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Author Topic: My first Accutron  (Read 2608 times)
Angel
Zeppelin Captain
*****
United Kingdom United Kingdom


Chrome dome, goggles on, dressed all in rubber...


« on: May 21, 2009, 08:12:19 pm »

Received in the mail today  Grin

Purchased from Ebay (pictures taken from the auction).

I'm well chuffed, it's really pretty and in great nick. 1976, 218 movement, new strap.


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"With a rifle, you can kill one man; but with a machine gun, you can make a whole army keep its head down." - Jeremy Clarkson

Buns are obviously not designed for their aerodynamic properties.
HAC
Steam Theologian
Zeppelin Overlord
*******
Canada Canada


HAC_N800
« Reply #1 on: May 21, 2009, 08:28:54 pm »

Welcome to the "hummer club" I've been collecting and playing with accutrons for a good 10 years now. Fascinating watches.
Looks like you god a nice one there. I always found the glass smooth sweep of an Accutron second hand to be quite something, as well as the amazing technology inside it.
I have a spare  original series 218 booklet/manual that came with the watches, if you'd like it, PM me a mailing address (freebie, no charge)

Cheers
Harold
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You never know what lonesome is , 'til you get to herdin' cows.
Angel
Zeppelin Captain
*****
United Kingdom United Kingdom


Chrome dome, goggles on, dressed all in rubber...


« Reply #2 on: May 21, 2009, 08:40:17 pm »

HAC, I love you.  Smiley
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rogue_designer
Zeppelin Admiral
******
United States United States


clockwork gypsy


« Reply #3 on: May 21, 2009, 08:49:29 pm »

Nice! That appears to be in great condition (and very generous of Harold on the manual). Smiley

I love my 218. I need to send it in to have the winding stem reset properly and a new crystal placed. But I can just stare at that sweep all day long...

actually - I'm probably more productive when I don't wear it... hmm.
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Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam.
(Si hoc legere scis nimium eruditionis habes. But deserve a nice glass of absinthe. I have some Montemarte in the cabinet, if you wish.)
HAC
Steam Theologian
Zeppelin Overlord
*******
Canada Canada


HAC_N800
« Reply #4 on: May 21, 2009, 10:58:05 pm »

Nice! That appears to be in great condition (and very generous of Harold on the manual). Smiley

I love my 218. I need to send it in to have the winding stem reset properly and a new crystal placed. But I can just stare at that sweep all day long...

actually - I'm probably more productive when I don't wear it... hmm.
I can email you the repair manual, if you wish, as a matter of interest... Let me know.. (Its a nice to know sort of thing, but without the specialized tools you need for hummers, well...  Grin )
Cheers
Harold
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Angel
Zeppelin Captain
*****
United Kingdom United Kingdom


Chrome dome, goggles on, dressed all in rubber...


« Reply #5 on: May 22, 2009, 05:52:13 pm »

Interesting paradox my dad just pointed out to me when I mentioned how the second hand constantly sweeps:

The Accutron is a digital watch with an analogue display(doesn't stop at set points, and most analogue clocks(mechanical) are digital in display(tick, tock).

Crazy shit, eh?
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rogue_designer
Zeppelin Admiral
******
United States United States


clockwork gypsy


« Reply #6 on: May 22, 2009, 07:47:56 pm »

Well, not really digital, as there are no bits and bytes involved (electro-mechanical is more accurate). But I see what he was getting at. Yeah.

Pretty fun.

It actually does stop at set points, it's just that they are so minute, its very hard for us to perceive them as anything other than a smooth, constant sweep.
« Last Edit: May 22, 2009, 07:49:29 pm by rogue_designer » Logged
HAC
Steam Theologian
Zeppelin Overlord
*******
Canada Canada


HAC_N800
« Reply #7 on: May 22, 2009, 08:18:08 pm »

Accutron basics - from  a work by Rob Berkavicius:

" Like conventional watches, Bulova Accutrons have a train of gear wheels to drive the hands. And that is basically where the similarity ends. In an Accutron, there are two areas of special interest to us boffins. One is the Electronic Circuitry and the other is the Index Mechanism .

The Electronics
 While it is relatively simple, it is neverthless interesting how the electronics driving the Accutron works. The electronic circuit combined with the tuning fork forms a simple oscillator. Each of the ends of the tuning fork has a little magnet on it. The fork provides the resonant or tuned part of the circuit. Both of these magnets are surrounded by a coil of very fine wire attached to the body of the watch.
  Power from the battery flows through the transistor, and then through both of the driving coils. One of the coils (the one which is attached to the plate holding the transistor and its components) also has a secondary coil built into it. When the fork springs one way, this secondary coil provides a feedback voltage which cause the transistor to almost stop the flow of current in the driving coils, and stop driving the fork. When the fork springs back the other way, this feedback coil generates a "reverse" voltage, which causes the transistor to allow current to flow in the driving coils again. The fluctuating current in the driving coils produces a varying magnetic field, which alternately attracts and repels the tuning fork magnets. Thus it keeps on vibrating. The system is self-regulating. If the watch receives a jolt which adds to the fork vibration, the circuit automatically reduces power to the fork until it reaches the normal amplitude of vibration. The reverse is also true.
  One of the more interesting features of the electronics are the coils themselves. Each Accutron coil has 8,100 turns of insulated copper wire of 0.015mm diameter (or about 1/2000th of an inch). That equates to about 80 meters (or nearly 90 yards) per coil. The wire is about one-third the thickness of a human hair. Truly Amazing!

The Index Mechanism
  This mechanism provides the means for converting the vibrations of the tuning fork into rotary motion. Even today, it is considered a truly remarkable engineering accomplishment. Though the dimensions of the working parts are incredibly small, the operation of the index mechanism is elegantly simple, and its robustness and reliability legendary. Neverthless, it is very delicate and requires special handling techniques during servicing and adjustment. The index wheel can be destroyed by simply touching it on its rim. It must be handled by its pinion only.
  It consist of two very fine flat springs (or "fingers"), each with a small ruby jewel cemented with epoxy onto one end. One of the springs (the pawl finger) is attached to the body of the watch by a small movable carrier and post. The other (the index finger) is attached to a post mounted on one arm of the tuning fork. The jewels of each finger rest on a special ratchet wheel (the index wheel) which has very small triangular shaped teeth. These teeth are so small, they cannot be seen without the aid of a microscope.The positions of the index and pawl jewels relative to each other is adjusted by moving the pawl jewel carrier. Correct adjustment is necessary to allow for variations in fork amplitude during the life of the battery. This is known as "phasing" the index mechanism, and requires good watchmaking skills, experience on Accutrons, and a good understanding of the operation of the index mechanism to be carried out correctly.
  In operation, when the fork moves towards the index wheel, the index jewel pushes the wheel around slightly more than one tooth. The wheel is then locked in place by the pawl jewel, so when the fork and index jewel moves back away, the index wheel stays stationary. This occurs once for every vibration of the fork, or 360 times a second for a 214 or 218 Accutron movement.
  The index wheel of a 218 movement is 2.40mm (0.095") in diameter and has 320 teeth, each of which is about 0.01mm high (0.0004") and 0.02mm (0.0008") wide. The index and pawl jewels are perfect little square blocks of synthetic ruby, 0.18mm (0.007") square and 0.06mm (0.002) thick. How these parts were manufactured has remained a closely-guarded secret."

Cheers
Harold
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