Calibre guide · Speedmaster
Omega Calibre 321: the Speedmaster's column-wheel chronograph
The Omega calibre 321 is a manual-wind chronograph movement with a column wheel, developed with Lemania as the 27 CHRO C12 in 1942 and made until 1968. It ran every Speedmaster from the 1957 CK 2915 to the 145.012, including the 105.012 worn on Apollo 11. The 2019 calibre 321 is a new-built copy for new watches.
What a vintage 321 sells for
Thousands to tens of thousands of US dollars
for a 321 Speedmaster. The 1957 CK 2915 is a six-figure watch at auction.
105.012 sold prices145.012 sold pricesEvery vintage Omega price
Real eBay sold prices, not asking prices. Affiliate links; opens in a new tab.
A 145.012 with a 321 sells for more than one with an 861, though both are correct. Within any reference, originality sets the price: the dial, hands and bezel it left the factory with, and a movement that has always been in that case.
Find a 321 on eBay
Live listings and real sold prices for the 321 references and the movement itself.
How to tell it's really a 321Affiliate links: Watch Breaker may earn a small commission. Opens in a new tab.
Quick facts
| Made | 1942 to 1968; the 27 CHRO C12 until Omega numbered it 321 in 1949 |
|---|---|
| Designed by | Lemania, as its calibre 2310 |
| Winding | Manual |
| Beat | 18,000 an hour (2.5 Hz, five ticks a second) |
| Size | 27.00 mm across, 6.74 mm high |
| Jewels | 17 |
| Power reserve | About 44 hours |
| Chronograph | Column wheel, lateral clutch, two pushers |
| Functions | Hours, minutes and small seconds; chronograph seconds, 30-minute and 12-hour recorders |
| Calibre number | On the balance cock |
| Revised | 1968; the parts that changed carry .1 on the end of the number |
Size, beat, pushers, marking and the 1968 revision: GF 620-4, 321 folios 1–7. Years: the Watch Breaker calibre register. Jewels and power reserve: published references.
How to tell it's a 321
- The column wheel. With the caseback off, look in the chronograph works for a small toothed turret under a cap, like a castle tower. The chronograph levers ride on its columns. The 861 has none; a flat cam does the same job.
- The beat. A 321 beats 18,000 times an hour, five ticks a second. An 861 or 1861 beats 21,600, six a second. A timegrapher, or a timing app held against the caseback, tells them apart without opening the watch.
- The number on the balance cock. GF 620-4 prints the 321's marking on the balance cock, the bridge that holds the balance wheel. The 27 CHRO C12 T1 PC AM, the same size, height and beat, is marked on the plate instead, and in the catalogue that is the only printed difference.
- The copper finish. Vintage 321s are copper-coloured. Early 861s have a similar pink finish, so the colour points to a 321 without proving it. The column wheel proves it.
Photos not clear enough to be sure? Send them in and I'll check the calibre against its factory sheet.
Which watches have a 321
Every Speedmaster up to the 145.012. These are the 321 references from the Speedmaster guide:
| Reference | What it is | From |
|---|---|---|
| CK 2915 | The first Speedmaster: steel bezel, broad-arrow hands | 1957 |
| CK 2998 | Black bezel; the second generation, and the first Speedmaster in space | 1959 |
| 105.002 · 105.003 | Straight lugs, no crown guards; the 105.003 is the watch NASA qualified and Ed White wore on the first American spacewalk | early 1960s |
| 105.012 | Crown guards and "Professional" on the dial; worn on Apollo 11 | mid-1960s |
| 145.012 | The changeover reference: a 321, then an 861 | 1967 |
The other 321 chronographs
The 321 wasn't only a Speedmaster movement. Omega's vintage database lists it in these references too, from the 1940s chronographs of its 27 CHRO C12 years to 1960s Seamaster and De Ville chronographs.
| Reference | Omega files it as | Year |
|---|---|---|
| CK 2451 · OT 2451 | Other | 1946 |
| OT 2468 | Other | 1946 |
| OJ 2439 · OT 2439 | Other | 1949 |
| OT 2884 | Seamaster | 1957 |
| KO 2907 | Seamaster | 1958 |
| CK 14364 | Seamaster | 1959 |
| CK 14904 | Seamaster | 1960–1962 |
| ST 105.0001 · ST 105.0005 | Seamaster | 1962 |
| ST 105.0004 | Seamaster | 1962–1965 |
| ST 145.0006 | Seamaster | 1966 |
| ST 145.0005 | De Ville | 1966 |
| BA 141.0010 | De Ville, 18k gold | 1966 |
Omega's vintage database, as held in the reference lookup. Omega files even the CK 2915 and the 105.012 under Seamaster, so the middle column is Omega's label, not the name on the dial.
