Reference:Movements: Difference between revisions

<div class="rp-era"><div class="rp-era-name">Bubbleback / early automatic</div><div class="rp-chips">[[#cal-520|520]] [[#cal-620|620]] [[#cal-600|600]] [[#cal-a260|A260]] [[#cal-a296|A296]] [[#cal-645|645]] [[#cal-740|740]] [[#cal-745|745]]</div></div>

Cal. 300 is the original Prince movement, made from 1928 to 1935. Rolex's factory caliber table places it under the "T.S." size code shared by Cal. 310 and Cal. 350. Christie's describes all three as the same movement base, with interchangeable parts and the balance bridge identifying the original execution. Prima movements have 15 jewels and six-position adjustment; Extra Prima and Ultra Prima versions have 18 jewels, six-position adjustment, and sometimes a Chronometer marking. David Boettcher identifies the additional jewels as two end-stones on the escape-wheel pivots and a top bearing on the centre wheel. Early movements carry the grade wording on the ratchet wheel, while later examples place it on the main train bridge. The photographed Extra Prima, marked "Observatory 6 Positions," shows the later convention.

Cal. 300 has no shock protection, consistent with Incabloc reaching production only in 1938, after the core Prince design was established. Its winding-stem bridge is a known service weak point. A movement that sets the time and then disengages may have a broken bridge; watchmakers use aftermarket CNC-machined brass bridges and stems for this repair.

The architecture of Cal. 360 is disputed. Christie's describes a 1938 ref. 2835 "Prince Elegant" with a tonneau-shaped 15-jewel movement, and Charles Jarman's ''The Rolex Reference Guide'' (4th edition) calls Cal. 360 a manual, small-seconds, tonneau-shaped movement with a SuperBalance. Rolex's factory caliber table instead lists a rectangular 18-jewel Basic Caliber measuring 18 × 27mm, smaller than the Cal. 300 family's 16.9 × 32.7mm.

Both Jarman and the factory table date its introduction to 1937. The disagreement concerns its shape, size, and relationship to Cal. 300. The popular claim that "HW" means Hans Wilsdorf has no independent support; the factory table appears to give the size code as "F-LW," possibly an OCR rendering related to the "F" size-family code used for Cal. 180. Shigeharu Aritake's ''Rolex Scene 1913–1997'' is cited for a progression in which SuperBalance wording disappears from the winding wheel around 1938, but this does not resolve the architecture. Escapement and balance details remain unconfirmed.

The 1491 case is deeper than the 1490 to accommodate the jump-hour module. Case depth distinguishes a genuine 1491 from a 1490 fitted with a later module. Known service faults include a weak jump-impulse spring that causes a "lazy" disc advance, a worn retention pawl that makes the hour disc jitter, and a misaligned dial aperture that exposes parts of two numerals.

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. 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. Rolex's factory caliber table dates Cal. 700 and 710 to 1938. It lists Cal. 720 separately as an automatic movement with shock protection, not as a third member of this manual pair.

Auction catalogues describe compatible 10- to 10½-ligne manual movements in [[Reference:2765|2765]] and [[Reference:3009|3009]], but none of the surfaced records shows a Cal. 700 stamp. Both reference pages therefore treat the assignment as plausible rather than confirmed. The four documented [[Reference:1873|1873]] watches are also manual, but their catalogues name no caliber.

| 9&frac34; lignes / 21.7mm

| Not recorded &mdash; Cal. 620 derivative is straight-line lever

| Not recorded &mdash; Cal. 620 derivative is micrometer, later index

Rolex's factory table lists Cal. 600 as a Basic Caliber: manual wind, small seconds, 21.7mm, 17 jewels, entered in 1933 under a Hunter-patent size bracket. It is the root of the 9&frac34;-ligne automatic branch. Cal. 620 followed in 1936, with Cal. 635, 640, and 645 descending from that line in 1950. Both the factory table and Sotheby's Gleitze catalogue give 17 jewels.

The Gleitze case carries Glasgow import marks for 1926/1927, but its movement is later. Rolex's factory table dates Cal. 600 to 1933, and the stamped Super Balance refers to Aegler's Swiss patent CH196706, filed in August 1936 and granted in March 1938. The movement is a service replacement fitted at least a decade after the 1927 swim. A mid-1970s Rolex service box accompanied the watch. The case and engraving establish the watch's historical provenance; the present movement is a later replacement.

