panerai153 Posted November 9, 2012 Report Share Posted November 9, 2012 I recently bought back my Doxa 300T from a guy in Spain. Had lots of problems related to moisture damage on the dial and hands, but the movement was fine, supposedly a recently serviced movement .The movement in question is a NOS that I sent with the watch when I sold it. I took some photos, but never wore it since the hands were relumed, I set it ,wound it and put it on. Much to my surprise, I found that by 9:00 AM it had gained about 20 minutes!! What do you think. magnetized, just off, or what. Thanks Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 9, 2012 Report Share Posted November 9, 2012 I think the weekend is coming even sooner than anticipated! Okay, more seriously... my 6536 started doing that in the late 1980s after I whanged it against something pretty hard. It was running like a steam engine with a stuck throttle. I stopped in to see my buddy the Rolex watchmaker and he said it was something about a curb pin and the hairspring looped over it. He said he could take it apart and fix it and reseal it for $200, or (looking around to make sure nobody was listening) I could just thwack it, dial down, into my open palm. THWACK!! Right back to normal operation. Quote Link to comment Share on other sites More sharing options...
chris5264 Posted November 9, 2012 Report Share Posted November 9, 2012 yes....IME any huge difference in timing seems always a hair spring deal..If you can open the back.....a good shot of air, don't breath on it, will work too.... Quote Link to comment Share on other sites More sharing options...
Watchmeister Posted November 9, 2012 Report Share Posted November 9, 2012 I think the weekend is coming even sooner than anticipated! Okay, more seriously... my 6536 started doing that in the late 1980s after I whanged it against something pretty hard. It was running like a steam engine with a stuck throttle. I stopped in to see my buddy the Rolex watchmaker and he said it was something about a curb pin and the hairspring looped over it. He said he could take it apart and fix it and reseal it for $200, or (looking around to make sure nobody was listening) I could just thwack it, dial down, into my open palm. THWACK!! Right back to normal operation. Was that before or after you ran it over with a tractor? Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 9, 2012 Report Share Posted November 9, 2012 Tractor? No it's a Land Rover. Though there's not THAT much difference between them..... Quote Link to comment Share on other sites More sharing options...
freddy333 Posted November 9, 2012 Report Share Posted November 9, 2012 Could be the individual spirals of the hairspring are stuck together, which reduces its moment of inertia & causes the movement to run fast. Magnetism, oil/grime or an impact can all cause this. As chris5264 said, if you remove the caseback, you may be able to see what the problem is. The spring should be more-or-less centered around the balance wheel when stopped & you should see evenly spaced spirals. Check, too, for spots where the spring may be coming into contact with adjacent wheels (the center/2nd wheel is a prime target if the case is impacted). As a reference, this is what a hairspring may look like when it is sticking or off-center. Compare the space between the spirals at 4 o'clock with those at 10 o'clock Quote Link to comment Share on other sites More sharing options...
panerai153 Posted November 9, 2012 Author Report Share Posted November 9, 2012 Wack on palm didn't work!! Looks like it's gaining about 10 seconds a minute. I'ii take the back off when I get home and see what's going on. Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 9, 2012 Report Share Posted November 9, 2012 If the whack didn't do it, then there must a be a stuck loop in the hairspring. Freddy's right that the polar moment of inertia is reduced, but it's not intuitive how it's reduced. When one or more loops of hairspring are stuck, it reduces the effective length of the spring, which means it is more resistant to rotational torques applied by the main spring, along with having a higher natural oscillation frequency. The balance wheel won't swing out as far, and will then oscillate much faster. (for more see: Leonhard Euler's Theoria motus corporum solidorum seu rigidorum: Ex primis nostrae cognitionis principiis stabilita et ad omnes motus, qui in huiusmodi corpora cadere possunt, accommodata starting on page 122) Quick solution: pop off the back and give it a big shot of WD-40. Quote Link to comment Share on other sites More sharing options...
Watchmeister Posted November 9, 2012 Report Share Posted November 9, 2012 When one or more loops of hairspring are stuck, it reduces the effective length of the spring, which means it is more resistant to rotational torques applied by the main spring, along with having a higher natural oscillation frequency. The balance wheel won't swing out as far, and will then oscillate much faster. Well that is one way to elevate a daytona's movement's beat to match the Rolex bph. Purposely dirty it up. Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 9, 2012 Report Share Posted November 9, 2012 There's more than one way to skin a cat. Why do you think the back comes off? Quote Link to comment Share on other sites More sharing options...
freddy333 Posted November 9, 2012 Report Share Posted November 9, 2012 Why do you think the back comes off? So you can replace the battery. Quote Link to comment Share on other sites More sharing options...
panerai153 Posted November 9, 2012 Author Report Share Posted November 9, 2012 Thanks very much for the comprehensive, profound discourse in Latin(I think!!) on the hairspring theory of relativity. Considering that I don't usually use WD-40 on anything smaller than a rusty 1/2 inch bolt, I believe I will deliver the speeding Doxa to my watchmaker for a look see. I sincerely appreciate all the thoughts and wonderful advice. Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 9, 2012 Report Share Posted November 9, 2012 Thanks very much for the comprehensive, profound discourse in Latin(I think!!) Count yourself lucky I deleted all Euler's glorious equations I had originally attached! Quote Link to comment Share on other sites More sharing options...
Watchmeister Posted November 10, 2012 Report Share Posted November 10, 2012 Count yourself lucky I deleted all Euler's glorious equations I had originally attached! Actually I am kind of curious to see the equations. Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 10, 2012 Report Share Posted November 10, 2012 Here's a little. It starts on section 122 but starts to get interesting here. Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 10, 2012 Report Share Posted November 10, 2012 The best for last... Quote Link to comment Share on other sites More sharing options...
panerai153 Posted November 10, 2012 Author Report Share Posted November 10, 2012 You guys in Alaska must get really, really stir crazy during the winter. Is this what you read while you're eating your Coco Puffs and Grizzly sausage every morning? Quote Link to comment Share on other sites More sharing options...
Watchmeister Posted November 11, 2012 Report Share Posted November 11, 2012 So much for that idea. It didn't occur to me the explanation is in latin. But I appreciate the effort. Quote Link to comment Share on other sites More sharing options...
panerai153 Posted November 14, 2012 Author Report Share Posted November 14, 2012 Here's and update on the accuracy problem. I sent the Doxa off to my watchmaker, he got it yesterday at 10:00AM, wound it and put it on his bench. He emailed me last evening that it was keeping perfect time, not one second off. Emailed me again today, said it was still perfect, not one second deviation in 22 hours. Now how 'bout them apples. He probably thinks I'm crazy (Which may be true in most cases) What do you think happened? Maybe the jostling around in the mail truck, throwing the box into a bin full of other parcels, somehow jolted the hairspring and it assumed it's normal configuration, or perhaps it's like the 2846 in my GMT 6542. it ran fine while still on a bench or my kitchen counter, but put it on and move it around and it went crazy too. Turns out it had a balance staff problem.If the Doxa remains on time I might ask him to wear it for a few hours and see if it will duplicate the same problem that I saw. Or maybe if the jolting around set it straight, I'm good to go? Quote Link to comment Share on other sites More sharing options...
Nanuq Posted November 14, 2012 Report Share Posted November 14, 2012 No, this is how the Universe tells you that you have enough good watches. So send me that fricken 7924 already! Quote Link to comment Share on other sites More sharing options...
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