Is it possible to repivot a seiko 6139 chrono wheel?

[Fred]

Hi WRT,

I have a 6139 chronograph with a broken chrono wheel. Is it possible to repivot it by turning a piece of blue steel and drilling a hole for a friction fit?

Thank you

[rogart63]

Never seen that done? It's a pretty small pivot. Which side is broken? Is it where the chronograph hand is? 

[jdm]

Check http://www.speedtimerkollektion.com/shop/product_info.php?products_id=25462

Or search the part you need on the same site.

[rogart63]

25 minutes ago, jdm said:

Check http://www.speedtimerkollektion.com/shop/product_info.php?products_id=25462

Or search the part you need on the same site.

The chronograph wheels are superhard to find. I don't think speedtimer has one. if they would i would have seen it first

If it's an 6139A it could be easier? 6139B chronograph wheels are rare. 

[Fred]

1 hour ago, rogart63 said:

Never seen that done? It's a pretty small pivot. Which side is broken? Is it where the chronograph hand is? 

Yes, it's where the hand fits. Ill attach a picture. Is it better to cut it down to the pinion and then drill it and turn a pivot and friction fit it?

[praezis]

17 hours ago, rogart63 said:

Never seen that done? 

Drilling and replacing the pivot should be the preferred method IMHO if parts are rare. Rather than changing the whole wheel, this will save scarce resources. Chronograph runners are the first parts that get unavailable, guess why?
For skilled and well equipped workers this repair is fast and not very difficult to do. Last year I got a WW2 chronograph in my workshop for repair. Both chronograph runner and minute register wheel had their pivots broken and sapphire jewels cracked.
Tools used: Lathe, center drill 0.20mm, drill 0.25mm (both tungsten), Pivofix or Jacot tool: 

Frank
 
 

[praezis]

I would not do this on the hands side. Removing the hand, you will pull the new pivot out of the staff. But a staff can be turned, it is similar to turning a balance staff, but the long thin pivot will be tricky.

Frank

[jdm]

1 hour ago, praezis said:

I would not do this on the hands side. Removing the hand, you will pull the new pivot out of the staff.

Would it help turning with a  bigger diameter where fitted on the existing shaft, so more friction there.

[Fred]

6 hours ago, praezis said:

Drilling and replacing the pivot should be the preferred method IMHO if parts are rare. Rather than changing the whole wheel, this will save scarce resources. Chronograph runners are the first parts that get unavailable, guess why?
For skilled and well equipped workers this repair is fast and not very difficult to do. Last year I got a WW2 chronograph in my workshop for repair. Both chronograph runner and minute register wheel had their pivots broken and sapphire jewels cracked.
Tools used: Lathe, center drill 0.20mm, drill 0.25mm (both tungsten), Pivofix or Jacot tool: 

Frank
 
 

Hi, thanks for the walkthrough, the problem is I dont know how to hold the wheel, I dont want to break those springs.

[praezis]

19 hours ago, jdm said:

Would it help turning with a  bigger diameter where fitted on the existing shaft, so more friction there.

Usually there is a brass bushing in the.center bore where the long pivot must pass. A thicker plug will prevent this.

Frank