As we all know, our world has been deeply shaken. Lifestyles, routines and every partXa,a of our lives have been effected in some way. This is equally true for our children. Their academic and social life's have also been upended.
As a father of 4 who range in age from 15 to 24 this new reality is all too acute. My youngest two are still in high school with one a freshman and one a sophomore. They have been pretty much on their own with getting their online classes up to date and completed. My daughter, who is also my youngest, has been on task the entire time, she had finished her work last week. My 17 year old son has procrastinated much of the entire time. 4 weeks ago he was in danger of flunking. So, as an incentive, I offered to get him his favorite watch which is a duplicate of mine if he finished with at least a C average in each class. In this case, it's a 1978 Timex Falcon Eye. Thankfully I had found one for an absolutely fantastic price, a steal to be honest. When it arrived, it was pristine!
Tonight was his final night. The final assignments were due. He plugged away and by 9:45pm, he crossed the finish line! And as required, no class was below a C grade point average. In fact, only one was a C, the rest were comfortably within B and A averages. I'm very proud of him and it was a Thrill and an honor to present his watch to him. For fun, I had him put on his new watch but told him he was trying on my watch to see how victory feels. He was all smiles and kept saying how awesome the watch is. Then I held up mine on my wrist and put it next to his and said, yep, it's almost as cool as mine! He was like, What!? Is this mine? No way! He was so excited! Totally worth the wait.
Here they are, two of the finest original 1978 Timex Falcon Eye's you'll likely ever see!
Pictures don’t always help so I always use these compartment trays, these I get from a hobby store in the paint section. But Esslinger sells nice ones with lids....each piece I remove goes into one compartment with its respective screws. Each compartment represents a step. When i reassemble I work backwards. As far as a bridge that uses different length screws you can always attach the bridge and look from the sides and tell where longer screws will go. Or by seeing where they screw in from under. Kinda hard to explain but just observe and you will get the picture.
I have been practicing watch servicing these past months. So far I have successfully serviced a ST36 (ETA6497 clone), thanks to Mark's watch repair course which is awesome! I have also tried to service a NH25A, and messed up the hairpsring (replacement on the way), and a Miyota 8215. Everything was going well with the 8215 until I reassembled the train bridge and noticed that the escape wheel wobbles when I turn the wheels. My guess is that I accidentally broke off the upper pivot during cleaning. I was looking for a replacement escape wheel and found it at Cousin's, but they are out of stock. Anyone know any other place I could get one? Thanks.
PS: Trying to keep a positive attitude after messing up two movements, but practice makes perfect. :)
Don't think of it as math so much as relationships. F=KX is (F) Force equals (K) spring k/constant times (X) displacement. You're only really worried with how they relate to each other, not anything more precise. If you multiply numbers together, the result is bigger; if you divide them, the result is smaller. The end.
Force is exactly what you think it is. Displacement is a fancy word for distance. The spring k/constant is how stiff the spring is. For watchmakers, the important part here is that we can split apart the mainspring into component parts of stiffness (*) and distance (effective length; effective, because it's typically preferred that a spring is never fully wound or unwound for better isochronism).
* Stiffness in a mainspring is typically a function of its thickness, but if you have a really old coil mainspring vs a modern S spring, or an old school spring steel vs a modern alloy, or maybe the spring has set, these can all play a part.
The gear ratios in a gear train are fixed. For every release of the escapement, a certain degree of rotation of the mainspring barrel is unwound from the mainspring. That makes analysis even easier, because X is constant per beat. You simply get more X with a longer spring in the form of more beats.
Assuming everything else is in proper fettle, you have a finite amount of room in the mainspring barrel into which you can stuff a spring. That stuffing happens across the dimensions of length, and thickness; dimensions that correspond directly with X and K respectively. If it's too strong, the balance over banks, and you gotta problem. Additionally, but to a lesser degree, if your amplitude is higher than is required for isochronism, it's really not doing you any good, and is just a waste of spring. Too weak, and amplitude is low, and error creeps in (anisochronism). So you need a spring that is stiff enough to get you a good enough amplitude to ensure isochrony, but otherwise as long as you can to maximize power reserve.
If everything else is good, then you add a new mainspring which measures .007 thicker and feels harder (aka stiffer or higher K) and is .05 shorter (lower X), that's the precise recipe, according to Hooke's law, for a good amplitude but short power reserve. You made K larger, and X smaller, you just don't know the precise magnitude of each change...
You can see through your amplitude that F is larger than would be expected for a given distance of mainspring travel since, per swing of the balance, X is fixed, that means K is higher than it should be. You can further see through the short power reserve that the overall X of the spring is shortened.
312° is a really high amplitude; probably higher than just about any manufacturer requires for isochronistic reasons... On top of that, It sounds like Citizen kinda sucks for documentation, but they seem to be in the same school as Seiko who is good with documentation, and is known for preferring unusually low amplitudes while still achieving reasonable isochronism. Given that the point of a high amplitude is to mitigate anisochrony, they're going at the isochronism problem from a different angle (whatever that is, I don't know yet). I would shoot for a typical Seiko level amplitude, see how the power reserve comes out, then check isochronism against your preferred/available of spec or personal standard.
This has nothing to do with braking grease, internal barrel features, bridle wear, or anything else. Just the isolated variables as described. Also worth noting, this is how Roger Smith (George Daniels' protegé) chooses mainsprings for his highly esteemed movements according to... him in his own lectures**. Also also worth noting... I'm about as nooby a noob that ever noobed, so consider the entire manifesto above in that light.
Bottom line: Get a new mainspring that's thinner and longer. Since the alloy appears to be different, you may go more than a single step thinner, and see how long you can go and still functionally fit in the barrel. This, again, is inferred from the Roger Smith lecture, and he specifically states that he has a huge assortment of mainsprings at his disposal**, so YMMV.
**I think this is the lecture, but it's not exactly the key focus, and was really just a side note at some point... I don't remember where in the hour and change it came up or why, I'm just one of those people who remembers trivial details like that...