Glossary · Mechanism
Third wheel
The going-train wheel positioned between the center wheel and the fourth wheel.
Explanation
The third wheel is the train wheel between the centre wheel and the fourth wheel. It transmits power and helps set the overall gearing ratio. It has no hand of its own in a conventional layout, but in some indirect-seconds or off-centre designs its position changes. Its pivots should be checked for wear and correct end shake during service.
In the object catalogue
Catalogued objects whose own source record mentions “Third wheel”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.
Pocket watch
Louis Richard Triple Detent Constant Force One Minute Tourbillon Chronometer Pocket Watch
“This 18k yellow gold pocket watch chronometer by Louis Richard dates to circa 1860 and measures 56 mm in diameter. According to Phillips, the manual-wind movement bears number 1…”
Pocket watch
Hamilton Model 3992B Deck Watch
“This Hamilton open-face deck watch features a damascened nickel movement marked calibre 3992 B with 22 jewels, adjusted for temperature and six positions. The movement carries s…”
Movement
Joseph Preston lever watch movement ébauche
“This English full-plate watch movement ébauche was made in Prescot by Joseph Preston, dated circa 1860 (or late 19th to early 20th century in museum notes). Designed for a lever…”
Pocket watch
Open-face 18 ct. gold fusee lever pocket watch
“This is a full plate undersprung fusee lever pocket watch, held in the Auckland Museum Tāmaki Paenga Hira collection. It is constructed with a heavy open-faced 18 ct. gold case,…”
Movement
Movement of a gentleman's watch
“Visible central wheel, third wheel, and fourth wheel assemblies”