Jump to content

Broken Stem Inside Crown...


DJW

Recommended Posts

A new Miyota 2035 movement  complete with stem is only around £3.50.

Cut to the right length and fit a new crown. A lot easier than drilling the crown.

You will need a new stem anyway because the old one will be too short.

Chris

Link to comment
Share on other sites

If you wish to re use the crown (though an appropriate replacement shouldn't be too hard to source just looking at the picture) you can corrode out the steel of the stem over the course of ~a week using a solution of water and aluminium potassium sulphate (easily found online, it's used to whiten bread), this rarely if ever effects the crown itself as it is made up of different metals or stainless steel, not regular steel. 

Edited by Ishima
Link to comment
Share on other sites

  • 4 months later...

Hi guys,

 

The stem on this watch was bent close to the crown, and snapped off, leaving a tiny piece inside the crown. The piece is too small to get hold of with a tool.

 

11dca743902cb9e25dd8753f5907ec3d.jpg

 

Is it an option to use Alum to dissolve the system piece, or would that damage the crown in the process? Do you have other suggestions for getting the broken stem out?

 

Thanks,

Stian

 

Sent from my VIE-L09 using Tapatalk

 

 

Link to comment
Share on other sites

7 hours ago, Stian said:


Thanks, did that in any way damage the crown?

Stian

Sent from my VIE-L09 using Tapatalk
 

No, but I hesitate to say you'll have the same result.

The alum water solution will react with carbon steel (the stem) but the thing to remember is if there is any carbon steel in the crown then it's at risk as well.  Most crowns seem to be either plated brass or stainless steel and alum doesn't seem to be very reactive with those metals.

  • Like 1
Link to comment
Share on other sites

Thanks, guys. This is an original crown for a vintage watch, so replacing it is really the last option.


Vintage of a value such to require full original parts? You will be surprised at the variety of a good crown assortment.
Link to comment
Share on other sites

A new crown would be my option. If not then drill it out but be warned it could damage the thread of the crown if not careful.


Thanks, and what is the best way to drill the old screw out then?

Stian

Sent from my VIE-L09 using Tapatalk

Link to comment
Share on other sites

54 minutes ago, Stian said:


Thanks, and what is the best way to drill the old screw out then?

Stian

Sent from my VIE-L09 using Tapatalk
 

In a lathe? with a small drill then larger and larger until you can remove the threads? But not sure it will work? 

For what  watch  is it? 

Link to comment
Share on other sites

In a lathe? with a small drill then larger and larger until you can remove the threads? But not sure it will work? 

For what  watch  is it? 


It's for a Zenith 133.8

Sent from my VIE-L09 using Tapatalk

Link to comment
Share on other sites

There is crowns for Zenith on Cousinsuk if it doesn't work. But i guess they are only for the newer Zenith? 


Yeah, and fit vintage watches it's really important for the value to keep it original as far as possible... But thanks anyway :)

Stian

Sent from my VIE-L09 using Tapatalk

  • Like 1
Link to comment
Share on other sites

"how would I grab the stem - stub"  that is the chalage.  first get penetrating oil down alongthe threads.  (I prefure it to allum).   NOW to turn out  the stub.  one way is to use a left hand turning drill.  first try  moving it with a very small punch.  BUT most would just buy a new one (save the original).  vinn

Link to comment
Share on other sites

Stian, it's likely that the stem is done up tightly or possibly even loctited in place. If the latter then this will be a challenge to deal with. You can try alum, but any plain steel parts will be attacked too.

Loctite threadlockers for this kind of application should be low strength, but you have nothing to hold on to, so that won't help much. The strength is dramatically reduced by heating to about 250C, but if you have a rubber seal in there, you don't really want to exceed that for long. Sometimes the washer can be prised off so you can remove the seal and then heat without fear. If it's a regular o-ring then that means you can also fit a new seal afterwards.

The stem is hardened and therefore will be difficult to drill, but not impossible.  Because the stem is hard, if it has broken with a ragged edge, that will make drilling it centrally more tricky. The upside is that this means you may be able to use a screwdriver to turn it - hold it in a pin vice whilst still hot.

If the surface is completely flat, you are going to have to drill it, and as others have said a lathe gives you the best chance of centring things. I would heat it for an hour or so first to help break down any loctite present.  What you are trying to do is to drill out to the thread root diameter (of the stem, not the crown!) and then you should be able to chase the remainder out with a tap or fine needle. If you end up drilling off centre then just make sure your drill is small enough to stay inside the thread root and not damage the thread in the crown.

