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Your opinion/advice on my Doxa 115 (ETA 2451) timegrapher readings


BennyE

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Hi all,

As a start, you may want to read my quick introduction here :)

I did a full strip-down of this movement and properly cleaned its parts with lighter fuel. Before the "service" (if you can call my first real service of this movement like that) the amplitude was at 160-170°, which wasn't exactly great and the watch gained around 60-70 seconds a day (according to the time grapher).

I tried to follow all the good advice from the watch repair lessons, wore e.g. finger cuts which was quite difficult in some situations. In general, I'm quite happy with the result. The movement looks clean and everything was smooth (e.g. train of wheels) when I assembled it. However, the result is not yet good on the time grapher.

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Coming to my issue with this movement, it looks weird on the time grapher where the amplitude travels between 190° and 240° and without touching the watch the watch moves between losing/gaining -35 and +40 seconds/day "in waves" on the time grapher.

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Full disclosure on the issues that I had (and introduced myself):

  • I scratched the hour hand, I know that this is not acceptable, but nothing I can do now apart from trying to polish it when I reassmble it (it is my watch anyway and I don't wear it, but still not acceptable)
  • I damaged the upper pivot of the pallet-fork during re-assembly and therefore acquired a scrap ETA 2451 (Dugena) movement from eBay as an attempt to find a replacement pallet-fork. This wasn't successful, as this damaged movement also included a damaged pallet-fork thus I bought a new pallet-fork for ETA 2451 via eBay (I currently don't have any way to order at Flume, as they only sell to corporates/business, not private persons)
  • I wound the mainspring in by hand and honestly this wasn't something that went well. I've already tried numerous times to get hold of a mainspring winder, but they're quite sought-after on eBay and up their price in the last seconds of the auction by exponential means
    • The issue I had with the mainspring was, that I didn't do this before and I first tried to wind it by hand and hold it by hand and later on put it into the barrel fully wound. This wasn't only very exhausting, but the skin of my fingers (yes, I couldn't use finger cots at this attempt - as it drove me nuts) at thumb and index finger started to be injured (at least you see, there is a lot of passion :))
    • The attempt afterwards was more successful where I cleaned the mainspring again and wore finger cots and wound it into the barrel directly starting at the outside walls
    • Note that the mainspring didn't look very good, when it lay on my workbench (it looked "too set") which was likely caused by my first winding attempt
  • The balance pivots (incabloc endstones) are not lubricated yet
  • In general the lubrication looks much more simple job when I watch the videos by Mark (I take it as a positive, that the amplitude reading is better after my service)

Lubrication:

  • I used Molykote DX on the clutch of the keyless works
  • I used Moebius D5 on the heavier friction points
  • I used Moebius 9010 on the more delicate friction points
  • I haven't lubricated the pallet-fork pivots
  • I didn't (yet?) lubricate the entry & exit stone with Moebius 9415 (ETA 2451 is only a 18000 bph movement)
  • I didn't lubricate the balance / incabloc settings yet (this is what I'll do next)

Now that you know the issues that I'm aware of, the following is my list of things that could cause the issue I see on the time grapher. I'd like to hear your opinion/advice what you believe could cause this weird reading.

  1. Magnetism, I should demagnitise the watch movement (which I currently can't, as I don't have a demagnitiser yet - am about to acquire one via Amazon)
  2. I might have damaged a wheel during cleaning (all looked good to me) and it doesn't run evenly good, depending on the position in the train of wheels
  3. The mainspring is causing this issue, as it doesn't provide "steady power" and thus causing this issue (I'd more expect an issue with the power reserve though)
  4. The beat error is too high for my taste, but I have difficulties to adjust it (I'll look at this in detail again, it is not the source of the timegrapher waves in my opinion)

Some words on the movement:

  • The Doxa 115 is a 11 1/2"' movement, soley based on the ETA 2451 (I didn't find any difference, when I looked at the scrap Dugena ETA 2541 movement)
  • The movement runs at 18000 bph and the automatic appears to wind it in both directions (as far as I can tell)
  • The mainspring is this one ZF-869 which I'll try to get hold of to replace it
  • I guess that this movement has been discontinued as you need to fully disassemble it to replace the mainspring, so it is not as service-friendly as later more modern movements (However, I do this for the fun of disassembling it, therefore I don't care that much :))

I'll update here when I've lubricated the incabloc setting endstones, but I don't expect to see an improvement. (Hopefully, I'll be proven wrong by myself ...)
I also noticed that the movement might be under tension due to the winder/stem being pressed into it by the time grapher, will check if this makes a difference.

Have a good weekend! I hope you liked this post :)

Thanks,
Regards,
Benny

 

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The loose/ gain is expectedly periodic. Give the period.

The change is said behaviour in differnt positions?

Staffs axial play, any side shake? How well cab locks keep the jewel in place?

These and more, before suspecting faults due to lubrication.

Regards joe.

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Hi,

Thanks for your feedback. I just finished doing so (as I also wrote) and I'm really impressed by what magnitude of a difference it makes. I thought it would be better, but that a dry balance causes such a big difference was out of my imagination.

I'd like to thank you for taking the time to reply, it was the good thing to do.

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I'll monitor it for a bit .. :)

Thanks again,
Regards,
Benny

 

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I doubt seriously if oiling helps identify the cause.

The period of loose/gain you speak of,  is reasonably indicative of possible fault in power train gears , it  may corresponds to the period of the wheel exactly or subperiods thereof, caused by bad or unclean gear teeth and the like.

