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Balance staff: is this a decent quality?

Kalanag
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Kalanag Super WRT Addict

Kalanag

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I‘m going to replace the balance staff of a Russian pocket watch (Molnia 3602). Because it is the first time I purchase a balance staff as a spare part I am not sure about the finishing quality to be expected. Here are some pictures from what I got (ebay, „NOS“). Is this a decent quality for such an item or is it chunk? Your educated comments are highly appreciated.

IMG_8382.jpeg.d4c511f608ce17f8767d40b7de3fabdb.jpeg

IMG_8378.jpeg.0b5ffe5d375e9f2544671e99abfa8d95.jpeg

 

Edited by Kalanag
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  • Kalanag changed the title to Balance staff: is this a decent quality?
Neverenoughwatches Distinguished Member

Neverenoughwatches

Posted
Posted
2 hours ago, Kalanag said:

I‘m going to replace the balance staff of a Russian pocket watch (Molnia 3602). Because it is the first time I purchase a balance staff as a spare part I am not sure about the finishing quality to be expected. Here are some pictures from what I got (ebay, „NOS“). Is this a decent quality for such an item or is it chunk? Your educated comments are highly appreciated.

IMG_8382.jpeg.d4c511f608ce17f8767d40b7de3fabdb.jpeg

IMG_8378.jpeg.0b5ffe5d375e9f2544671e99abfa8d95.jpeg

 

The hub looks a bit rough and the pivot doesn't seem particularly polished but that might just be because the photographer seems to have taken the picture with a potato 🥔.  😉 . The rivet still looks like it has its shape though.

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Kalanag Super WRT Addict

Kalanag

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On 12/16/2023 at 5:02 PM, CYCLOPS said:

you should be able to use after clean-up in lathe as long as the hub fits the balance wheel.....

Meanwhile I found some time to investigate the dimensions of the new staff.

- The pivots fit the jewel holes

- The end shake is fine

- The wheel hub fits the wheel diameter

BUT

- The double roller ID is 0,2mm smaller than the staff‘s OD (0,4 vs. 0,6mm) 🤨

Not having a lathe, what would you folks do?

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Neverenoughwatches Distinguished Member

Neverenoughwatches

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Posted
10 minutes ago, Kalanag said:

Meanwhile I found some time to investigate the dimensions of the new staff.

- The pivots fit the jewel holes

- The end shake is fine

- The wheel hub fits the wheel diameter

BUT

- The double roller ID is 0,2mm smaller than the staff‘s OD (0,4 vs. 0,6mm) 🤨

Not having a lathe, what would you folks do?

Jacot ?

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Neverenoughwatches Distinguished Member

Neverenoughwatches

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5 hours ago, Kalanag said:

I should have mentioned that I don‘t have a Jacot tool.

Ronda catalog is showing the roller table diameter on staff as 56 maybe roller is too small . Could you measure on a reamer where you need to be with the size ? Stop short and finish with  a smoothing broach.  Reducing the staff would feel safer for me and normally easier to replace if things go wrong . 

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tomh207 Super WRT Addict

tomh207

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3 minutes ago, Kalanag said:

Well, there seems to be no other option than purchasing a reamer that I will never need again. I‘m not happy with this idea (yet).

Can a cutting broach do the job?

Well I’ll throw tuppence in the pot, the knowledgeable folks will hopefully chime in. A cutting broach is basically a reamer with a taper, I would think this would be what you would want for this but I may be wrong. A reamer is parallel and would be more for making a true hole. Saying that I think there are also tapered reamers kicking about for things like morse tapers.

 

Tom

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Neverenoughwatches Distinguished Member

Neverenoughwatches

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Posted
1 hour ago, Kalanag said:

Well, there seems to be no other option than purchasing a reamer that I will never need again. I‘m not happy with this idea (yet).

Can a cutting broach do the job?

I think that is what nev was meaning, reamer just being another term. I wouldn't be too happy either. 

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Neverenoughwatches Distinguished Member

Neverenoughwatches

Posted
Posted
2 hours ago, Kalanag said:

Well, there seems to be no other option than purchasing a reamer that I will never need again. I‘m not happy with this idea (yet).

Can a cutting broach do the job?

Do you have smoothing broaches that you can mark up the diameter on, so you have a gauge to work to. I do this when opening up a barrel hole so i know when to stop.

4 minutes ago, nevenbekriev said:

Yes, my english doesn't make difference between reamer and cutting broach. I try to improve it here...

Its ok nev those 2 terms are more or less interchangeable where ever you come from.  Reamers are often associated with their use in jewelling tools but some people also do call them broaches . Broaching and reaming mean the same, to open up a hole. Broaching a subject would be to open up a discussion usually a difficult one.

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CYCLOPS WRT Addict

CYCLOPS

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Posted

the roller or staff needs to have some taper to fit tight, you will use tapered reamers again and again in the future I'm sure, I don't know how you will hold the roller to do this maybe a pinvise.....be careful not to remove too much and hopefully the hole will not get out of round

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Kalanag Super WRT Addict

Kalanag

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Got this set of carb jet broaches (0,4 - 1,6mm) for just €9,- (shipping included). They worked well for the cutting. After finishing with a smoothing broach the result is fine 🙂

IMG_8721.thumb.jpeg.1eb1eca383c4b786ee810ff3b226bf09.jpeg

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