Reference:Movements: Difference between revisions

This Aegler-supplied 10½-ligne hand-wound family uses the 700/710 architecture. It has a straight-line lever escapement, monometallic Superbalance adjusted to six positions, self-compensating Breguet balance spring, and swan-neck micrometer regulator, with no documented shock protection. Antiquorum names Cal. 700 in its catalogue for ref. [[Reference:3358|3358]], case 51,419, with 18 jewels; its ref. [[Reference:2081|2081]] case 599,744 lot names the same caliber and grade but records 15 jewels. The discrepancy is unresolved, so the jewel count is left unspecified here. [https://catalog.antiquorum.swiss/en/lots/rolex-lot-108-225 Antiquorum, ref. 3358] [https://catalog.antiquorum.swiss/en/lots/rolex-lot-108-226 Antiquorum, ref. 2081] The movement powers the original Air-King 4925 and its Air-Lion, Air-Tiger, and Air-Giant siblings, including the sub-seconds 4365, mid-size 4444, and 4647 Hunter Precision. Its architecture links the pre-war Prince and Bubbleback movements with the post-war automatic Cal. 1030. Cal. 700 and 710 are hand-wound movements; Cal. 720 belongs to the automatic branch. White’s *The Vintage Rolex Field Manual* maps [[Reference:5031|ref. 5031]] to Cal. 710 in a reference table, but auction catalogues describe 5031 examples as automatic date watches. Christie’s [https://www.christies.com/en/lot/lot-204100 listing] records movement number 37519 but no caliber; Antiquorum’s [https://catalog.antiquorum.swiss/en/lots/rolex-lot-120-203 1995], [https://catalog.antiquorum.swiss/en/lots/rolex-lot-53-191 1999] and [https://catalog.antiquorum.swiss/en/lots/rolex-lot-222-285 2009] entries do not name a caliber and report differing sizes and jewel counts. Sotheby’s 2020 and 2022 entries say only “automatic.” The available records do not resolve the conflict, so the 5031 is not assigned to Cal. 710, A.295, 740, or 745 here.

Catalogues describe hand-wound Kew A movements in refs. [[Reference:5056|5056]] and [[Reference:6210|6210]] as 10.5-ligne or Cal. 720 examples; Uhrenkosmos calls the 6210 Cal. 700. Bonhams describes ref. 5056 movement 4215 as a Cal. 700 base reworked into what Rolex called Cal. 720, and Vetroplastica describes the Kew movement as Cal. 700-based with Cal. 720 parts. These are source-specific labels for manual Kew A movements. The generic Cal. 720 entry above describes the automatic branch. [https://www.bonhams.com/auction/24632/lot/21/rolex-a-very-rare-stainless-steel-manual-wind-bracelet-watch-with-kew-certification-and-especially-good-result-oyster-speedking-kew-a-certificate-ref-5056-circa-1947/ Bonhams, ref. 5056] [https://www.christies.com/en/lot/lot-5257637 Christie’s, ref. 6210] [https://www.bonhams.com/auction/29155/lot/19/rolex-an-extremely-rare-18k-gold-kew-a-manual-wind-wristwatch-rolex-oyster-observatory-chronometer-ref-6210-circa-1955/ Bonhams, ref. 6210] [https://www.vetroplastica.it/rolex-kew-a-18.html Vetroplastica] [https://www.uhrenkosmos.com/rolex-meilensteine-1952-bis-1955-wegweisend/ Uhrenkosmos]

The pallet fork runs in jewels, while the escape wheel has shock-mounted settings and cap jewels on both pivots, matching the treatment of the balance. Indirect centre seconds, driven from the fourth wheel through a friction-sprung pinion, can produce seconds-hand flutter even in a healthy movement. The earliest examples may lack shock protection; Antiquorum's 1946 ref. 4560 description names none.

<span id="cal-1215"></span>

Cal. 1570 is the 19,800-vph revision of the 1560, introduced in 1965. Christie’s identifies Cal. 1570 in ref. 1011 case 692498, dated circa 1962; its lot chronology overlaps the ref. 1011 Cal. 1560 examples and does not establish a changeover. See [[Reference:1011|ref. 1011]]. One Artcurial ref. 1005 lot is catalogued with Cal. 1550, despite a chronometer-dial description; other 1005 catalogues list 1560 or 1570. This single lot does not establish a 1005 movement variant or resolve whether the movement is original. It retains the free-sprung Breguet overcoil and Microstella regulation, with adjustment to temperature and five positions. Family-wide bridge engraving causes date movements such as the 1575 in a ref. 1665 to appear marked 1570; the engraving alone does not identify the exact caliber. Phillips identifies Cal. 1570 in a circa-1985 ref. 1024, while Dorotheum lists it on a circa-1965/70 example; those ref. 1024 dates overlap its Cal. 1560 records. Christie’s, Antiquorum, Phillips, Dorotheum and Bonhams also catalogue Cal. 1570 in ref. 1501 examples; see [[Reference:1501|ref. 1501]]. These lot labels do not establish a 1501 changeover year.

The balance has four Microstella screws in two opposing pairs, not two. Rolex required equal adjustment within each pair to preserve poise. The larger pair changes rate by about two seconds per day and the smaller by about one. On this family the screws sit in the balance rim; the later 3135 platform moves its Microstella nuts to the inner rim.

== Sources ==

* [https://www.christies.com/lot/rolex-a-rare-stainless-steel-automatic-wristwatch-6139178/?intObjectID=6139178&lid=1 Christie’s, ref. 6556, case 138'822, Cal. 1040]

* [https://www.hodinkee.com/articles/the-restoration-of-a-rolex-tru-beat-caliber-1040-reference-6556 Aaron Berlow, Cal. 1040 restoration, Hodinkee, 2015]

* [https://www.clubderelojeria.com/comunicaciones/R/ROLEX/rolex1575/ROLEX%201575.pdf Rolex Cal. 1575 parts catalogue, Rolex technical department]

* [https://www.phillips.com/detail/rolex/HK080319/903 Phillips, HK Auction NINE lot 903, exterior ref. 6558 / inner stamp 6556, Cal. 1040]