IWC Cal 52 broken staff pivot

Hello, I am new to watch repair and came across a problem I am hoping you guys that are more experienced can help. 

I have a nice pocket watch IWC Cal 52 serial #285624, and need to replace the balance wheel and the staff pivot. 

When I checked with the BalanceStaff.com, they have 2 separate model 52 pivots with different dimensions!

Can someone help me!!? I'm prepared to buy a movement for parts, but I'm not really sure if I'll have the right balance wheel and staff pivot!! 

Hello ELLEBAL.

I personally would go to the next IWC BTQ www.stores.iwc.com and ask for a service to be sure to get the right parts.

Hi Ellebal,

there is a Cal. 52 H5 and H6. The H stands for hight, H5 is 5.3mm and H6 is 6mm in height. That has of course an impact on the lenght of the balance staff. Just measure the height of the movement and you will find the tight part. Most probably you can also identify the Cal. 52 type from the movement number.

wish you good luck in finding the right part.

- Cromagnonman

According to the "Date your IWC" database, movement No 285624 is a Lépine c. 52 - 19lig H7. 

As Cromagnonman said, you will have to measure the height of the movement in order to verify. 

Thank you guys/ Crowmagnonman!! I see that a 52H7 is required!! I can't figure out where I got the H6 from!! 

Thank you Ben! It is a 52H7... 

I'm trying to find the dimension specs of the IWC 52 H7 pivot/staff, I can find 52H5 and 52H6, but nothing on the H7!! 

Also, the height of the movement (or thickness) is 7mm, is this where they get the H7? 

Sorry if my questions are seemingly idiotic, I'm a beginner trying to save this beautiful piece of intricate mechanics!! 

My Catalogue of spare parts no. 7

Has the following information for H5, H6 and H6 1/2. 
Perhaps H6 1/2 equates to H7?

The H number should be engraved on the movement somewhere or close to the balance, as shown in the illustrations above. Or you will need to measure the movement Height as Ben and Cromagnonman suggested. 

H5 - 4378 = FH 723

H6 - 4278. = FH 723

H6 1/2 - 4178 = FH 723 
FH = Swiss Federation of Watch Manufacturers' Associations

So that doesn’t help much. 

Restoring a vintage IWC Cal 52 pocket watch is a rewarding but tricky task, especially when it comes to balance staff replacement. Since BalanceStaff.com lists two different pivots for this model, the safest approach is:

Steps to Ensure Compatibility:

1. Measure Your Current Staff Pivot – If you have the old balance staff (even if broken), use a caliper or micrometer to measure its exact dimensions. Compare this to the specs listed on BalanceStaff.com.
2. Check the Serial Number Range – Sometimes, manufacturers made minor modifications over time, even within the same caliber. If possible, cross-check with an IWC parts guide or forum to confirm the correct part for your serial #285624.
3. Consider a Complete Balance Assembly – If you’re unsure, buying a complete balance wheel + staff assembly from a donor movement might be the easiest route. This avoids compatibility issues with pivots alone.
4. Ask a Professional – If you don’t have the right measuring tools, visiting a watchmaker for an inspection can save you time and money before buying the wrong part.

Bonus Tip

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