Panerai's first watch case was the Radiomir one, characterised by its strap attachments formed from steel wires bent and welded to the case. In about 1940, the Panerai workshops in Florence perfected a new case, designed to meet the increasing demands of the commandos of the Italian Navy.
The lugs became larger and much more solid, being milled from the same block of steel as the case, of which it was an integral part. The cushion-shaped outlines were now less accentuated. The winding crown was slightly larger and cylindrical rather than troncoidal. The overall thickness of the watch increased from about 15 mm to almost 17 mm.
The case had evolved from the one presented in 1936 which is known today as the Radiomir – a term which originally referred to the luminous material patented by Panerai to make the dial readable in the dark – but it presented some innovations designed to make its construction even more solid and hard wearing. This case was one more step in the direction of the Luminor case, which came out a few years later.
So was born the Radiomir 1940 case, which Officine Panerai revisited last year – with the same forms of the original but in a thinner version - introducing the new Radiomir 1940 with a 47 mm case size. This year, during the Salon de l'Haute Horlogerie 2013 in Geneva, four new models have been added to the Radiomir 1940 product line: the Radiomir 1940 42 mm in steel (ref. PAM00512) and in pink gold (ref. PAM00513) and the Radiomir 1940 3 Days 47 mm in steel (ref. PAM00514) and in pink gold (ref. PAM00515).
The 42 mm versions adopt the P.999 hand-wound movement, the smallest and thinnest in the wide range of calibres produced by the Officine Panerai manufacture in Neuchâtel. Visible through the window in the sapphire crystal window which opens on the back, the P.999 has a power reserve of 60 hours and a balance which oscillates at 21,600 alternations/hour (equivalent to 3 Hz). In the red gold version, where the arrises of the bridges are chamfered, smoothed and polished, the active length of the balance spring is adjusted by a swan-neck regulator, while in the steel version it is adjusted by curb pins.
The 3 Days 47 mm - easily recognisable not only for the larger size but also for the date display at 3 o'clock - is fitted with the P.3000 calibre, developed and produced entirely in the Officine Panerai manufacture in Neuchâtel. Hand-wound and with a diameter of 16½ lignes, the P.3000 calibre has a power reserve of three days achieved by means of two spring barrels in series. The P.3000 calibre also has the device which enables the hour hand to be adjusted in jumps of one hour foreward or backward, so that its adjustment does not interfere with the progress of the minute hand or the running of the watch.
The steel cases are made of AISI 316L stainless steel, a grade extremely resistant to corrosion, or of 5Npt red gold, an alloy with a high percentage of copper, which gives the colour greater intensity, and a proportion of platinum, which helps to exclude oxidation.
Below, comparisons of the 42 mm and 47 mm models and related movements.