Model guide · Vintage models
Vintage Omega Ladymatic
The Ladymatic was Omega's ladies' automatic. Omega's own vintage database lists 19 references from 1954 to 1975, running on five calibres: the little 455 in the 1950s, then the 661, 670, 671 and 681 from 1963. Find your reference below and you have your movement, your metal and the parts that fit it.
Years are the years Omega's database gives for the references. Parts counts are from Omega's GF 620 catalogues; tap a calibre for its parts.
Find your reference
The reference is stamped inside the caseback. Read the letters in front of it too: they tell you the metal.
The 1950s Ladymatic: calibre 455
| Reference | Year | Case | Calibre |
|---|---|---|---|
| OT 16167 · OT 17082 | 1954 | 18k solid gold | 455 |
| CK 2940 | 1957 | Stainless steel, 19.5 mm | 455 |
| OT 2942 | 1957 | 18k solid gold | 455 |
| KO 10999 | 1959 | Gold cap on stainless steel | 455 |
| S 5270 | 1961 | Gold-filled, US collection | 455 |
| OT 17143 | 1961–1962 | 18k solid gold, 18.3 mm | 455 |
Find a 455 Ladymatic on eBay: For sale now What they sold for
The 1960s and 1970s Ladymatic: calibres 661, 670, 671 and 681
| Reference | Year | Case | Calibre |
|---|---|---|---|
| BA 555.0001 | 1963 | 18k solid yellow gold | 661 |
| BA 551.0006 | 1963–1969 | 18k solid yellow gold, 18 mm | 661 |
| BA 551.0008 | 1963–1967 | 18k solid yellow gold, 18 mm. Omega files it under De Ville | 661 |
| ST 551.0002 | 1965 | Stainless steel | 661 |
| JD 565.0001 | 1965 | Gold-plated | 670 |
| BA 561.0005 · BA 565.0003 | 1965 | 18k solid yellow gold | 671 |
| KD 561.0005 | 1965 | Gold-plated | 671 |
| ST 566.0001 | 1965 | Stainless steel | 681 |
| JD 566.0011 | 1965 | Gold-plated | 681 |
| MD 566.0002 | 1966 | Gold-plated | 681 |
| BA 751.0253 | 1975 | 18k solid yellow gold. Omega files it under De Ville | 661 |
Find a 1960s Ladymatic on eBay: 661 for sale 661 sold 681 for sale 681 sold
Source: Omega's vintage database, as held in the reference lookup. A reference not listed here may still be right. Send it and I'll check it. This page covers the vintage Ladymatics in those records. Omega has used the name again on modern watches, which aren't covered here.
The five calibres, from the factory catalogue
Omega's catalogues print each calibre with a short designation. RA is automatic, SC is centre seconds, PC is shock protection, CAL is the date and AM is antimagnetic.
| Calibre | Omega's designation | Jewels | Beat (A/h) | Height | Source |
|---|---|---|---|---|---|
| 455 | 16 RA SC PC AM 17p | 17 | 19,800 | 5.50 mm | GF 620-3 |
| 661 | 15 RA PC AM 24 pierres, from the 660 | 24 | 19,800 | 4.25 mm | GF 620-5, folio 1 (1963) |
| 670 | 17.50 RA SC PC AM 17 jewels | 17 | 19,800 | 4.30 mm | GF 620-5, folio 1 (1963) |
| 671 | Derived from the 670 | not printed | 19,800 | 4.25 mm | GF 620-5 |
| 681 | 17.50 RA SC PC CAL AM 24 pierres | 24 | 19,800 | 5.00 mm | GF 620-5, folios 1–2 (1963) |
The 661's designation carries no SC, the code for centre seconds. Measure yours against these in the calibre lookup.
Inside the 455: a 450 in a smaller coat
The 455 is 16 mm across. Omega's Technical Guide No. 5, October 1955, made it the smallest round calibre of its style, built for small ladies' watches, with about 40 hours on a full wind. Omega's GF 620-3 prints it as a calibre of its own, but look at the part numbers and most of them belong to the 450.
The 13 that carry a 455 number are the train wheel bridge 455.1003, the upper automatic bridge 455.1031, the mainspring 455.1208 and the motion work. Everything else comes from the 450 or the shared numbers. So hunt 455 parts by the part number, not the calibre. A 450.1428 is the same part whatever the listing calls the movement. The parts finder lists every one.
Taking the automatic off, as Omega printed it
- The rotor. There is no screw to undo. Turn the eccentric in the key-bolt a quarter turn, then turn the movement upside down: the rotor 450.1026 and the key-bolt drop out by themselves.
- The automatic block. Remove the two screws 2259 that hold it to the barrel bridge. The block comes off in one piece, with every part of the automatic device.
- Split the block. Remove the two screws 2258 joining the lower bridge 450.1033 to the upper bridge 455.1031.