 

 

Link to comment
Share on other sites

I had a stem broken flush in a signed vintage Camy crown , so replacement wasn't really an option .

I got some alum powder cheap from Ebay and gave it a go , I have to say if i hadn't seen it with my own eyes i would of doubted it at best ,or never believed it at worst. In approx 24hrs the old stem had completely dissolved away.

Maybe i was just lucky but it worked for me , I did make a strong solution and read that it worked best warm so warmed it up also, if it's working you will see bubbles coming from the stem.

Good luck

Link to comment
Share on other sites




  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • To me this is a simple solution but not just for UK. I know a lot of us are not into facebook groups. But Mark has one, so does Mike Bolton of my retro watches, so does Kalle Slapp. They cost nothing to run, my daughter runs a few dog groups with thousands of members. And it does not have to be actively used, just because you are not interested in facebook ( i wasn't for a very long time ) that doesn't mean you have to participate on it or read anything posted , that is anyone's choice to do so, you give or take what you want from it. Seems the ideal meet place to me, join it , make one or two posts just to say " I'm here " then set it aside for a rainy day. If or when that day comes then discussions can take place as what to do next.
    • Hi Bob, Welcome to the forum and thank you for your service.  I would never try to discourage you from getting into this wonderful hobby/profession, but please be aware, it does not cost just a few dollars to get into watch repair.  Tools are expensive and in many instances the cheap knockoffs are worthless, especially when learning.  You can get the tools needed to disassemble, clean, inspect, reassemble and lubricate a watch without spending thousands, but as soon as you start getting into task-specific tools, there are so many and they don’t come cheap.  My suggestion is to start with the basics required to disassemble, clean, inspect, reassemble and lubricate only, and build upon that gradually as the need for other tools arises.  The advice above regarding starting out on working movements is gold. Many of the non-running watches on eBay have been bought, tinkered with, deemed too difficult and then sold again, often with more damage done each time.  Without experience, you clean and service a non-runner and it still doesn’t run. What now? Troubleshooting is difficult as a beginner. This can become very frustrating.  I would encourage you to buy a working movement, and learn to strip and service it. If it isn’t running afterwards, you know it’s down to you, and as long as you didn’t damage anything you know that the parts you’ve got can form a ticking watch. An excellent movement to start with is the ETA 6497 clones from China, such as the ST36. They’re not expensive, and although it finds use in some larger wristwatches, this movement was originally designed for use in pocket watches, so everything is larger and easier to see and handle.  Once you can service a new ST36 and have it running better than it did when it arrived, you’re definitely ready to step up to working vintage watches and then think about repair of non running or poorly running watches.  As far as cleaning solutions go, you will not do better than the commercial watch cleaning and rinsing solutions that are available. You’ll find plenty of suggestions for home brew cleaners online, but the professional products are superior and you want to give yourself every advantage you can, especially when you start working on vintage movements containing hardened decomposed lubricants and often years worth of other dirt and dust. Alcohol is ok for cleaning or rinsing movement parts that don’t contain any shellac. The pallet fork and roller table contain jewels secured with shellac and will tolerate a rinse in alcohol but not prolonged exposure. Methanol dissolves shellac faster than ethanol, and isopropyl alcohol dissolves shellac slower than ethanol. Just in case you don’t know already, the radium on the dial (and likely the hands) of your Dad’s Elgin is highly radioactive. It is safe enough when safely contained within the watch case, but the moment you open the watch and especially when handling the dial or hands you must take precautions against inhaling or ingesting any radium.  Best Regards, Mark
    • I have both sets and use the K&D 99% of the time.  Yes, you have to be careful with the pin.  I use a screwdriver to carefully release the pin from the spring.  Some skill is involved.   I have also modified/replaced the pins in the arbors as necessary.  Yeah, you would think a tool would not require modification, but such is the world of watchmaking.  There is no perfect tool.  Each watchmaker must the tools to his skill, or vice versa.
    • I have the 8-11mm K&D but it doesn't do a great job with modern mainsprings, or I have had terrible luck. The arbor pin protrudes too much and I have damaged more springs trying to disengage the arbor than I have successfully wound and inserted. It seems easier to use with old carbon steel springs. My Watchctaft set gets far more use, though I have to get creative to wind left hand springs
    • It depends on what the gaskets are made from but silicone lubricant should work.  Spray or rub on a generous amount, put in a sealed bag and wait a couple of days.  Test for softness and wipe off the excess.  
×
×
  • Create New...