Jump to content

Bent forth wheel pivot - what do you do?

Stian

By Stian
in Watch Repairs Help & Advice

 Share

Recommended Posts

Stian WRT Addict

Stian

Posted
Posted

Hi guys, 

I working on a watch with small seconds, and the extended pivot on the fourth wheel is a bit bent. I would assess it to be maybe 3 or 4 degrees bent. This is enough for the seconds hand to rotate on a tilted plane, and the dial had been marked by it. 

Do you try to straighten the pivot, and if so, how? 

--

Thanks, 

Stian 

Link to comment
Share on other sites
Stian WRT Addict

Stian

Posted
  • Author
Posted

Hi Stuart, 

Thanks, I should have specified that this is a vintage watch and finding a new arbor would be very difficult. 

Would you have any guidance on when you would expect it to break and when you would think you can straighten it? E.g would it depend on the angle, the method etc? 

Stian 

Link to comment
Share on other sites
StuartBaker104 Distinguished Member

StuartBaker104

Posted
Posted

Hi Stian,

It is more likely to break if you can't find a replacement :-)

On older watches, the hardness of these parts is somewhat unpredictable. Seitz makes a special tool for straightening pivots, but they are expensive even second hand.  This would give you more control, but wouldn't help with certainty.

If it is only a few degrees you may get away with it. Do you have a staking set with hollow punches?

If you post some pictures we may be able to help identify the movement. Key features are usually the keyless works parts and the diameter, but also good to see the bridges and any markings

 

Link to comment
Share on other sites
jdrichard Distinguished Member

jdrichard

Posted
Posted

I had the same problem and was successful in straightening it out. I used a pair of pliers and carefully worked it. Then I used my Jacot tool to smooth out any scratches I made with the pliers. As mentioned by others, the pivot could break if you are not careful and even if you are. However, you really have no choice other than getting a new wheel and shaft.

Sent from my GT-N5110 using Tapatalk

Link to comment
Share on other sites
matabog Super WRT Addict

matabog

Posted
Posted

Never done it myself, but from what I heard, if you want to work with the pivot (in any way) you must first soften the material (meaning turning it red, letting it cool down) and then hardening it again.

Good luck with that!

 

 

Link to comment
Share on other sites
praezis Super WRT Addict

praezis

Posted
Posted

@ matabog: Oh god, do not heat to red! Light blue is sufficient.

If it is bent 3-4 deg only, danger of breaking is not so high. I do this very often, repairing chronographs. I use to hold the pivot (the straight part) in a lathe collet, turn the spindle and compare the other pivot to the tip of the headstock. Bend the pivot with light taps until the wheel wobbles no more.

Frank

 

 

 

Link to comment
Share on other sites
anilv Distinguished Member

anilv

Posted
Posted

General answer.

1st step (hardening). Heat red hot and quench in oil.

2nd step (tempering). Heat but not red hot. straw is the usually quoted  colour , then quench again.

The problem is these processes work on larger items where the piece heats up gradually. A small part like a pivot will heat up red-hot practically instantly. You would need to set up a bed of copper shavings and heat this part on it but it pretty hit and miss. There are some good videos on hardening watch parts on youtube.

A replacement would be the way to go.

Anilv

 

Link to comment
Share on other sites
StuartBaker104 Distinguished Member

StuartBaker104

Posted
Posted

I came across this thread whilst researching re-pivoting earlier. http://mb.nawcc.org/showthread.php?118580-Escape-wheel-pivot-repair

The idea of letting down the temper slightly might appeal. I'm no expert in this, but suspect that re-tempering the whole pinion with wheel attached is going to cause you bigger issues than you have already.

Link to comment
Share on other sites
praezis Super WRT Addict

praezis

Posted
Posted
 

I came across this thread whilst researching re-pivoting earlier. http://mb.nawcc.org/showthread.php?118580-Escape-wheel-pivot-repair

The idea of letting down the temper slightly might appeal. I'm no expert in this, but suspect that re-tempering the whole pinion with wheel attached is going to cause you bigger issues than you have already.

You are right. I do not heat at all, but reducing the temper to blue or light blue may help. Tempering again is not needed.

Frank

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


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • ManSkirtBrew
      1972 Bulova President "E" Sea King 11ACACB movement

      By ManSkirtBrew · Posted

      Oh nice. I have a similar wedge style stump for my staking tool, so I'll give that a shot. Thanks!
    • joelcarvajal
      Gamblin Gamsol for cleaning?

      By joelcarvajal · Posted

      Thank you all for the replies!  Very informative! True enough, the Gamsol took some time to evaporate and does leave a residue. So not all naphtha are created equal!  Need to find alternatives then. i was able to try Hexane recommended by Alex and it seems great.  I wonder what the cons are?
    • GuyMontag
      1972 Bulova President "E" Sea King 11ACACB movement

      By GuyMontag · Posted

      Yeah, I saw that in the tech sheet but I don't see how it can be adequately cleaned with the friction pinion still in place. I've accidentally pulled the arbor right out of the wheel once when I used a presto tool to try and remove it. Mark shows how he does it with the Platax tool. Those are a little too pricey for me so I got one of these from Aliexpress and I just push down on the arbor with the end of my brass tweezers. That usually gets it most of the way out and then I just grab the wheel with one hand the and the friction pinion with the other and gently rotate them until it pops off. Probably not the best way but it's seemed to work for me so far.    
    • Zedster
      Movement inserted from crytal side

      By Zedster · Posted

      Thanks, Jon Sounds like a plan. Obviously I'll have the face on so do you think gripping with the holder will create any problems, but I will check in the morning to see how feasible it is but I assume it only needs to be lightly held. As for holding the movement instead of the holder won't be possible in this scenario as one hand will be puling on the stem while the other pushes the spring down. That was my initial concern is how the hell can I do this with only one pair of hands. All the other times I've had to remove the stem hasn't been a problem, apart from the force required to release the stem from the setting lever, but now I need to fit the face and hands its sent me into panic mode. If it had the screw type release things would be a lot simpler but that's life 😀   Another thing I will need to consider is once the dial and hands are fitted and the movement is sitting in the case I will need to turn it over to put the case screws in. I saw a vid on Wristwatch revival where he lightly fitted the crystal and bezel so he could turn it over, is this the only option or is there another method?      
    • nevenbekriev
      Main spring

      By nevenbekriev · Posted

      Hi Jon, do You think that relation spring torque - amplitude is linear? I would rather guess that the amplitude should be proportional to the square of the torque. I had once idea to check it, but still haven't.
×
×
  • Create New...