Not able to find all this information in one place, in this article I have mined information across the inter web to compile a summary and key points to note regarding the movements used in the Speedmaster Professional since it’s introduction in 1967. Think of this as the Penguin Book version for ‘beginner’ enthusiasts. I have interlaced my article with links to other wonderful sites with even more detail. Just be careful how far that habit hole goes.
321 (1946-1968)
861 (1968-1997)
1861 (1997-2020)
3861 (2020- )
Often, one of the more controversial aspects of which Speedmaster Professional to buy is that of it’s movement. Enthusiasts say the current version you can buy today with caliber 1861, at your local authorised or grey dealer is in fact not a Moon Watch and shouldn’t be sold as such, despite not significantly changing in look since 1967 and still flight certified by NASA (fact).
Return of the icon
Harsh, or is there some truth? Are Omega really cynically pulling the wool over our eyes and taking advantage of our nostalgic connection to this watch or are we just being a little too critical? Is this watch any less special or less authentic by not having the legendary 321 movement as worn by Neil Armstrong and Buzz Aldren on that historic day of 20th July 1969? Arguably the 1861 is ‘just’ an evolution, but does it still make a Moon Watch authentic?
This is after all a historic movement, one Omega made a fanfare for in 2019 with the re-release of the 321 movement in the Platinum and Ed White special editions.
Cal 321 in the 42mm 2019 Platinum & 2019 39.7mm Ed White Edition
Omega say: Known for its beautifully intricate design, the original Calibre 321 earned a notable place in history. It was used in a variety of models including the Speedmaster ST 105.003 (the model first tested and qualified by NASA and worn by astronaut Ed White during the first American spacewalk) and the Speedmaster ST 105.012 (the first watch worn on the moon).
Reintroducing a movement with such an important reputation as the 321 must be done with the utmost exactness. For the Calibre 321 project, OMEGA utilised a dedicated team of experts who worked efficiently over two years and in total secrecy to bring the movement to life. The small group was composed of researchers, developers and historians, as well as the finest craftsmen and experienced watchmakers. To protect the project’s exclusive details, the team even worked under the codename “Alaska 11”, in line with the names that OMEGA used for its secret Speedmaster designs for NASA in the 1960s and 70s.
Using the 2nd generation Calibre 321 as a reference, the OMEGA team compiled extensive historical research and original plans to reconstruct the movement as accurately as possible. Going even further, they also used “tomography” technology (digital scanning method) to see inside the true Speedmaster ST 105.003 timepiece that astronaut Eugene “Gene” Cernan wore on the moon during the Apollo 17 mission in 1972. Cernan was the last man to walk on the lunar surface and his Speedmaster is now housed at the OMEGA Museum in Bienne. Its Calibre 321 provided the perfect design criteria for OMEGA to follow.
As a result, even the most unique and iconic parts of the Calibre 321 have been reborn in respect to their authentic specifications. The movement wonderfully corresponds to the “moon period” of OMEGA’s history, with a construction that completely respects the designs from the past.
first omega in space
Reading up on the excellent Hodinkee.com site, the last Speedmaster reference to use the caliber 321 was the 145.012, which was produced for a relatively short period of time (1967 through 1968, with a few pieces from 1969 as production wound down). That reference was used extensively in manned space flight, and from the first time the caliber 321 went into space, with Wally Schirra (who wore his CK2998 aboard Mercury Atlas 8, in October of 1962) through to reference 145.012, the movement proved itself a sturdy, very reliable machine at the heart of one of the most renowned instrument wristwatches of all time.
CK 2998 First Omega in Space Edition with 1861 movement
Origin and Evolution of the 321 movement
Caliber 321 is known to be a robust, yet elegant chronograph movement. At 27mm in diameter and 6.74mm in height it is more compact than the other famous chronograph movement, the El Primero from Zenith at 30mm and 7.55mm. The 321 and subsequence 861 versions remain hand wound to the El Primero’s automatic winding.
Unlike today where the various watch making houses are pushing on with their in-house movements and collectors turn their noses up at anything less. Back when the 321 was developed, it was common place to collaborate on many of the parts, mostly movements. A descendant of the 27 CHRO C12, and a collaboration between Omega and Lemania, production of this movement spanned from 1946 to 1968 as both the Omega Cal 321 and the Lemania 2310 as used by the horological holy trinity, Patek Philippe, Audermars Piguet and Vacheron Constantin. Excellent company to be in.
Cal 1141 based on 2310
Vacheron Constantin – 47192
So, although the Cal 321 can trace it’s roots back to 1949 and was used in the earlier Speedmaster models, it was only fitted to the Speedmaster Professional range for a very short time, 2 or so years. This was enough time for NASA to procure sufficient quantities from Omega with the 321 movements to cover the subsequent Gemini and Apollo missions, right up to the re-issue of 56 Speedmaster Professional 145.022 watches after re-qualification for the Space Shuttle program with 861 movements.
So let’s ask ourselves if this really matters. The 321 was clearly at the end of it’s production run and was used as a bridging movement in the Speedmaster Professional for that very short period before the 861 was introduced before man had set a single foot on the moon. For collectors, this is pure heaven. A specific watch, connected to one of man’s greatest achievements available for only 2 years. No wonder these pieces now change hands for significant sums, with fewer coming on to market as buyers who know, don’t sell.
