ETA 2472 Oscillating weight too much end-shake

[VWatchie]

The oscillating weight of the ETA 2472 that I’ve just serviced suffers from too much end-shake. I’d say minimum 0.02 mm to 0.2 mm (hard to say really). Anyway, the oscillating weight touches the setting lever screw when rotating. Not so much that it really hinders the oscillating weight from rotating, but enough to create a slight scratching sound. Very annoying! So, I filed down the head of the setting lever screw as much as I could (making sure to preserve just enough of the screw head slot). This was an improvement but didn’t solve the problem.

From ETAs technical communication for calibre 2472 about this:

"Adjust end-shake of oscillating weight.
If there is too little shake, increase it by removing material from cone inside tube, using a 60° milling cutter.
If there is too much shake, reduce it by removing material from cone inside spindle, using a 60° milling cutter.
Once adjusted, there should be about 0.02 mm end-shake at centre of oscillating weight."

I’m afraid I don’t understand the instruction because I don’t know what a "60° milling cutter" is (perhaps a tool for a milling machine?) and what ETA mean by "cone inside tube" and "cone inside spindle".

@anilv spontaneously, without me asking, wrote about this topic here (thanks!), but I’m not sure if I’d be able to get the mentioned parts and what tool would be required to "press fit the gear into the rotor". So, I’m bewildered and really don’t know how to proceed. I can only guess what things are, so I hope you can pair the terminology I don't understand with the included pictures to help me out on how to get on with this.
 

[Nucejoe]

What I asked in your prevous thread " eta 2472 auto device disassembly" may be the cause of rotor slack. Refer to post 375 in your previous thread.

A thin polymer washer may have been between the rotor screw and selfwinder module, very easy not to notice and loose it when disassembling. 

 

 

[rogart63]

Quote

 

Looks like the you should do the same ti increase or decrease the play . remove by using a 60 degree cutter inside the tube. Think they mean the tube on the rotor.  I think it's a drill or a cutter that has a 60 degree angle. Must be special tool for that?  I have only took an other screw when the rotor has been to loose. and it usually solves the problem. 

Edited October 2, 2019 by rogart63

[VWatchie]

4 hours ago, rogart63 said:

Looks like the you should do the same ti increase or decrease the play . remove by using a 60 degree cutter inside the tube. Think they mean the tube on the rotor.  I think it's a drill or a cutter that has a 60 degree angle. Must be special tool for that?  I have only took an other screw when the rotor has been to loose. and it usually solves the problem. 

Changing the screw and hoping it might solve the problem seems like the easiest thing to try. Stupid question but to make sure, do you mean the screw for the oscillating weight bearing (51498), the one seen in close-up in the second picture above?

[nickelsilver]

I think they mean something like a jeweler/dental burr to cut the tube a bit. We did the same on tubes to hold repeater components in production but just used round burrs. Normal burr angles are 90 and 70, there are 60 degree chamfering tools a bit larger (Eternal has them cheap). But really you just want the screw to get "tight" a bit lower. If it was me I'd just grab a round burr that hits kinda tangent on the 60 degree angle and go slowly. The tool needed to increase freedom seems way more complex. For that I'd chuck it on a faceplate but I have a dedicated setup for that and it'd take about 3 minutes plus possibly grinding a lathe tool and degluing time.

[rogart63]

1 hour ago, VWatchie said:

Changing the screw and hoping it might solve the problem seems like the easiest thing to try. Stupid question but to make sure, do you mean the screw for the oscillating weight bearing (51498), the one seen in close-up in the second picture above?

The screw that screws from the underside.  Haven't done super many 2472 but have done some . 1 or 2 i have changed the screw on. If it doesn't help i probably have some parts . Don't like this constuction but it looks tidy on the movement when the screw is hidden on the underside.

[nickelsilver]

Changing the screw 99% sure won't do anything. It's where the screw seats that matters.

[anilv]

For fitting the gear to the rotor, you don't really need a special tool, my staking set doesn't even have one so big!

You can punch it out from outer side (which faces the inside of the caseback) by using a suitable blunt punch. Even a wooden dowel works.. For installing you can also use a suitable wooden dowel but relieve the inside first to clear the pivot. Just go slow and constantly check to make sure it goes in straight.

Anilv

 

[VWatchie]

Thank you for your posts, very much appreciated!

I just realized there was an image (see above) of the 60° milling cutter tool suggested by ETA to adjust the oscillating weight end-shake in ETAs tech sheet for calibre 2472 (apologies, silly me!)

So, in both cases (too much/too little end-shake) what ETA tells us to do is to: “remove material from cone inside…”, either “tube” to increase end-shake, or “spindle (thrust point of screw)” to reduce end-shake. (I forgot to quote the “thrust point of screw” in my previous post, sorry!).

So, what’s the difference between a “tube” and a “spindle” and where are they located? Well, I can’t figure it out! Getting new parts from Cousins does unfortunately not seem to be an option as these parts are “Obsolete”.

Anyway, based on what I’ve read so far in this thread, the above is my guess of what I can try to do to reduce the end-shake. Let me know what you think (please verify!) I suppose it would be critical to get the cutter dead centre (90° angle) to the hole?

