Cyma 571 performance issues (alternate titles: Watch from Hell, or Tar Baby)

[LittleWatchShop]

Believe it or not, this has been on the bench for close to a year.  During that time I have fixed many watches, but this one is killing me.

I destroyed the hairspring at the beginning of this adventure and as best as I recall, I broke the staff (or it was already broken)--this journey has been so long!!

I turned a staff for it (I posted about this a long time ago).  I found a donor hairsping and balance wheel.  I installed a new mainspring.

In addition, I have polished the pivots of all wheels. I have removed some of the timing screws...added some timing washers to the remaining ones to achieve better balance.

Granted, through this process, I have been operating (or attempting to operate) above my pay grade, so be nice to me.

Here I am showing some free-wheeling videos.  I started the balance with a full 360 degree rotation and then released.  Seems to me that the balance should oscillate longer.

You will notice that the balance is slightly out of round.  I have tried to remedy this and have improved it some.

I believe that some previous watchmaker messed up some things.  The roller table appeared to be crimped on to the staff.  It just came apart and I replaced it from a donor.  Also looks like the pallet fork bridge was sanded down, perhaps to keep the balance from hitting it (due to an incorrect staff??).  I have made sure that the hairspring is not rubbing against the stud, nor anything else.  It is a breguet and is in good planarity.

I am at the point of re-staffing again.  This time, I have (or think I have) a factory 571 staff.

These problems are hard to troubleshoot over the web...I know.  Any help on next steps appreciated.

Here is one video.

I will post another shortly.

 

Here is a slow motion.  Not sure why it is not crisper.

[mikepilk]

I test the balance by giving it a strong blow from a puffer - my criteria is that it is still oscillating well after 30s.

Your test is more repeatable as you are starting from the same point. But it stops after about 25s - that's not good.

How much end shake is there? Are the coils evenly spaced when looking from above?

 

[JohnR725]

13 hours ago, LittleWatchShop said:

In addition, I have polished the pivots of all wheels.

Was it necessary to polish all of the pivots?

13 hours ago, LittleWatchShop said:

I believe that some previous watchmaker messed up some things.  The roller table appeared to be crimped on to the staff.  It just came apart and I replaced it from a donor.  Also looks like the pallet fork bridge was sanded down, perhaps to keep the balance from hitting it (due to an incorrect staff??).  I have made sure that the hairspring is not rubbing against the stud, nor anything else.  It is a breguet and is in good planarity.

Yes the fun of trying to figure out why someone in the past did the bizarre things they did and what problem Did they perceive there were trying to solve. Then of course what problems of the introduced by changing and modifying things that perhaps you are looking at because no one ever changes or modifies those things typically.

13 hours ago, LittleWatchShop said:

These problems are hard to troubleshoot over the web...I know.  Any help on next steps appreciated.

I always like to see a timing machine result?

Then what exactly do you perceive the problem to be? What is the definition of a performance issue?

[LittleWatchShop]

2 hours ago, JohnR725 said:

Was it necessary to polish all of the pivots?

Probably not.

2 hours ago, JohnR725 said:

I always like to see a timing machine result?

After my next iteration, I will post some results.

The problem with letting a watch linger off and on for so long is I forget everything I have done.

This morning I measured the length of the staff and it is a little short.  Supposed to be 408 and I measure 398.  Again, I cannot recall if this is the staff I made or one I acquired--probably the former.  So, I am going to re-staff it today (that is the plan).  Anyway, the pivot length is probably affecting end shake as mentioned in one of the responses.

[rehajm]

9 minutes ago, LittleWatchShop said:

The problem with letting a watch linger off and on for so long is I forget everything I have done.

True dat. Despite copious notes the lead time for parts is a killer for me as well...

In my humble limited experience opinion: just looking at the behavior of the oscillation I think you may be on the right track. Assuming the wheel is flat and reasonably poised...do I see a wobble what looks like rotational center is moving around excessively? Pivots too short or too narrow? I'm working on an A-11 what looks like that- a good looking Breguet and good energy from the train but...anemic. I'm waiting for life to stop getting in the way to replace the staff (of course with Waltham I'm just guessing at the appropriate staff size)...

[LittleWatchShop]

An update.  Carefully looking at the pivot on the roller side, it seemed that the shoulder should be recessed a little more.  The picture I show may make you think otherwise...no analytics here...just a hunch.  So I chucked it up on the lathe and took a little bit off the shoulder as well as polished it some.  The result was dramatic.  My free-wheeling test lasted well more than a minute.  When I assembled the escapement, I got about 50 degrees more amplitude.

I am guessing that the shoulder was rubbing (ever so slightly) on the base of the jewel.

[mikepilk]

The top of the roller looks very close to the pivot, and it may be the pic, but is the top of the roller flat? Could it be touching the jewel setting?

[LittleWatchShop]

2 minutes ago, mikepilk said:

The top of the roller looks very close to the pivot, and it may be the pic, but is the top of the roller flat? Could it be touching the jewel setting?

The top of the roller is flat.  I have observed, under high magnification, that the roller table does not touch anything.  I think the touching was at the shoulder of the staff.

Bear in mind that this is a staff that I turned from raw stock, so you have an amateur operating at the edge of the bell curve (or attempting to do so).