The escapement and regulator remain undocumented. Cal. 620, its immediate derivative, uses a straight-line lever and changes from a micrometer regulator to an index regulator, but those details cannot be assigned to Cal. 600 without direct evidence. Shock protection is more likely absent: the factory table flags it on the 1950 calibers in this branch but not on Cal. 600, whose design predates Incabloc production in 1938.

Made from 1952 to 1955, A296 powered the Big Crown 6200, early Explorers 6098, 6150 "Precision," 6298, and 6350, and early Datejusts 6104 and 6105. Its full rotor winds in one direction; it is not a bumper caliber. The 6150 and 6350 use the same movement in non-COSC and COSC forms. "A.296" is Rolex's size-family code and 775 its commercial number, so listings may use either designation for the same movement. Cal. 1030 replaced it in 1955 with bidirectional winding, a butterfly rotor, and a thinner automatic module. Phillips identifies that reduced thickness as the change that eliminated the domed Bubbleback caseback.

The movement has a straight-line lever escapement, monometallic balance, self-compensating Breguet balance spring, and index regulator. Catalogues using the commercial number 775 also specify six-position adjustment and a shock absorber, and Rolex's factory table marks ref. 775 as shock-protected. The two designations refer to the same build. The factory table also assigns A.296 to Cal. 765, showing that the size code covers more than one commercial caliber.

Christie's describes a 6150 balance as a "patented Super-balance," linking it to Aegler patent CH196706 and the recessed timing screws used on [[#cal-300|Cal. 300]]. Published jewel counts vary because some catalogues separate the going train from the automatic module. Figures of 18 and 19 appear for the base movement, with another two or seven assigned to the rotor module. One 6150 is described as a 19-jewel movement with a two-jewel automatic module. The factory table's figure of 18 counts the base plate alone.

Rolex's factory table gives the lineage as Cal. 600 to 635 to 645. It places Cal. 635, 640, and 645 under the A.260 size code at 26.4mm and 18 jewels, all entered in 1950 and all shock-protected. The shock system separates this 1950 A.260 group from the 1936 Cal. 620 base.

Antiquorum catalogued a subsidiary-seconds [[Reference:3599|ref. 3599]] as Cal. 635 with 19 jewels and described the caliber as 9¾ ligne, made from 1940 to 1951. Those details conflict with the factory-table size, jewel count, and 1950 entry above. Christie's also catalogued a visibly centre-seconds 3599 as Cal. 635, which conflicts with the caliber's small-seconds architecture. Without movement photographs, the Christie's caliber entry is best treated as a catalogue error rather than evidence for a centre-seconds Cal. 635.

Jewel counts also vary according to whether a catalogue includes the automatic module. Bonhams describes the related [[#cal-745|Cal. 745]] as "18 jewels plus 7 rotor jewels." Its 20-jewel description of a Cal. 645 in a 6085, against the factory table's 18, does not necessarily indicate a different movement.

The non-quickset date moves over roughly forty minutes and seats at the end of the change. A pawl on the calendar wheel engages a star wheel beneath the date disc before the jumper spring seats it. Rolex used the same arrangement in the 7xx, 1035 and 11xx families; instantaneous change arrived with the 1065/1066 and 15xx calibers. A date change beginning around 11:20 is normal for this mechanism.

Recurring service faults include worn pendant-tube and crown threads, winding stems and mainsprings, plus water-damaged date rings. The early Oysterdate calendar is the movement's weak point, though the pallet fork is fully polished and its jewels lightly undercut. Rolex service centres still accept these calibers; one 1974 example returned from overhaul running two seconds per day with a measured 57-hour reserve.

Produced from 1950 to 1962, Cal. 1030 was Rolex's first bidirectional and fully in-house automatic. Its 5.85mm profile ended the domed Bubbleback caseback, while the cutaway "butterfly" rotor stamped ROLEX PERPETUAL PATENTED is its clearest visual identifier. Finishing includes perlage on the rhodium-plated main plate, brushed bridges, polished screw heads and red anodized-aluminium reversing wheels. A conventional index regulates the movement; the visible regulator arm distinguishes it from the later free-sprung 1560 and 1570. Documented fitments include ref. 6098 from 1952, Submariners 6536, 6536-1 and 6538, Explorer 6610 and Air-King 6552. The same movement appeared in chronometer and non-chronometer watches.