Edited October 3, 2019 by VWatchie

[watchweasol]

Hi After following this post and all the replys, It sounds like machining the bearing is the way but have you considered using a clock / watch broach and by hand removing material. I would think one or two turns would move enough material to suffice. The broach end the cutting end ground to the 60 deg angle.  Just a thought .

[Watchtime]

thanks for sharing, great info and detailed images...

[VWatchie]

The below picture is from ETA’s tech sheet for calibre 1256, and to me it looks like the oscillating weight of this calibre essentially is identical to that of calibre 2472.

ETA says: "To correct end-shake of oscillating weight, proceed as follows: to reduce end-shake, adjust inner cone of hub of bearing wheel 1498 (see arrow G on coloured plate opposite). To increase end-shake, adjust inner cone of tube of framework 1134 (see arrow H on coloured plate opposite). To fraise the cones, use a 60° conical fraise held in an ordinary chuck. When end-shake has been corrected, the 2 cones should be lubricated with good quality fine oil, and bearing wheel screw 51498 should be screwed home."

I’ve been unable to translate the word "fraise" from English to Swedish (my native language) but I believe it roughly means: ”mill”? Also, I don’t know what "an ordinary chuck" is, but searching ”chuck” on cousinsuk.com the below picture came up. Is that what ETA mean by ”ordinary chuck”?

If my questions seem unnecessary or stupid, please let me tell you that I’m basically a technical idiot whose most advanced tools in my adult life (I’m 60 in a few years) have been computer keyboards, mice, and touch screens and the like until recently. I must admit I'm having a hard time understanding all your pro terminology ("burr angles", "chamfering tools", "lathe tool", "faceplate" and so on...), and so I would find it extremely encouraging if you experts could confirm or oppose to the idea I show in the below picture. My idea seems very reasonable to my “digital brain” but having so little experience with the analogue world of watches I still feel very unsettled.

If you think my idea presented in the above picture makes sense to try, then what do think about the below tool that I found on Amazon.co.uk?

Sorry for being so wordy and thanks for your patience!

[watchweasol]

Hi   The object of the exercise is to decrease the shake, Then removing metal as suggested will do that. The medodology does not matter as long as it does the job. Reaming the tube to lower the weight will do as long as after every turn of the reamer you check the fit untlill you achieve the desired result. An ordinary chuck is like the one on a dremel to hold the bit. I would not use a power tool as the chance of removing too much metal is too high better to use hand tools for such an operation and take great care and check regularly.

[Nucejoe]

49 minutes ago, watchweasol said:

Hi   The object of the exercise is to decrease the shake, Then removing metal as suggested will do that. The medodology does not matter as long as it does the job. Reaming the tube to lower the weight will do as long as after every turn of the reamer you check the fit untlill you achieve the desired result. An ordinary chuck is like the one on a dremel to hold the bit. I would not use a power tool as the chance of removing too much metal is too high better to use hand tools for such an operation and take great care and check regularly.

Is this done free-handed?     

[rogart63]

It will probably self steer . A center drill like this is usually 60 degree. 

[watchweasol]

Hi  I would personally do it free hand as you have more control over the cut, Powertools will be a little too vicious, You could use an electric screw driver that runs on slow revs with a jacobs chuck. 

[VWatchie]

Thanks for your replies fellows, much appreciated! I will go with my plan and do it by hand. I will consider using a centre drill instead of the tool I linked to. Whatever my final choice of tool I'll let you know the results once I'm done.

Edited October 6, 2019 by VWatchie
Added some additional info

[VWatchie]

The results...

 

[VWatchie]

I forgot to mention that I'd very much appreciate your opinions if you have the time and interest to see the video. As always, the video could probably have been cut to a few minutes, but you can always speed it up.

[VWatchie]

Just a quick update. So, I replaced the bearing of the oscillating weight the way I demonstrate in my video. Somewhat to my surprise it didn't solve the end-shake problem. It was still too much. So, I used the my 60° milling cutter again (shown in the video) and this time around gradually, with a very light hand removed some metal from the tube inside the spindle (see arrow G in the illustration above). Be aware that it takes a very, very light hand! I assess that I removed just a few hundredths of a millimeter from the cone to get it just right/acceptable.

Still, the oscillating weight would (just barely) touch the outside of the setting lever screw. So, I replaced it with a screw which @rogart63so helpfully provided me (thank you very much!), but it still didn't solve the problem. So, I filed down the outside of the screw a bit and that finally did it. It bothers me that I wasn't able to find the true source of the problem, but at least the watch and the automatic winding now seem to work perfectly.

I've never spent this much time on any other watch before, and it was partly very frustrating, but also very instructive and I'm sure my newly acquired knowledge will be useful in one or another way in the future.

[watchweasol]

Hi well done watchie, patience is a virtue to quote a proverb .

[VWatchie]

Well, I have finally found the "true source of the problem", and I feel equally elated  and embarrassed 

The problem is that I replaced the setting lever screw after I replaced the barrel bridge, when in fact the setting lever screw must be replaced before the barrel bridge. Doing it in the wrong order "works" but it will make the oscillating weight slightly foul the head of the screw and it will make it impossible to remove the stem without the setting lever detaching from the setting lever screw.

This mistake I won't be doing again!