In case the period inconsistancy notably change behaviour at different poistion as well, especially face up, down or oblique positins, other causes join in.

Regards joe

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I'll point out that I work with a young-ish watchmaker who's probably in the top .01% and several times he's been banging his head against the wall on a prototype and gives it to me, I check and his balance pivots are dry as a bone. He never does it in a repair though. Anyway you're in good company- but do oil everything before checking (well, what gets oiled) and let it run for a good 24 hours.

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Good job... that’s how one gets started. Obviously it’s not cost-effective but keep at it and it will eventually.

My first observation is the cleaner used to wash the movement. There are multiple sources that show how using lighter fluid can really hurt you. Even if you don’t notice it, it may be leaving some residue, and if this is the case here and there, this could partly explain why your gear train has uneven resistance and thus the amplitude and rate vary so much.

Add to that the out of poise mainspring, and the wild variations start to make more sense.

Not oiling properly before timing is not a good idea but even then, I wouldn’t expect the significant variations you’re obtaining. Something to think about. It’s a good idea to let it run 24 hrs before doing more definitive timing measurements.

The demag is a big deal. It should be the very first step before you even touch the movement. You should time the watch first thing, demag retime and then overhaul.

Looking forwards following on your progress. Keep it up!

Cheers!


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@Nucejoe the reading on the time grapher was throughout a few minutes, not hours or days. After oiling the balance, it looks much better

@jguitron Ok, so I'll not use lighter fluid any more. Is Würth Brake Cleaner a better alternative? I thought that it is good enough, if I clean everything with pegwood afterwards. I do have a small ultrasonic bath, but I don't have the good cleaning liquids apart from lighter fluid & brake cleaner. If I'm leftover with fluid that is harmful for water, I'll have trouble to get rid of it afterwards.

 

 

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[mention=4872]Nucejoe[/mention] the reading on the time grapher was throughout a few minutes, not hours or days. After oiling the balance, it looks much better
[mention=2432]jguitron[/mention] Ok, so I'll not use lighter fluid any more. Is Würth Brake Cleaner a better alternative? I thought that it is good enough, if I clean everything with pegwood afterwards. I do have a small ultrasonic bath, but I don't have the good cleaning liquids apart from lighter fluid & brake cleaner. If I'm leftover with fluid that is harmful for water, I'll have trouble to get rid of it afterwards.
 
 




Sure! I’m not familiar with that solution but it’s formally a cleaning solution.

Pegging is a good idea although it doesn’t come without a big discussion that can be found in other rooms... Now, that’s great for pivots and jewels but pinions and wheels may still retain some residue.




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I'm curious about how you're holding the watch in the microphone? So I snipped out the way you're doing it and I have a sample of the way it's supposed to be done so is there some reason why you're doing it this way? Then I noticed the other way you're holding it where it appears to be your pushing on the crown? The jaws of the timing machine are quite strong pushing hard on your crown which is pushing on the stem isn't really a good thing to do.

So many questions and so many problems.

Then it's amazing how much power is lost through the gear train and escapement if it's not properly lubricated. Then totally wrong lubrication can be worse than no lubrication at all neither of which is desirable if you're trying to get your watch to run properly.

The beat error? I'm attaching an image same timing machine different watch so you can see what 2.2 ms looks like. Your lines look like they're too far apart for the error they're producing? Then from the link below is references that later versions of this watch have a floating stud? If that's the case putting this watch in beat should be really really easy.

Mainspring someday you'll have to put breaking grease on the barrel wall but that's not going to be an issue or problem right. Modern new mainspring are prelubricated it's an invisible lubrication unfortunately for the most part. But as you've cleaned the mainspring it now no longer is lubricated you probably should put some lubrication on it. From the list of lubricants you currently have you could use D5 on the mainspring. Then your description of it doesn't look too good? Everything you do to screw up the mainspring ripples down to the balance wheel. Besides the usual cone shape that you get from hand winding were there any kinks or bends in the mainspring?

Then when timing more than one position is desirable. Your currently resting on the end of the balance pivot the least amount of friction so at least one pendant/crown position is desirable. A wristwatch crown down works fine.

Cleaning fluids lighter fluid seems to be popular on this group. There are alternatives at the hardware store. It's important to remember no matter what you are using is it's not a one step process. This means that whatever you clean the watch in you now need to Rinse at least twice. Each rinse needs to be cleaner than the previous one. So the initial cleaning fluid whether it's commercial watch cleaner whatever puts things in the solution which is now coating everything in the watch. Then the next rinse reduces that concentration and the rinse after that will reduce the concentration.  Then you don't have to go through a lot of cleaning fluid or  rinse if you keep them in jars/Containers with tightfitting lids.

 

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&ETA_2451

weird use of pickup.JPG

proper way to hold watch.JPG

timegrapher 1000 2.2 ms.JPG

pushing on the stem.JPG

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@JohnR725 Good observation there and I'm sure this is part of the issue I observed. I haven't had the time to get back to my watch yet - need to do some work. I didn't notice the notch yet, in which you installed the movement - will try that out. Thank you.

I usually installed the watch like that, when it was cased in, but then the case supported the overall structure of the watch and reduced the stress/tension on the stem. I agree that this wasn't my brightest moment, but fortunately I noticed it myself as highlighted above.

Thanks again all, appreciate you took the time to share your guidance with me.

Benny

 

 

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