maintained operations in La …”
Wristwatch
Omega Observatory Tourbillon Wrist Chronometer
“This Omega wrist chronometer, numbered 10595936, is built with a Caliber 30 I movement, which was one of 12 produced in 1947 for Geneva Observatory trials. The movement particip…”