Druckbare Version
I love these dials and number 770.....I would die for :verneig: - thanks for showing :gut:
GRANDE STEFANO -- THANKS FOR SHARING !!!! :verneig: :verneig:
Grazie mille! :gut:
Madonna, que bello orologio! And what an incredible Photographie skills.
Victor
Caro Stefano,
many thanks for your impressive description of the rare Ref. 5100.
Please allow me to add some technical information about the highly interesting movement of the 5100: The Beta21 caliber.
The quartz crystal of the Beta21 has a frequency of only 8192 Hz (2 exponent 13 instead of the todays use of 2 exponent 15 = 32768 Hz). Due to the high energy consumption of the old electronic circuits it was only possible to use 5 electronic divider steps to 256 Hz for realizing a lifetime of the battery of at least 12 months. Due to the missing of the remaining 8 divider steps the movement uses a so called swingmotor with a frequency of 256 Hz. The swingmotor drives through a toothed wheel with 256 teeth in conjunction with a ratched mechanism the second hand. This is the reason why the watch humes with a frequency of 256 Hz.
Due to the hume some people think the Beta21 is a tuningfork movement (like the Bulova Accutron system) but this is definitely not true. The Beta21 is a quartz movement, even if the watch humes and the second hand is running smoothly without seeing any steps.
Very strange is the quickset function of the date: The crown has to be pushed by the thumb and then in pushed position (!) be moved back and forward. The date changes then without influence of the hands. This is also the reason why the crown of the 5100 has a “fluted" surface and is not a screwed one like the Oyster-crowns.
The Beta21 was the first swiss quartz-movement for wristwatches released only shortly after the very first one from Seiko (Astron-caliber). As you had already mentioned the Beta21 was developed in the 60ies by a consortium (Centre Electronique Horloger, C.E.H.) consisting of several well known swiss watch manufacturers. So the Beta21 cannot only be found in the Rolex 5100, but also in an Omega (Electroquartz 8192 Hz), Patek Philippe, IWC, Jaeger etc. The Beta21 was a technical masterpiece, but a commercial desaster.
One further remark to the bracelets: Due to my knowledge there were two versions. The first batch of approx. hundred 5100 had a "less weight" bracelet (the elements were much thinner and formed like an “U”) and had a folded clasp (not concealed) with a rolex-crown at the side (!), from approx. serial No. 100 upwards the bracelet was like shown in your description.
Best Regards to Italy
Matthias
very interesting, thks for sharing stefano :dr: :dr Matthias
greets
Wum
Matthias, Stefano, thank you very much for sharing this :verneig:
In addition to my a.m. remark, please find following two pictures of a bracelet from the first batch (Ref. 5100 No. 57):Zitat:
Original von Prof. Rolex
.......
One further remark to the bracelets: Due to my knowledge there were two versions. The first batch of approx. hundred 5100 had a "less weight" bracelet (the elements were much thinner and formed like an “U”) and had a folded clasp (not concealed) with a rolex-crown at the side (!), from approx. serial No. 100 upwards the bracelet was like shown in your description.
......
http://img.photobucket.com/albums/v4...7-bracelet.jpg
http://img.photobucket.com/albums/v4...nr57-clasp.jpg
(Source: unfortunately unknown)
Best Regards
Matthias
Wow, very interesting... :gut: :gut:
Never saw these beauties before..
Thanks for posting
Thank you :gut: :gut:
Cheers, Stefano & Prof. Rolex