- The parts inside, in the order printed: the pawl-bearing yoke 450.1419, the winding wheel with axle 450.1428, the winding wheel with pinion 450.1434 and the driving gear for the ratchet wheel 450.1437.
- The rest of the movement. The guide says nothing special: take it apart as a usual movement.
Source: Omega Technical Guide No. 5, The 455 Caliber (October 1955), pages 2 and 3. The rotor number is from GF 620-3; the guide doesn't print it.
455 movements and parts on eBay: For sale now What they sold for
Which screw goes where in the 455
A screw number tells you the thread and the head, not the job. The job is printed in each calibre's own section, and in the 455 it is different from other calibres. These are the ones Omega gives a job for in the 455.
| Screw | Its job in the 455 | How many | Printed in |
|---|---|---|---|
| 2257 | Barrel bridge, train wheel bridge and balance cock | 4 | GF 620-3, folio 3 |
| 2106 | Pallet cock | 1 | GF 620-3, folio 3 |
| 2102 | Crown wheel core thread direction not printed | 1 | GF 620-3, folio 4 |
| 2138 | Friction spring of the sweep second pinion | 1 | GF 620-3, folio 4 |
| 2516 | Dial | 2 | GF 620-3, folio 4 |
| 2621 | Case dog-screws | 2 | GF 620-3, folio 4 |
| 2259 | Automatic block to barrel bridge | 2 | Technical Guide No. 5 |
| 2258 | Joins the two automatic bridges | 2 | Technical Guide No. 5 |
| 2262 | Rotor axle 450.1400 to the lower bridge | 1 | Technical Guide No. 5 |
| 2265 | Bearing 450.1438 for the driving gear | 1 | Technical Guide No. 5 |
The same 2257 holds three different bridges, so if you lose one, that is the number to buy. GF 620-3 lists 21 screws for the 455 in all: see every one. A bench-order film of the 455, with every part number on screen, is in the works on YouTube.
Is it gold?
Ten of the 19 references are 18k solid gold: every OT and BA in the tables above. An 18k case is stamped 750. KO is gold cap on steel, S is gold-filled, JD, KD and MD are gold-plated, and CK and ST are steel. On a gold-plated case, brass showing at the lug edges means the gold has worn through. Gold or plated? covers every mark.
On a solid gold Ladymatic the gold sets the floor price, even if the movement doesn't run. Weigh your Omega turns a kitchen-scale weight into a gold value.
18k Ladymatics on eBay: For sale now What they sold for
Is your Ladymatic all original?
The reference, the calibre and the dial have to agree. Six photos and the weight, and I check them against Omega's own records and put it in writing. Nothing to pay until I confirm the photos can answer it.
What it's worth
Three numbers matter: what the same reference with the right calibre actually sold for, what the parts would bring, and, on an OT or BA case, the gold. Use the “What they sold for” links on this page rather than asking prices. What's my Omega worth? explains all three.
Dating one
The serial is on the movement; the serial number lookup gives the year band. It should land in or after the year the reference appears above.
Before you buy one
- The reference and its letters, from inside the caseback. The letters tell you the metal.
- The movement, with the calibre number readable. It has to match the reference.
- The dial, square on and in daylight. Even print, nothing smudged or thick.
- The lugs from the side. No brass showing on a gold-plated or gold-capped case.
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.
Questions people ask
What movement is in my Omega Ladymatic?
It depends on the reference. Omega's database lists the 455 in the Ladymatics of 1954 to 1962, and the 661, 670, 671 and 681 from 1963. The 681 is the one with a date. The calibre number is on the movement, and the reference inside the caseback tells you which one should be there.
Is my Omega Ladymatic gold?
Read the letters in front of the reference. Omega lists the OT and BA references as 18k solid gold, stamped 750. KO is gold cap on steel, S is gold-filled, JD, KD and MD are gold-plated, and CK and ST are steel.
How do I get the rotor off an Omega 455?
It doesn't unscrew. Omega's Technical Guide No. 5 (October 1955) says to turn the eccentric in the key-bolt a quarter turn and turn the movement upside down; the rotor and key-bolt drop out by themselves.
Why are most Omega 455 parts numbered 450?
Because the 455 is built mostly from 450 parts. Of the 101 part numbers Omega's GF 620-3 lists for the 455, only 13 carry a 455 number. Search by the part number, not the calibre.
Is there a service manual for the Omega 455?
Omega's Technical Guide No. 5 (October 1955) covers the 455, including how the automatic comes apart, and the GF 620-3 catalogue lists its parts. Both are in the Watch Breaker database, and a bench-order film of the 455 is in the works.
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. Reference data is from Omega's vintage database; calibre and parts data are transcribed from Omega's GF 620-3 and GF 620-5 catalogues and Technical Guide No. 5; no pages are reproduced. eBay links are affiliate links. Terms.