RAF – 6B/159 wrist watch by LeCoultre

A longer time ago I actively collected military wristwatches. Now all of these beautifull watches by classic brands like IWC (Mark X), Longines (6B/159), Zenith (US Signal Corps) and Omega (airplane clock WW1) have been gone for years.

One of the RAF wristwatches by Jaeger LeCoultre had been on the wish list for quite some time but never materialized when I actively collected. By accident I came across a nice version recently so I picked it up. It was not in working order, research by the watchmaker turned out that the balance had to be replaced in the splendid 470 caliber. Expensive but possible so the repair is now on its way. In the meantime I only have a few photo’s to enjoy and share.

The Wrist Watch Mark 7a was a navigational watch used by the RAF and had the designation 6B/159 on the case. This model first existed in the “Weems” variation (around 1940) with a turnable bezel. Later (around 1942) the model came without the bezel but only the non hacking central seconds hand. This was relatively rare at that moment in time when subsidary seconds at the 6 position were still the standard. As this was a relatively complicated watch that needed to be of high qaulity due to its purpose. The watch was also needed in high quantities therfore it was sourced from many of the leading Swiss makers but most seem to be from 3 big name brands of that period Omega/Longines/ Jaeger LeCoultre.

The (Jaeger) Lecoultre 6B/159 had blued steel leaf hands as did the earlier Weems bezel model. It is thought about 5000 of these were produced in total (according to Knirim). Most seem to have been from one large batch produced in 1943 with the Broad Arrow marking above the 6B/159 designation (earlier models made in 1942 had the AM marking ipo the Broad Arrow). All the models with the cal. 470 were delivered in 1943/44 and not later, from 1945 onwards the 479 calabre was used.

All LeCoultre watches show the LeCoultre serial number next to the engraved markings of the RAF. Of this series the serial numbers on the case are mainly in the 158xxx up to 163xxx numbers which would correspong with the number of 5000 that is mentioned in the Knirim book. The military numbers do not correspond with the watch serial numbers I found out. They were not engraved in the same order as the case serial numbers but the range seems to be mainly in the A23xxx up to A26xxx numbers. All other brands used the same numbering starting with Axxx up to A 30xxx so it seems more than 30.000 examples of the 6B/159 were made for the RAF in 1943/44 and maybe even 1945.

All original dials are signed LeCoultre. The story is that there were many of these dials (for the US market naming) in stock so these were used exclusively for this military contract. There are several original dial variations but all with a white background. The case was a chromed brass alloy with a diameter of 32mm diameter and had a snap on case back.

The Ministery of Defense often replaced/repainted dials (probably as the case was not waterproof the dial often was damaged by condensation and dirt). They did not do this with original dials but re-painted the dials themselves using different fonts and many variations exist. The MoD replacement dial also exists in black and with the full Jaeger LCoultre name on it.

This dial is one of the MoD replaced dials and the font used seems very similar to the one seen on the Longines pictured here (photo from the Knirim book) but with the standard LeCoultre hands (which can be distinguished from other brands as seen in the Longines example below).

As the original case was not designed for military use, the chrome case materials (a kind of brass with chrome plating) suffered from corrosion. A stainless steel case of a larger size (36mm) was introduced in 1956. All models of the 6B/159 still in service were recased with the new case but these are relatively rare.