Discussion
Does anyone still make wind-up watches?
Also does anyone have an opinion on something like this?
http://cgi.ebay.co.uk/VINTAGE-SWISS-OMEGA-SEAMASTE...
Also does anyone have an opinion on something like this?
http://cgi.ebay.co.uk/VINTAGE-SWISS-OMEGA-SEAMASTE...
I'm really looking for something a bit cheaper and with a similar simple look as the vintage omega but I wasn’t sure if anything like that is available new? I also just like the idea of something with a mechanical movement rather than quartz.
I have a datejust that I have worn every day for the last 7 years but I seem to be going on lots of stag-dos to Eastern Europe and I rather not have it ripped of my arm by some heavies in a club or anywhere else!
I have a datejust that I have worn every day for the last 7 years but I seem to be going on lots of stag-dos to Eastern Europe and I rather not have it ripped of my arm by some heavies in a club or anywhere else!
Edited by cjm on Wednesday 23 May 00:36
Poljot still make very good wind up watches. Very, very well put together and loads of styles to choose from. Ranging from "speedmaster like" Strumanskie chrono's to simple slim classic watches like the one in your link.
Make sure you aim for a proper "crylic" version (ie. no english written on the watch) because in my personal experience there seems to be a drop in quality on the western versions.
Make sure you aim for a proper "crylic" version (ie. no english written on the watch) because in my personal experience there seems to be a drop in quality on the western versions.
lowdrag said:
anonymous said:
[redacted]
Amazing what you learn on this site. I had never even thought of that. Interestingly, why didn't they just take quartz watches then? You've got me curious. Was it just down to a sponsoring reason?They didn't get sponsoring - infact in the initial tests NASA bought all of the contenders at normal prices from a normal jewellers without mention of the project (which was obviously secret anyway). The second test allowed manufacturers to submit watches and some of the US chaps specially developed or improved their watches to pass the tests. The Speedy still won.
tertius said:
anonymous said:
[redacted]
I don't think that's right at all. Automatics need momentum not gravity.See for example here and here.
If you stood and kept rotating your wrist you would get the same effect in zero-G, but how convenient is that?
anonymous said:
[redacted]
Well centrifugal force doesn't exist so assuming that's what you were referring its certainly not that.The point is that an automatic WILL work in zero G (and according to at least one of those links has been shown to) all it requires is irregular movement of the watch, which will make the rotor move, not gravity.
There may be good reasons for preferring a manual over an auto, but not working due to the absence of gravity isn't one of them.
cjm said:
Does anyone still make wind-up watches?
Also does anyone have an opinion on something like this?
http://cgi.ebay.co.uk/VINTAGE-SWISS-OMEGA-SEAMASTE...
i think that is a lovely looking watch Also does anyone have an opinion on something like this?
http://cgi.ebay.co.uk/VINTAGE-SWISS-OMEGA-SEAMASTE...
and am very tempted to get one 
. there seem to be quite a few on ebay - can anyone give me an idea of what would be a reasonable price to get one for.thank you
from wikipedia
Centrifugal force (from Latin centrum "center" and fugere "to flee" ) is a term which may refer to two different forces which are related to rotation. Both of them are oriented away from the axis of rotation, but the object on which they are exerted differs.
A real or "reactive" centrifugal force occurs in reaction to a centripetal acceleration acting on a mass. This centrifugal force is equal in magnitude to the centripetal force, directed away from the center of rotation, and is exerted by the rotating object upon the object which imposes the centripetal acceleration. Although this sense was used by Isaac Newton,[1] it is only occasionally used in modern discussions.[2][3][4][5]
A pseudo or "fictitious" centrifugal force appears when a rotating reference frame is used for analysis. The (true) frame acceleration is substituted by a (fictitious) centrifugal force that is exerted on all objects, and directed away from the axis of rotation.
Both of the above can be easily observed in action for a passenger riding in a car. If a car swerves around a corner, a passenger's body seems to move towards the outer edge of the car and then pushes against the door.
In the reference frame that is rotating together with the car (a model which those inside the car will often find natural), it looks as if a force is pushing the passenger away from the center of the bend. This is a fictitious force--not an actual force exerted by any other object. The illusion occurs when the reference frame is the car, because that ignores the car's acceleration. A number of physicists treat it much as if it were a real force, as they find that it makes calculations simpler and gives correct results.
However, the force with which the passenger pushes against the door is real. That force is called a reaction force because it results from passive interaction with the car which actively pushes against the body. As it is directed outward, it is a centrifugal force. Note that this real centrifugal force does not appear until the person touches the body of the car (ignoring any force exerted by the seat on the person's behind, etc). The car also exerts an equal but opposite force on the person, called "centripetal force". In this case the centrifugal force is canceled by the centripetal force, and the net force is zero, thus the person does not accelerate with respect to the car.
