Jump to content

ETA 2472 Oscillating weight too much end-shake


Recommended Posts

y4mDP7LoJJYi_U4ntXqkYM--J8tGWeasywndSnK5

y4muomTYHSFyO6rpazAAQ3ID-oAXpGGOtejfU5hU

y4mA5K3AsVEQxXbo1A0VaDXAgKlmfcDQ3FyXH_nV

y4m0KOeN3Bj0UlWimLc2LUxhPiBjhGv1ik_3tfVP

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.
 

Link to comment
Share on other sites

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. 

 

 

  • Like 1
Link to comment
Share on other sites

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 by rogart63
  • Like 1
Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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.

  • Like 1
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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

 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Thank you for your posts, very much appreciated!

y4m56MwhwNUaCHjCblXcMqyubo8oU_oK-NjIdsuy

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”.

image.thumb.png.2b2d6d4ac74f7ca9e93e5838bff6de60.png

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 by VWatchie
  • Like 1
Link to comment
Share on other sites

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 .

Link to comment
Share on other sites

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.

image.thumb.png.4d0824c02bba99ad14fd7e65825a65fe.png

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”?

image.png.b1f4e7e420d5460d39e3ed700e1ce25c.png

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.

image.thumb.png.fa0e0d4efe7ee5690ba1a0f5cca4c391.png

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?

image.png.6f01d71eea9d7c7da66abe173bc56c4d.png

Sorry for being so wordy and thanks for your patience!

Link to comment
Share on other sites

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.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

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?     

Link to comment
Share on other sites

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 by VWatchie
Added some additional info
Link to comment
Share on other sites

  • 2 weeks later...
  • 2 weeks later...

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.

Link to comment
Share on other sites

  • 2 weeks later...

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!

 

Link to comment
Share on other sites



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • What is seen on the first video (by the hairspring breathing) is that the amplitude is really high. The other thing seen is that when expands, the hairspring probably touches the stud. So, what You can do is center the hairspring better as it will stay a little away from the stud. Then, check You amplitude. One way to do it is to put a dot with marker on the balance rim and observe it's movement. The other way is to check if the lift angle for the movement is different from the magical number 52 and insert the correct number in the timegrapher. And if really rebanking happens, then You can return the old spring and check what will happen then. Yes, You can close a little the regulator pin. But it will not solve the problem.
    • I have to double check the lid.  I do remember seeing an index mark on some part of it last night that I didn't expect to see one.  I don't remember if it was the lid or not.  Why would they have created them where orientation is necessary?  Or was it a limitation of the fabrication technology available at the time? Will do.  Thank you.  Though I should mention that the barrel did not have the mainspring in it when I took the picture.
    • I was able to move the problem to the DU position by changing the height of the stud pin in the balance bridge. 😵‍💫  Initially, I had the stud pin in as far as it would go (I had removed the balance wheel from the cock to clean the pivots).  I loosened the stud screw and let it find the position that it wanted to and tightened it back up.  The craziness moved to DU.  Fiddled with stud position, to get the mainspring to lay flat, but that brought the problem back to DD. I'm not sure what you call this type of regulating pin arrangement.  You need a screwdriver to rotate the one side to release the hairspring.  There's a little ledge that sticks out from that rotating piece and the hairspring could be rubbing on that. It does look like the regulating pin gap needs to be minimized.   I measured the old mainspring at 1.6mm x 0.11mm x 9mm and that is what I ordered.  Got it from Cousins, GR4514. Emmy Watch does list mainsprings with slightly different specs. https://www.emmywatch.com/db/movement/benrus--ba/   There does seem to be a bit much gap between the regulator pins.  I will try to adjust that.   Yes, fully wound.  Though, I let it run overnight and checked it this morning and it was still acting bizarrely. It can be intermittent.  The timegraph can look more normal, then start going awry.  Once awry, though, I haven't seen it go back to normalcy unless I change the position and then go back to DD.  That is not always the case, though.
    • Well, in the fusee barrels You shouldn't put the lid in wrong position as the hole in the barrel where the chain hook goes must be exactly against the cut place in the lid. If not, the chain hook may not get in place. OP, What You should do is to remove the spring from the barrel and assemble it exactly as it looks  in the photos. Then grasp the arbor with something and rotate the barrel. This will show if the barrel is not true or the arbor itself is not true. If the barrel rotates true, then the arbor is the reason for the tilting. If the barrel doesn't rotate true, and this is so much that rectifying is needed, then the best option is to make new lid that will compensate for the barrel being not true. If this is to be done, I will give further instructions what to do.
×
×
  • Create New...