RAF, Encircled T Dial
Mark XI 6B/346 — RAF, Encircled T Dial
Triangle dial with an encircled T above 6 showing tritium lume, introduced when the MoD replaced radium; earlier watches received these dials at service, so many early cases carry one. Only RAF dials have the T.
At least 7,400 IWC watches for the RAF; IWC records identify more than 8,000 military movement numbers, with about 600 more thought to await confirmation (Horological Journal 2004).
Identifying details
- Circle-T
Encircled “T” at six o’clock marking tritium lume.
- Military caseback engraving
Issue markings on the caseback, e.g. stock number, broad arrow, issue number and year.
- Military issue
Issued to armed forces.
- Broad arrow on dial
British government-property broad arrow printed on the dial (also struck on case and movement).
- Triangle at 12
Luminous triangle in place of the numeral 12.
- Soft-iron inner case
Soft-iron inner case and dial forming a cage that shields the movement from magnetic fields.
Variants of 6B/346
Reference overview →| Variant | Production |
|---|---|
| RAF, White 12 Dial | 1949–1952 |
| RAF, Triangle Dial Without T | 1952–1963 |
| RAF, Encircled T DialCurrent | 1963–? |
| RAF, Encircled T Dial · Encircled T, Hooked 7 | Undated |
Case & movement
- Reference
- 6B/346
- Production
- 1963–?
- Case serials
- Case material
- Stainless steel
- Case diameter
- 36 mm
- Crystal
- Acrylic, held by a screwed retaining ring
- Movement
- Manual winding
- Date
- No
More specifications (1)
Movement
IWC 89
Albert Pellaton’s hand-wound centre-seconds calibre with indirect seconds drive and a Breguet hairspring. The Mark XI version stops the seconds for synchronisation. Early batches had no shock protection; later ones were fitted with Incabloc.
Manual winding · Introduced 1946 · 18,000 vph · 17 jewels
Read more
- Time Spec: The Mark XIRead more at Worn & Wound (opens in a new tab)
- ‘Man is Not Lost’ – an Account of the Mk 11 Navigational WristwatchRead more at Horological Journal (British Horological Institute) (opens in a new tab)
- RAF IWC Mark XI 6B/346Read more at Hairspring (opens in a new tab)
- Wednesday Afternoon Find: A Vintage IWC Mark XI For SaleRead more at HODINKEE (opens in a new tab)