Centrifugal force (from Latin centrum "center" and fugere "to flee" ) is a term which may refer to two different forces which are related to rotation. Both of them are oriented away from the axis of rotation, but the object on which they are exerted differs.
A real or "reactive" centrifugal force occurs in reaction to a centripetal acceleration acting on a mass. This centrifugal force is equal in magnitude to the centripetal force, directed away from the center of rotation, and is exerted by the rotating object upon the object which imposes the centripetal acceleration. Although this sense was used by Isaac Newton,[1] it is only occasionally used in modern discussions.[2][3][4][5]
A pseudo or "fictitious" centrifugal force appears when a rotating reference frame is used for analysis. The (true) frame acceleration is substituted by a (fictitious) centrifugal force that is exerted on all objects, and directed away from the axis of rotation.
Both of the above can be easily observed in action for a passenger riding in a car. If a car swerves around a corner, a passenger's body seems to move towards the outer edge of the car and then pushes against the door.
In the reference frame that is rotating together with the car (a model which those inside the car will often find natural), it looks as if a force is pushing the passenger away from the center of the bend. This is a fictitious force--not an actual force exerted by any other object. The illusion occurs when the reference frame is the car, because that ignores the car's acceleration. A number of physicists treat it much as if it were a real force, as they find that it makes calculations simpler and gives correct results.
However, the force with which the passenger pushes against the door is real. That force is called a reaction force because it results from passive interaction with the car which actively pushes against the body. As it is directed outward, it is a centrifugal force. Note that this real centrifugal force does not appear until the person touches the body of the car (ignoring any force exerted by the seat on the person's behind, etc). The car also exerts an equal but opposite force on the person, called "centripetal force". In this case the centrifugal force is canceled by the centripetal force, and the net force is zero, thus the person does not accelerate with respect to the car.
Edited by SpydieNut on Wednesday 23 May 16:16
The centripetal force is the external force required to make a body follow a circular path at constant speed. The force is directed inward, toward the center of the circle. Hence it is a force requirement, not a particular kind of force. Any force (gravitational, electromagnetic, etc.) can act as a centripetal force. The term centripetal force comes from the Latin words centrum ("center" ) and petere ("tend towards" ).
The centripetal force always acts perpendicular to the direction of motion of the body. In the case of an object that moves along a circular arc with a changing speed, the net force on the body may be decomposed into a perpendicular component that changes the direction of motion (the centripetal force), and a parallel, or tangential component, that changes the speed.
The centripetal force always acts perpendicular to the direction of motion of the body. In the case of an object that moves along a circular arc with a changing speed, the net force on the body may be decomposed into a perpendicular component that changes the direction of motion (the centripetal force), and a parallel, or tangential component, that changes the speed.
Edited by SpydieNut on Wednesday 23 May 16:18
anonymous said:
[redacted]
Umm, did you read any of the articles I linked to? 
From the Wikipedia article: "Reportedly NASA assumed that the automatic winding mechanism was based on pendulum action like Harwood's original design, requiring either a gravity field or constant acceleration. The weightless environment therefore raised doubts about the ability of an automatic watch to wind itself. In fact a full 360-degree winding mechanism should work even better in low or zero gravity, where the friction experienced by the mechanism is lower. The rotor can thus move longer and transfer more energy into the spring. The rotor is in any case easily activated by momentum and not dependent on gravity."
Also the Fortis B-42 Automatic Chronograph is flight qualified by the Russian space agency so I think we can be confident an automatic watch does work in space.
Re. centrifugal force - its a bug bear of mine when people refer to it meaning an outward force on a rotating object. I thought that's what you were doing. Sorry.
As for the centrifuge it works like this: it works by swinging its contents around in a circle and using their inertias to make them separate. The various items in the centrifuge have different densities and other characteristics that affect their paths as they revolve around the center of the centrifuge. Inertia tends to make each item go straight while the centrifuge makes them bend inward. The forces causing this inward bending have to be conveyed from the centrifuge through its contents and there's a tendency for the denser items in the centrifuge to travel straighter than the less dense items. As a result, the denser items are found near the outside of the circular path while the less dense ones are found near the center of that path.
appology retracted SpydieNut said:
cjm said:
Does anyone still make wind-up watches?
Also does anyone have an opinion on something like this?
http://cgi.ebay.co.uk/VINTAGE-SWISS-OMEGA-SEAMASTE...
i think that is a lovely looking watch Also does anyone have an opinion on something like this?
http://cgi.ebay.co.uk/VINTAGE-SWISS-OMEGA-SEAMASTE...
and am very tempted to get one . there seem to be quite a few on ebay - can anyone give me an idea of what would be a reasonable price to get one for.thank you
Also interested in what its worth? Just noticed its in Singapore but has 99.9% positive feedback so muct be ok?
What does the CAL 420 refer to in the ebay ad? Is it just the design/model number?
Edited by cjm on Wednesday 23 May 17:11
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