Cal. 1530 ran from 1957 to 1965. Its 17-, 25- and 26-jewel versions are concurrent market variants, not a chronological progression. Seventeen-jewel movements appear in a 1958-era ref. 5508, a 5500 and a 1011 Eaton, and Rolex's 1978 service booklet still treats low-jewel 1520 and 1530 movements as current configurations.

The rim weights can be mistaken for a free-sprung system, but factory documentation confirms the regulator and inertia blocks. Two Bonhams descriptions call the 1520's balance "free-sprung Gyromax," an error that applies Patek Philippe's trademark to an index-regulated Rolex movement.

The 17-, 25- and 26-jewel counts are concurrent market variants. The 17-jewel version uses a different main plate and bridges, altered escape-wheel pivot geometry, and bushings in place of jewels in the automatic module. The going train and balance are unchanged, so jewel count does not affect timekeeping. Dated examples place 17- and 26-jewel movements together from the mid-1960s, with 25-jewel examples running alongside them.

Cal. 1535 is the non-chronometer date version of the 1530, introduced in 1957 for the Air-King-Date 5700/5701. Rolex's factory caliber table places it before the later 1520-based Cal. 1525, consistent with the production dates. Monochrome likewise assigns both calibers to the 5700, with 1535 first.

Cal. 3186 retains the Cal. 3135 architecture used by the 3185: 28.5mm diameter, 6.45mm height, 28,800 vph, and 31 jewels. It also keeps the plain-bearing oscillating-weight axle, part 568, shared with Cal. 3130, 3135, 3155, and 3175. Once lubricant migrates, the axle wears and requires replacement and riveting at service.

The jumping-hour click spring is the caliber's known failure point. A failed spring lets the local-hour hand glide instead of indexing in one-hour steps and can leave it loose on its wheel. Rolex superseded part 657 first with 657-1 and then 657-2; the later springs are stronger and slightly larger. The fault is documented across the 16710, 16570, 116710, 116713, 116718, and 116719, as well as Cal. 3187. It usually leaves other components undamaged. The hour-jump action should be checked on an unserviced watch.

Cal. 3187 inherited the 3186's jumping-hour click-spring failure. On affected watches, the local-hour hand glides instead of indexing in one-hour steps. Rolex revised the part twice, and serviced examples may carry the later, stronger spring.

Cal. 3000 was Rolex's last movement without a Breguet overcoil. It uses a flat hairspring, unlike the outgoing 1570 generation and the rest of the 3000 family. Microstella adjustment sets the rate without an index, the hairspring is glued to the balance stud, and shock protection is KIF. COSC certification used the standard &minus;4/+6 seconds-per-day tolerance.

The main wear point is the oscillating-weight axle, Rolex part 568, shared with Cal. 3135, 3155, 3175, and 3185. It runs in a plain sleeve bearing rather than a ball bearing. Once lubricant migrates, axle wear can produce rotor play and fine reddish dust. Replacing and riveting the axle is a routine service repair.

Both dial generations of the 214270 use Cal. 3132. The 2016 revision lengthened the hands and added luminous filling to the 3, 6, and 9 numerals, without changing the movement. Cal. 3132 also retains the 3130's plain-bearing oscillating-weight axle, which wears after its lubricant migrates.

Two wear points sit in the automatic works. The anodised purple-red reversing wheels, part 3135-540, are visible through the rotor cutout and identify the movement without disassembly. Failure produces free rotor spin without winding or gritty manual winding. Epilame belongs across the reverser assembly, while oil is confined to the arbor and bearing points; oil on the teeth or clicks can jam the mechanism. The oscillating-weight axle, part 3135-568, runs in a plain jewelled sleeve. Wear causes a rattle, rotor contact with the caseback, and red dust in the movement. Rolex supplied mainsprings in standard part 3135-311 and weaker 3135-311-1 versions, a relevant distinction when assessing a rebuilt movement.

The factory caliber table introduces Cal. 1580 in 1963, three years after the 1019's generally accepted launch around 1960. It lists the earlier anti-magnetic Cal. 1065M, 1066M, and 1080 from 1955, and a Milgauss 6541 is documented with Cal. 1080. Published evidence does not settle whether the earliest 1019s used Cal. 1580 or one of these 1030-family movements.

Cal. 5055 powers the yellow-gold ref. 19018, white-gold ref. 19019 and pyramid-bezel ref. 19028. Planned successors, Cals. 5235/5255 with a conventional stepper motor and 5335/5355 with a perpetual calendar, were cancelled before production.