Here we have the legendary L139. The “L” stands for ‘luxus' or luxury. This has been my grail pen since the day I read about it. I love the “tie” clip, it is ever so elegant. Also, notice the cap and cap crown have no imprints as is expected from this model. The three cap bands - two thin silver rings and one fat gold band with MB imprints in the centre are exclusive to the vintage 129, 139 and 149 models. The nib on this pen was also advertised as having a "fine chiselling/imprinting" that we do not see on the plain nibs of the 138 and down the line (as apparent from a catalogue of the 1930s).
The nib on my pen is made of palladium, as confirmed by the inscription of the fancy "P" on it. I suspect this nib was used for a very short time - precisely around 1939. WWII started at just that time and restrictions were placed on the use of gold. Montblanc moved to steel nibs soon in the early 1940s and most 13x pens are found with a steel alloy. Maybe palladium was used just during the transitional phase from gold to steel?
The cap top crown and blind cap are made of ebonite while the rest of the pen is celluloid. The 139 was positioned as "extra massive" or seriously large. It was the biggest pen in the 13x series and it is large by any standard.
Pelikan had already invented the piston filler in the early 1920s, but Montblanc resisted using this technology because its designers were afraid that ink would leak past the cork and the pen would "sweat" in situations where it experienced pressure changes. MB finally caved and started producing piston fillers in the 1930s. Of course, they had to out-tech the competition, and so they made the telescopic piston for their Meistersück series to reflect their technological superiority!
One of the unique selling points of the 13x series was its telescopic piston which claimed to allow double the ink capacity of ordinary pistons. Here we can see the original patent filed on 1st August 1939 by Rosler et al. Normal pistons have a single-stage extension and retraction. However, the telescopic piston had a two-stage mechanism such that the second stage would collapse within the other first This ingenious system meant that the piston itself took up almost half the space of a typical piston inside the barrel, thereby leaving all that extra space for more ink. Unfortunately, it was not the most cost-efficient to produce and was also difficult to maintain, and so modern iterations of the 14x do not use it.
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