Jump to content

Mainspring arbour won't catch

p2n

By p2n
in Watch Repairs Help & Advice

 Share

Recommended Posts

p2n WRT Addict

p2n

Posted
Posted

Been trying to fit the mains spring on my Elgin B&B. I broke the last one.

I've hand fitted the spring but the arbour won't catch. A close look shows this seems to be because the hole in the end of the spring is further back on the new spring than the old one.

All these photos are the same scale. The red lines indicate the problem measurement - the old spring and the arbour match, but the new spring is bigger.

I can't change the new spring so is it acceptable to file the arbour to make that space a little longer?

mainspring.jpg.b142d032b1743569da913679a2f8fa7d.jpg

Link to comment
Share on other sites
rogart63 Distinguished Member

rogart63

Posted
Posted (edited)

Should work i imagine. But what to do if it doesn't work? Can you find a new arbor? That is how i usually think when i  modify parts? Can i find a new or used parts i go ahead and learn something on the way. 

Edited by rogart63
Link to comment
Share on other sites
p2n WRT Addict

p2n

Posted
  • Author
Posted

I did think of that but I've still not found a good source of parts for these old pocket watches - I've only been watch bothering for 3 months.

I'm guessing there was no such thing as standardized sizes back then?

Link to comment
Share on other sites
rogart63 Distinguished Member

rogart63

Posted
Posted

Could you remove some from the end of the mainspring. If you could reach down there with a file without damage anything else? A thick paper behind and file enough material to get the mainspring down in the groove. Can show you tomorrow what i mean. 

Link to comment
Share on other sites
praezis Super WRT Addict

praezis

Posted
Posted
52 minutes ago, clockboy said:

It's just the basics of horology you always just adjust/repair the faulty part. By altering the arbour (if it works) it will only work with that specific spring. 

Thank you! It is important nowadays to repeat this basic rule now and then.

Frank

Link to comment
Share on other sites
p2n WRT Addict

p2n

Posted
  • Author
Posted
12 hours ago, rogart63 said:

Can show you tomorrow what i mean. 

Any tips would be welcome. My needle file seems huge compared to the size of the spring.

Link to comment
Share on other sites
Tmuir Distinguished Member

Tmuir

Posted
Posted

You may have trouble filing it with a regular file being the spring will be hardened. Have a look at getting yourself a small diamond file. I've bought a couple and really do love them, but like most things the more you spend the better it will be. The $2 diamond files aren't really worth the time

Link to comment
Share on other sites
rodabod Distinguished Member

rodabod

Posted
Posted

Mainsprings are not fully hardened at the end; they are annealed. That’s why you can easily modify their profile to match the curve of the arbor easily. Either file or punch it. If you file it, make sure your file has suitable safe-edges, and modify the file if need be. 

Link to comment
Share on other sites
 Share
Go to topic listing


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • Endeavor
      New balance staff not riveting to balance

      By Endeavor · Posted

      The whole process and the progress are closely observed, it's hand-driven and very controlled. I can't see the "danger", unless you are watching the TV while doing it. As you could have read, and in this quote "wheel" is the balance-wheel.
    • Mercurial
      AS2063 - hand setting

      By Mercurial · Posted

      Have you got the pallet fork installed in the movement when you see the train move when using the setting works? As nevenbekriev said, without the pallet fork to lock the train, the behaviour you are describing is normal. If this is happening with the pallet fork installed, you have a problem in the gear train, it should be immobile when the pallet fork is locking the escape wheel.  The fit of the circlip above the pinions on that wheel is crooked in your pictures, it should sit flat up against the upper pinion as in Marc’s picture.  Hope that helps, Mark
    • Khan
      Stem broken - can it be rescued?

      By Khan · Posted

      Hi I got a Jaeger LeCoultre K911 movement, where one of the stems was broken. Part no. Should be 401.  Im based in Europe and tried Cousins but its discontinued. They except to get stem in stock for cal. K916 but will that work? Or Is there a way out to join the ends?
    • Bonefixer
      AS2063 - hand setting

      By Bonefixer · Posted

      The part was how it fell out of the movement - the train wheel bridge wasn’t screwed in.    I’ll probably dismantle the part, if I can, to work it out.    The train of wheels ran fine - it was only once the keyless works were installed I noticed the problem. 
    • mthomas828
      Balance staff sourcing?

      By mthomas828 · Posted

      Hello, I am about 5 months into watchmaking and I love it!   The attention to precise detail is what really attracts me to it. (and the tools!) I am working on a 16 jewel 43mm pocket watch movement.   There are no markings besides a serial number (122248) .  The balance staff needs replacement. The roller side pivot broke off.  I successfully removed the hairspring using Bergeon 5430's.  I successfully removed the roller using Bergeon 2810.   Did i mention I love the tools?! I removed the staff from the balance wheel using a vintage K&D staff removal tool  with my Bergeon 15285 (that's the one that comes with a micrometer adjustment so it can be used as a jewel press as well as a traditional staking tool...it's sooooo cool...sorry..  can you tell i love the tools?) No more digressing..  I measured the damaged staff in all the relevant areas but I have to estimate on some because one of the pivots is missing. A = Full length  A= 4.80mm  (that's without the one pivot...if you assume that the missing pivot is the same length as the other pivot (I'm sure it's not)  then A = 5.12 mm...(can I assume 5.00mm here?) F=  Hair spring collet seat  F=  .89mm   (safe to assume .90 here? .. I am sure that my measurement's would at least contain  .01 mm error ?) G = balance wheel seat  G = 1.23 mm  (1.20mm?) H  =  roller staff  H =  .59mm  (.60 mm?) B  = bottom of the wheel to roller pivot   B  = 2.97mm  (3.00 mm?)     here I am estimating  again because this pivot is missing. So my friends, and I thank you profusely,  can you point me in the right direction as to how to proceed? Do i buy individual staffs?  or an assortment?   Since I don't know exactly the name of the manufacturer, will that be a fatal hindrance?   Tbh, I'm not even sure what country of origin this movement is. Thank you!    
×
×
  • Create New...