[mikepilk]

I admire you for being able to make a staff. I'd love to try.  If only I had room for a lathe 

(You have all the room there in Texas @LittleWatchShop - about 3x the land area of Britain and 40% of the population. Could you send some spare room over please ) 

Edited June 28, 2023 by mikepilk

[LittleWatchShop]

10 minutes ago, mikepilk said:

You have all the room there in Texas

LOL...yes we do.  And I have 15 acres where I am sitting now.  But for every additional square foot of living space I would add, the taxing authorities start licking their chops--anxious to pounce and charge more ad valorem tax!!

[JohnR725]

11 hours ago, mikepilk said:

I test the balance by giving it a strong blow from a puffer - my criteria is that it is still oscillating well after 30s.

The other thing when doing a test like this is the same as timing machine tests more than one position. I love her style up and down should be identical and turn it sideways obviously that will be less but it's necessary because as worth thinking here one pivot might be a little short so in one direction it looks great to another it doesn't.

Oh and yes sometimes if you leave the watch on the bench long enough maybe I'll just go away. One of the items on my bench because we couldn't get parts customer finally just gave it to us. Which isn't particularly helpful because we still need to get the parts which will probably have to be custom-made. Another item on my bench went away to the other watchmaker he volunteered he wanted a challenge. So occasionally stuff will disappear if you ignore it long enough otherwise it's the nightmare that never goes away we all have those. At least until some that gets done and goes away but I sometimes wonder if some projects may never go away.

[LittleWatchShop]

23 minutes ago, JohnR725 said:

The other thing when doing a test like this is the same as timing machine tests more than one position.

Certainly.  And I am seeing issues in different positions.  Miles to go before I sleep.

[JohnR725]

4 minutes ago, LittleWatchShop said:

Miles to go before I sleep.

I would try to be careful with that one I continuously screw up my sleep And I can tell you it's a not a good thing.

[LittleWatchShop]

Here are a couple of pictures of the jewel on the balance cock.  Clearly an issue.

If I can find a jewel, I will replace it. 

Is it a friction fit jewel?  Which way do I press it out?

[LittleWatchShop]

I found a replacement jewel.  It is running better now.  Still not great.  More work to do.

FYI, my dad had a little box of "pocket watch jewel assortment." Found my replacement in the little box!

[mikepilk]

47 minutes ago, LittleWatchShop said:

I found a replacement jewel.  It is running better now.  Still not great.  More work to do.

FYI, my dad had a little box of "pocket watch jewel assortment." Found my replacement in the little box!

I bought a mixed selection of jewels and have managed to find a match to broken jewels quite a few times.

[LittleWatchShop]

Update---

I got to wondering about the mainspring I replaced.  Found it on ebay and was said to be for Cyma 571.  Well, I pulled it out and discovered that the strength of the replacement was less than that of the one I removed.  So I went to Bestfit where I found the following Dennison size: 6x7x16.5. Converting the first number to metric yielded a thickness of 0.15mm.  When I measure the replacement, I get 0.14mm.  The original measures about 0.17mm.  The width of the original and replacement match the Bestfit Dennison value.

So I have weak power!  Off to find the correct mainspring.

Edited July 12, 2023 by LittleWatchShop

[RichardHarris123]

According to Ranfft. 

[LittleWatchShop]

5 hours ago, RichardHarris123 said:

According to Ranfft. 

Yeah, I saw that.

[mikepilk]

From GR database

Yet Cousins have :

Edited July 13, 2023 by mikepilk

[LittleWatchShop]

Maybe I should just take an average!  Going for a stronger spring because that is the direction I need to go!

[LittleWatchShop]

Rather than start a new thread, I will continue on this one because it is the same watch.

I have made several staffs for this watch--to specification that I have.  Been plagued with poor performance.  I concluded that the balance wheel is ever so slightly rubbing the pallet fork bridge/plate.  Obvious from DU and DD performance.

Some time back I found a NOS balance complete for the watch, but it was not a breguet hairspring (the 571 comes both ways).  A long time ago I was going to fit a breguet HS to the NOS balance but the HS collet inside diameter was too big.  I worried about closing it with a concave punch.

This week I received my Bergeon collet closing tool, so today, I closed it to fit on the NOS balance wheel.  All was well except the rubbing on the pallet fork plate was the same as before.

I am posting some pictures of the pallet fork plate and asking for opinions.  It appears to me that some previous watchmaker tried to file it down...perhaps to fix the rubbing issue.  The previous watchmaker bodged up the roller table, and replace the upper balance jewel with a 15 rather than 13 hole size.  So, I know a lot of hacking has gone before me.

Clearly, the color of the plate on the top is brass whereas the rest is silvery as is the rest of the plates on this watch.  I think it has been filed down.

Thoughts?

I have a mind to file it down more since it has already been "modified."

[LittleWatchShop]

This morning I measured the NOS balance complete and the dimensions from the balance arm to the end of the pivot on the roller side are right on.  I am perplexed.

I am going to cut another staff this morning and make the roller side longer by 10/100 mm.  Here we go again.

[dadistic]

Isn't micro-machining fun? 

 

[StickDog]

Another effective and safer way to close a hairspring collet is to put it in a close fitting wire chuck in your lathe and then just slowly and carefully tighten the chuck as far as you judge necessary.