High positional error

[spectre6000]

I recently took a swing at an EB 8800. It wouldn't run at all when I got it, and I figured I couldn't make it any worse. The lever was very sticky and didn't like to pivot so much that I initially thought it had been installed upside down or something. At any rate, I broke it down, cleaned it up, and put it back together, and was surprised when the balance immediately kicked off like nothing was wrong! I was able to regulate it to 0 beat error and 0 seconds/day in the dial down position. Then it was late, and I went to bed ecstatic at finally not butchering a movement. It lives in a watch that is ugly as sin, has no stem/crown, and the mainspring has a bend right at the hook, but it ran. 

Last night, I figured I should probably check on the positional error before spending any money on a new spring, crown, and stem. Good thing. About a 100 second/day swing across positions. The hair spring doesn't look as bright and shiny and perfect as I'd want a hairspring to look. In fact, it was initially pretty far out of plane. Am I correct to attribute the positional error to hairspring irregularities?

[Nucejoe]

EB 8800 came in 1/7/17 jewels versions, which one is your watch?

I can't figure out, what in the sam hill where they thinking to make the one jewel variant and claim concern about positional variations too. 

As for your concern about hairspring material degredation, unfortunate as it might be, it simply sounds like an unchartered territory, 100s/d  doesn't sound like a fouling hairspring either. 

Good luck pal.

 

[nickelsilver]

If you're going to start doing precision timing the watch has to be in perfect condition. If a whole bunch of things seem pretty good you'll be chasing your tail.

Definitely an out of true hairspring can cause problems. It must be true, in the flat, round, and same at the collet. If that's good, and the escapement is correctly adjusted, regulating pins gapped correctly and spring centered in them, pivots particularly of balance, fork, and escape wheel perfect, and all else is good, you can start hunting what might  be a poise problem.

 

If this is a one or 7 jewel watch (thanks Joe), get your hairspring adjusted as well as you can, close the regulating pins (I bet they're wide open), and be happy if it's around 60s delta.

[rodabod]

Getting healthy amplitude? These movements can manage pretty good positional variation when running well. 

[spectre6000]

It's the one jewel variety. No shock protection. Whatever other options or features they came with, it doesn't have that. Doesn't even have a seconds hand. Bottom of the EB 8800 barrel.

What is "precision timing" exactly? I'm not expecting anything crazy accurate, but a 100 second swing between positions seems excessive. This is the first watch I've gotten this far, and I've honestly never paid much attention to the cheap jewelless watches or their accuracy. I've been scooping up 404s to practice on, and this was a bonus watch in a lot of 3 1/2 I got for a dollar or so; I genuinely had 0 expectation that it would be salvageable. It wouldn't tick at all, didn't even have a stem, and really ugly. I was thinking in terms of Russian type accuracy.... Which I just looked up, and the spec on a new Amphibian is -20/+60... So that's an 80 S/day swing... Maybe my problem is expectations.

Win! It's not open in front of me, but unless I'm mixing up movement memories, I'm 99% sure the regulating pins are as closed as they get. 

Amplitude is excellent. Best I've ever had on a watch without rebanking.

[nickelsilver]

5 hours ago, spectre6000 said:

 

What is "precision timing" exactly?

 

It's when you push a watch to its limits of rating. On something like this, which is a pin lever movement with one jewel, you can't do that much, as it's a piece that's been made to a price point and there just aren't that many things you can retouch. You could probably get it closer than 100s delta, if it's running really well. Like if you are seeing this excellent amplitude in the dial down position, if it's close to the same in dial up, and then the drop in amplitude isn't more than 40 or 50 degrees going to vertical, you might get it better by getting the hairspring spot on and then possibly even doing some poising.

 

But it would be time better spent learning such things on a jeweled watch with lever escapement. Something big and stable like a 6497. In a watch like that you have a real cause and effect, and can see the results of your actions unambiguously. With lower grade movements there are so many compromises already made that you are limited and things might not respond to what would be considered a correct correction on something higher grade. So you might have taken good advice here or from books, apply it to your EB, and nothing or the opposite of what you wanted happens- but you don't know if you did something wrong, or it's just how it is. The simple fact that this probably has a Nivarox grade 5 hairspring would make it hard to adjust (1 is the best, and there is a real difference in performance between the different grades- 5 being the worst).

[JohnR725]

10 hours ago, spectre6000 said:

What is "precision timing" exactly? I'm not expecting anything crazy accurate, but a 100 second swing between positions seems excessive.

Precision timekeeping is an interesting term of just basically meaning the watch keeps good time. But unfortunately there is a little more that needs to be done than moving the regulator and worrying about the poise of the balance wheel.

I Have some PDF examples. As you're aware companies like ETA have their technical service bulletins but they also have had what they call manufacturing information. I always find these quite fast Fascinating because it has all the technical stuff usually missing off the other one.

If you open up both PDFs and you scroll down you'll find that both grades, and multiple of qualities basically. Like for instance the 7750 as three of them labeled Elaboré, Top And Chronomètre. Then the 6497 only has two different  ones. So if you look at the less you'll notice that in the case the 6497 there basically almost identical other than me get to the bottom they've regulated one of them better and they time it in one more position. On the 7750 you'll notice that there's a lot of differences besides the timekeeping. They're using better and better materials. Then of course are timing and more and more positions or verifying basically that they keep time in those positions.

What becomes interesting when you look at these is for instance the 6497 can be regulated to keep better time. But if you notice it's timekeeping versus the  7750 it will keep better time because it's materials that they used are better.

The simplistic of this is better timekeeping requires better everything. A jeweled lever escapement versus a pin lever escapement is an improvement. All the materials related to the balance wheel. Then just the time and effort made to adjust things is going to be better than a watch that was made to be inexpensive. You can still spend some time making it better but there's a limit of what you're going to do.

 

 

 

ETA 6497-1 Manufacturing Information.pdf ETA 7750 MANUFACTURING INFORMATION.pdf

[Nucejoe]

EB, Ebosa and bunch cheap watches made back then, put Oscillators in their watches which Dr ranfft calls "perfect immitation of screw balance" in that, there appear to be screws on balance rim from top view, but you discover its anular when you view the other side. 

I put together an EB1197 out of scrap parts, happen to have a NOS balance complete which I installed and am surprised with the rate of 5 to8 s/d( thats if friends TG is healthy)  but I know COSC will kick me in you know where if I was to candidate EB1197 piece for precision test, it just wasn't built to deliver precise timing, you can expect that out of a high grade multiposition adjusted piece. 

I think I am having fun with your experimenting that ole EB8800.

[spectre6000]

Well... Like I said, I honestly did not even expect it to run. The balance moved reasonably freely, but it wouldn't tick a single tock, and given my failure rate thus far... I was really just going through the motions (disassemble, clean, reassemble, oil) out of habit.

If it's not capable of much better than the timing I'm getting out of it in the first place (no second hand or minute marks), I think I'll give the hairspring one more hard look, then maybe just regulate it the best I can, get the stem, crown, and mainspring required to finish the job, and sell the watch as a complete watch (maybe there's a leprechaun pimp out there sporting bellbottoms in need of some bling?). I'm really just trying to make this hobby self sustain, and if I can buy more 404 club members with this one, I've met my goal. Score! I will have actually successfully serviced a watch! (Right?)