Jump to content

How to replace a Novodiac spring without a tool?


Recommended Posts

I've seen some genuine ETA 6497-1's that use Novodiac type springs instead of a standard Incabloc. There are special tools made for Novodiac springs for various ETA movements but there is no such a tool available for 6497.

So, I would like to know how difficult would it be to handle the replacement in absence of the tool?

How do you push it down simultaneously in 3 places so it can be rotated to enter under the lips?

What technique brings best results?

Link to comment
Share on other sites

It is possible to remove the Novodiac with a toothpick that has the point cut off, You oce the blunt end over the spring and apply slight pressure downward while turning. ...but you may have trouble replacing it with that technique because you won't be able to see it when it locks in place.  I wasn't able to do it without  damaging it. I would suggest you save yourself the grief and buy  KIF or Novodiac tool. I bought mine from J Borel when you could buy a single tool (they come on three sizes) but now you have to get the set.

KIF tools_J Borel

NOvodiac_KIF tools_O_FREI

Joe

  • Like 1
Link to comment
Share on other sites

OFrei and Borel both offer tools for Novodiac springs, and a set of these comes with 3 sizes. Neither of the sizes list 6487 as a caliber that would specifically fit any of the tools from the set.

It would be great to know whether someone used one of these tools, presumably the largest size, successfully on 6497/6498.

Link to comment
Share on other sites

Clarifying: 

OFrei and Borel both offer tool sets for Kif Trior springs, and a set of these comes with 3 sizes. The first question for me would be whether these tools for Kif Trior would work OK with Novodiac springs, since the springs are not exactly the same. If the answer is yes this would probably solve this problem. Also, Horotec makes a couple of tools specifically for Novodiac springs, and specifically for some ETA calibers (2801, 2824, 2834, 2836, 2660, 2671, and 2688). Neither one list 6487 as a caliber that would fit any of these tools.

It would be great to know whether someone used any of these tools successfully on 6497/6498 Novodiac spring.

Link to comment
Share on other sites



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • That's a good idea - shrinking down the nut and wrench size from the old casebook trick!
    • I missed this earlier. The dial isn't going into the holder, it should sit proud of it. This is what I am currently using which I print for each different movement.    
    • I didn't think pulling to set position would work harden the spring, in that position it is stressed where the arm starts. By work hardening i meant rapid polishing at that point, a bit like polishing a pivot work hardens as it compresses the steel. I doubt polishing by hand would achieve much in that respect though. Its finished, arm polished up mostly at the join to the bridge's main body. I'm ok with it, the screw holes aren't great as i had to open them up by redrilling and positioning it was difficult, I'm not much use with a loupe, opening up with a file might be a better option for me or i could just use the correct drill size 😅. And the detent is way too deep, i had to guess that with the stem release out of position and sat on top, but i only took one measure and went for it, no slowly slowly catch your monkey 😅. First go I'm happy , well sort of, it works and thats a big thing for me, next one will have a bit more finesse.  Anyone thats interested, after filing, i used a 2000 grade home made diamond  micro file and then 20 micron film, the film is much better than wet and dry, more stable to use and doesn't shed cheap grade grit everywhere , then auto polish on a sponge pad.
    • I'm assuming that every time you set the watch you are work hardening the detent spring, maximum hardening is  where it meets the plate due to maximum deflection.   That's why it snaps there.  The Young's modulus may be the same but after it's reached its maximum yeid strength it breaks.  My mechanic engineering is very rusty, correct me if I'm wrong. 
    • Ah ok yes that makes sense to polish it where the arm starts to form from the body of the bridge, i thought you meant the underneath of all the arm.
×
×
  • Create New...