Centre wheel not flat, rubbing on barrel. Best course of action?

[fellerts]

Hi all,

I'm working on a lovely Longines "Flagship" that houses a Longines 284 movement. The watch was last serviced in '94 and I know for a fact that no amateurs have been poking around in here. The watch was running when I got it, but all the oil had crusted up and it needed a service. When disassembling, I noticed an interesting wear pattern on the dial-side of the mainspring barrel.

In this movement, the centre wheel sits below the mainspring barrel. This wheel apparently has a slight bow to it and has obviously been rubbing on the barrel. I can also feel them binding if I assemble the barrel and the centre wheel and turn the barrel with some pegwood. It's hard to photograph, but I've tried:

You can see where some of the teeth have been grinding against the barrel in this photo:

Here they are in-situ, looking down from the dial side:

I have a few questions:

1. Is it possible that this happened in "normal use", or is it more likely that the watchmaker slipped up back in '94 and bent this wheel? I can't imagine a force that could do this to an assembled movement.
2. How would I go about flattening this wheel? I do own a staking set, but I have practically zero experience using it. Are there any resources out there with pointers on how to perform such a repair?
3. I may have to replace this wheel entirely. I went to julesborell and found the movement: http://www.julesborel.com/s.nl/it.I/id.7/.f which lists the centre wheel as " 201/LON 280". scotchwatch.com seems to have a "Lon 10.68Z center wheel #201" in stock here - would that be a match, or have I veered off course? Any suggestions or pointers to where I can find a replacement are welcome.

cheers,
Fredrik

[watchweasol]

Hi. It is possible the previous repairer slipped up , because if he had noticed it I am sure he would have straightened it.  It is possible to straighten them in much the same way as trueing a balance.  De Carles boo shows one being straightened on an anvil with a large circular punch/ drift.  You will need probably a depthing tool to check it afterwards for flatness. Try that first you may surprise yourself and get it right.

[rehajm]

I must say that is a nice looking pattern...reminiscent of the 'Spriograph' toy...

[watchweasol]

Hi you remember them !,  

[JohnR725]

2 hours ago, fellerts said:

no amateurs have been poking around in here.

I'm interpreting you think that amateurs are poor at doing watch repair and professionals are good? But oftentimes amateurs can spend way more time on the watch because they don't have a money factor that may be a personal project that they will spend lots of time on. Whereas so-called professionals have time and money constraints. Or basically you can't tell whether a professional is going to be any better or worse than an amateur or hobbyist for that matter.

2 hours ago, fellerts said:

centre wheel as " 201/LON 280". scotchwatch.com seems to have a "Lon 10.68Z center wheel #201" in stock here - would that be a match,

I'm having a minor confusion here? If you click on their part you get the cross reference it appears only cross reference to almost nothing but somehow you've made the connection that it's equal to

This watch and if you look up this watch the database it has almost no parts listing?

2 hours ago, fellerts said:

"Lon 10.68Z center wheel #201"

I really curious how you figured out that this exactly cross references? Because I'm not seeing it so I'm a make a guess are you looking at the part number 201? A classic mistake that people make is failure to grasp Swiss watch part numbers. You need at least for the older system to separate numbers you need a model number and a part description number. Like 201 tells us this is a center wheel. For instance here's a page snipped out of the bestfit book

The part numbering system probably came up because parts are packaged in little tiny packages And this way didn't have to print names plus you wouldn't have to print names in a variety of languages you to just print a number like 201 and everybody would know That is the center wheel.

Oh and if I physically compare your watches I'm guessing the center wheels do not interchange wishful thinking of that part 201 will substitute for all the watches we've all had that wish unfortunately it doesn't seem to work out.

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Longines_284

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Longines_10_68Z

2 hours ago, fellerts said:

In this movement, the centre wheel sits below the mainspring barrel. This wheel apparently has a slight bow to it and has obviously been rubbing on the barrel. I can also feel them binding if I assemble the barrel and the centre wheel and turn the barrel with some pegwood. It's hard to photograph, but I've tried:

Looking at your pictures I wouldn't even try to fix this and see if you can find a replacement center wheel. The unfortunate problem of quality control can't catch everything and isn't really a problem except over time.

This is where if you look at documentation from other companies like Rolex and Omega you'll see where if they had a design that wasn't quite right they will typically upgrade. The recommended replacing certain components to solve problems. So we don't know how common this problem was or whether there was an upgrade or not but the easiest fix we just get a new center wheel.

 

 

 

 

 

[fellerts]

23 minutes ago, JohnR725 said:

curious how you figured out that this exactly cross references? Because I'm not seeing it so I'm a make a guess are you looking at the part number 201? A classic mistake

You’re right John, thanks for clearing that up. Good to know!

24 minutes ago, JohnR725 said:

where if they had a design that wasn't quite right they will typically upgrade

interesting, do you mean they update the design for some parts and recommend that watchmakers replace them when servicing?

seeing as I have nothing to lose and lots to learn, I’ll try my best to make this wheel flat. Failing that, I’ll look around for a replacement. Apart from eBay, do you have any suggestions for where I might look?

[watchweasol]

Hi  you could try Speedtimerkollection.com  in Europe for parts   or Welwynwatchparts.co.uk both suppliers of  second user watch parts.

[JohnR725]

4 minutes ago, fellerts said:

interesting, do you mean they update the design for some parts and recommend that watchmakers replace them when servicing?

Vintage watch documentation is interesting as is printed on paper. Before the days of PDFs paper documentation got scanned by watchmakers possibly some material houses for parts identification. Typically servicing was not scanned. So often times when you're looking at the technical literature you'll notice that a heck of a lot of pages are missing because servicing was not included. Then he almost never see especially today is a watch companies don't like to share it typically today do not see the updates revisions or things you should be changed like for instance this comes from Omega document

Now some of these problems would rectify themselves in that if you purchased somehow a new part it would be the revised part. But on some of these revisions you're supposed to replace several parts so the only replaced one and did a mix-and-match that's not what you're supposed to be doing. But how would you know which is mostly doing because you don't have the revised technical document.

 

 

[pent]

Have you checked the sideshake/endshake of the barrel?  This will happen again if the root cause is the barrel shake.

[Nucejoe]

On 10/9/2023 at 9:39 PM, fellerts said:

 This wheel apparently has a slight bow to it and has obviously been rubbing on the barrel. I can also feel them binding if I assemble the barrel and the centre wheel and turn the barrel with some pegwood. 

If the wheel wobbles there is at least one bow. 

Flattening the wheel isn't actually that difficult, I do it in situ with a pair of tweezers.

Rgds

[fellerts]

8 hours ago, pent said:

Have you checked the sideshake/endshake of the barrel? 

Yes, it is ok as far as I can tell.

6 hours ago, Nucejoe said:

Flattening the wheel isn't actually that difficult, I do it in situ with a pair of tweezers.

I ended up flattening the wheel by placing it on a staking block such that only the rim of the wheel was supported and lightly pushing on the spokes immediately surrounding the pinion with a suitable stake. I can't discern any bow to the wheel, and it no longer touches the barrel.

Thanks for all your tips guys!