In 1968 with the introduction of caliber 861 Omega updated the base 321 with a few refinements including replacing the column wheel with a shuttle cam for added durability and lower cost, a flat balance spring and a tweaked beat rate to 21,600vph for improved precision.
The replacement of the column wheel and introduction of a cam to actuate the chronograph will always be a point of contention. Purists will gravitate to column wheel movements due to the crisper nature and accuracy. However, the change to the 861 movement saw no deterioration of function or accuracy in the 861. They are also more aesthetically pleasing, but given the Speedmaster is a tool watch, these points were secondary to the reliability and cost to the average owner. Open case backs were not thing, so how pretty the movement looked was not a consideration.
The other, more controversial change was Omega introducing the Delrin brake around 1973 to the 861 movement. The purpose of the brake is to hold the second recorder hand in position when the chrono function is paused. The metal brake was never inferior, but Omega changed to the plastic Delrin brake because it was cheaper to produce and put less wear on the second recorder wheel. The metal brake remains on clear case backed versions, and some would argue plastic parts have no place in a luxury watch. But Omega is not one to stop tinkering with a continuous improvement mindset. Star Wars is still Star Wars, even with the special edition CGI added later by George Lucas.
Photo above from Moon Watch Only shows the Delrin brake on the right hand image.
Before the phasing out of caliber 861, Omega released a limited 1992 Jubilee 27 CHRO C12 reference BA 148.0052 to celebrate the 321’s 50th anniversary. This was the first COSC certified hand wound movement for the Speedmaster, but sadly only in limited numbers as caliber 864. Check out this article from Revolution for the full details.
1992 Jubilee 27 CHRO C12 Reference BA 148.0052, First COSC Certified Manual-Wound Speedmaster (Image: ©Revolution)
Next giant leap for the speedmaster
In 1997, Omega say the natural evolution of the 861 used in many Moonwatch models, is the caliber 1861. Made with rhodium plating for greater stability and more jewels to further improvement precision, although still not COSC certified. Retaining the 861’s frequency and shuttle cam Omega mark the 1861 as the introduction of the Delrin brake, but there is plenty of evidence out there that shows this part in 861 movements from the early 70’s. The 1861 is fitted to all hand wound Speedmasters, including the CK2998 models.
In this current period we have also see highly decorated version of the 1861, such as the 1863 used in the ‘Sapphire Sandwich’ and the 1869 as used in the Apollo 8 special edition from 2018.
Cal 1869 from Apollo 8 and Caliber 1869 from the Professional
The 1861 movement has now been in service since 1997 in the Speedmaster Professional, and is the movement in the watch I purchased new in 2018.
In 2019, Omega used the 50th anniversary of the Apollo moon landing to launch their latest iteration of this movement, the 3861. Omega say it took 4 years to produce a caliber that could perfectly match the dimensions of the 1861 and achieve Master Chronometer certification. The 3861 improves on power reserve, performance and magnetic resistance and includes Omega’s revolutionary Co-Axial escapement and silicon Si14 balance spring.
Cal 3861 and the Apollo 11 50th Anniversary Speedmaster
Now this all sounds like a mouthful of Omega marketing BS, but read between the lines, and you can tell this is a ground up re-imagining of the movement that goes beyond just adding a few spoilers and a bigger turbo. No, this caliber changes everything. But as is the Omega way, what have they actually done? Well, not only do you now have a classically hand wound movement still, but you now have added ‘tool watch’ features. A longer power reserve, anti-magnetic and more accurate. As a Master Chronometer, Omega are giving you a watch that keeps 0 to +5s per day.
As we coast through the second decade of the 21st century, isn’t it fitting that Omega continues to follow it’s DNA with continuous improvement, and give us probably the best movement the Speedmaster Professional has ever had. What more fitting tribute than to have it’s debut in the 50th anniversary model.
I have it on good authority that caliber 3861 will be deployed into all the hand wound Speedmasters going forward, with the bread and butter Professional being replaced towards the end of 2020. The Speedmaster is in good hands.
I would like to thank both Quill & Pad, Fratello, Hodinkee and Revolution for their excellent articles of both the 321 movement and Speedmaster collecting. I have used some excerpts in this article to draw my own conclusions. I found some of the pictures used in this article through Google Images and Omega.com. If these pictures point out to be yours and you would like me to credit you, please let me know. I have credited the images on the YouTube channel based on the meta data within the image.
Hello Andy,
Very informative article,thank you.
Do you know if it’s possible to replace the clasp on my Speedmaster 3750.50.50 with the Seamaster clasp that has the “glidelock” type adjustments.Ive researched it and it appears to be expensive and fairly difficult.
Your opinion would be most appreciated,
Kind regards,
Lance Taylor.
Hi Lance – thanks for the comment and really pleased you enjoyed the article. I think your reference is 3570.50.50, which is a late 1990’s model. Looking at Moonwatch Only, this was a transitional model moving from tritium to luminova and 861 to 1861 movement. Another change was moving from the 16mm friction clasp to the 18mm 2 button clasp. Either way, you will have the pin and sleeve bracelet. I believe the micro adjust clasp needs screw and pin links, and am unsure if there is a link mod that can be done. It looks like some have done this on the old Bond Seamaster which has a similar 2 button clasp, but I don’t think it’s possible on the older style 16mm friction clasp. I have left a link for you where you may find further details:
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