321 vs 861 vs 1861 vs the 2019 321
| 321, vintage | 861 | 1861 | 321, 2019 | |
|---|---|---|---|---|
| Chronograph | Column wheel | Cam | Cam | Column wheel |
| Beat | 18,000 | 21,600 | 21,600 | 18,000 |
| Years | 1942–1968 | 1968 to the mid-1990s | Mid-1990s to 2021 | 2019 on |
| Servicing | Any skilled chronograph watchmaker; parts are scarce | Widely serviced; parts easier to find | Widely serviced | Omega only, in Bienne |
| Collector premium | The highest: 321 references sell for multiples of a 145.022 | The benchmark for a vintage Professional | Little; priced as a used modern watch | New-watch money; the steel model is listed around $15,500–17,500 on Chrono24 |
The 861 replaced the 321 because it was simpler to make: the cam does the column wheel's job with fewer, simpler parts. The 321 isn't more accurate or more reliable. Collectors pay for how it's made and where it went.
Chrono24 range as of September 2026.
Why is the 321 so expensive?
- It's the Moon movement. Wally Schirra's CK 2998 in 1962, the 105.003 NASA qualified in 1965, and the 105.012s on Apollo 11 all ran on a 321.
- There are fewer of them. It went out in 1968, while the 861 and 1861 that followed were made for more than half a century.
- The reissue raised the price of the name. Omega's 2019 remake sells as a five-figure new watch, and the vintage references sit above it.
- Servicing is harder. Swatch Group stopped supplying parts to independent wholesalers at the end of 2015, so vintage 321 parts come from old stock and donor movements. A new 321 goes back to Omega's workshop in Bienne.
The 2019 reissue
In 2019 Omega put the 321 back into production, rebuilt over two years from scans of the Speedmaster Gene Cernan wore on Apollo 17. It keeps the column wheel and the 18,000 beat. The first three watches were a platinum Speedmaster announced in December 2019, a steel model styled on Ed White's 105.003 in 2020, and one in Omega's Canopus gold in 2022. They are new watches with their own references, and none of them tells you anything about a vintage 321. For a vintage watch, go back to how to tell it's a 321 or what one sells for.
Servicing and parts
A vintage 321 can be serviced by any watchmaker who knows column-wheel chronographs. The hard part is parts. Sixty years on, the ones that give out are the parts that take the load: the mainspring, the hammers that snap the chronograph hands back to zero, the clutch that starts and stops the chronograph, and the small springs around the column wheel. Ask for the replaced parts back; on a 321 they're worth keeping.
Omega revised the 321 in 1968, and GF 620-4 prints the changes in the 321 section. The parts that changed carry .1 on the end of the number, so buy against the number your movement needs, not just the calibre. The same remarks in the section for the 320, the calibre the catalogue gives as the 321's base, list what you can check at the bench: the barrel arbor went from 3.70 mm to 3.00 mm across, the regulator angle from 25° to 45°, and the new pallet cock has no banking pins.
| Part no. | Part | In 1968 | Find it |
|---|---|---|---|
| 321.1204.1 | Barrel arbor | The revised arbor | eBay Every fit |
| 2520 | Screw | Replaced screw 2234 | Every fit |
| 2234 | Screw | The earlier screw | Every fit |
| 6180 | Bushing | New | Every fit |
Hunting a 321 part? Search 321 parts on eBay, or look a part number up in the parts finder. Can't find the number? Email id@watchbreaker.com with the part and I'll look it up in the GF 620-4 folios, free.
Part numbers and the 1968 remarks: GF 620-4, 321 folios 1–7 and 320 folios 1–8, as transcribed into the Watch Breaker parts database. Part numbers are Omega's; no catalogue pages are reproduced.
Questions people ask
What is the 321 movement?
The calibre 321 is Omega's manual-wind column-wheel chronograph movement, developed with Lemania as the 27 CHRO C12 in 1942 and made until 1968. It was in every Speedmaster from the 1957 CK 2915 to the 145.012. Omega put a new-built version back into production in 2019.
What is special about the Omega 321?
Its column wheel and its history. The column wheel is the older, harder-to-make way of controlling a chronograph, and the 321 was in the first Speedmaster in space, Wally Schirra's CK 2998 in 1962, and in the 105.012s on Apollo 11. It is not more accurate or more reliable than the 861 that replaced it. Collectors pay for how it is made and where it went.
Why is the Omega 321 so expensive?
It is the Moon movement, there are far fewer of them than the 861s and 1861s that followed, and parts are hard to find since Swatch Group stopped supplying independent wholesalers at the end of 2015. The 2019 reissue also put new-watch money on the name. Vintage 321 Speedmasters sell for thousands to tens of thousands of US dollars.
How do you get an Omega 321?
A vintage 321 means a Speedmaster made before 1968, or one of the other references on this page, bought used from eBay, a dealer or an auction. Check that the calibre is right for the reference before you pay. A new 321 comes from Omega as one of its reissue Speedmasters.
That's the question that sets the price. Six photographs and the weight, and I put it in writing: calibre confirmed against its factory sheet, case checked against Omega's own case data, serial dated, dial judged, three honest values. Within a day. US$75, and nothing to pay until I confirm the photos can answer it.
Watch Breaker is an independent identification specialist and parts dealer and is not affiliated with, endorsed by or connected to Omega SA or the Swatch Group. Omega is a trademark of Omega SA. Specifications and part numbers are transcribed from printed catalogues; reference pairings are from Omega's vintage database or community-graded where stated. Terms.