Fitting new balance staff

[omx5o]

Hi,

I've successfully removed a broken balance staff using a K&D balance staff remover. I'm now in the process of fitting the new balance staff and following one of Mark's videos. Using the correct rounded punch I have the balance staff fitted so that it doesn't fall out, however the staff does wobble slightly in the hole of the balance wheel. I've been applying gradually more force with the hammer, but don't wish to over do it, as advised in Mark's video. So, should there be any wobble at all or should the staff be firmly fitted to the wheel? I guess it should be a firm fit, but I'm cautious about applying too much force.

Peter

[rogart63]

Have you used a flat punch after the rounded punch. How loose was it before you riveted it? 

[oldhippy]

Are you sure, you are fitting the correct staff? The new staff should be secure.  

[Chopin]

Balance staffs are tightly friction fit so it shouldn't move around at all.

[omx5o]

I applied a bit more force and it appears to be firmly fixed. I can also see some deformation of the shoulder now so I think it's properly on. I followed it with the flat punch and it's all looking good.

Thanks.

[clockboy]

4 hours ago, omx5o said:

Hi,

I've successfully removed a broken balance staff using a K&D balance staff remover. I'm now in the process of fitting the new balance staff and following one of Mark's videos. Using the correct rounded punch I have the balance staff fitted so that it doesn't fall out, however the staff does wobble slightly in the hole of the balance wheel. I've been applying gradually more force with the hammer, but don't wish to over do it, as advised in Mark's video. So, should there be any wobble at all or should the staff be firmly fitted to the wheel? I guess it should be a firm fit, but I'm cautious about applying too much force.

Peter

As a matter of interest how did you remove the old staff. The reason I ask I have found some staffs if removed by pushing them out distort the balance hole. As a result I now remove some of the old staff rim on my lathe before finally pushing out the old staff. 

[JohnR725]

Often a forgotten step did you measure the new staff versus the old staff? It's commonly assumed when buying a replacement staff that it will be of the correct size and often times it's not.

[omx5o]

40 minutes ago, clockboy said:

As a matter of interest how did you remove the old staff. The reason I ask I have found some staffs if removed by pushing them out distort the balance hole. As a result I now remove some of the old staff rim on my lathe before finally pushing out the old staff. 

I used this balance staff remover with a staking set. What sort of distortion of the hole did you get? Afterwards the hole itself looked fine. There was a depression on the hole edge on the side where it was riveted, however the depression looked very regular and I assume that is just the original shape of the balance arm/hole.

Interestingly the K&D remover didn't extend enough to hold in the M.K.S. staking set. So I used a couple of rubber washers (in the image) to allow the tool to be firmly fixed in place.

I did get a slight distortion of the balance arms which caused the wheel edges to no longer be parallel, but I reversed it using a large stump and flat punch just using the pressure from my fingers.

Edited May 20, 2018 by omx5o

[JohnR725]

What watch did this balance come out of and what staff number did you use?

[omx5o]

15 minutes ago, JohnR725 said:

Often a forgotten step did you measure the new staff versus the old staff? It's commonly assumed when buying a replacement staff that it will be of the correct size and often times it's not.

Yes, the dimensions matched the old staff. However there was a difference with the roller seat. The old staff didn't have a roller seat at all and the roller was just positioned at the correct point along the staff. The new staff has a good sized roller seat which extends to the same point that the roller was attached on the old one. Apart from that it all measured up.

[omx5o]

3 minutes ago, JohnR725 said:

What watch did this balance come out of and what staff number did you use?

The watch is a Waltham 18s 1883 from about 1900. I ordered a H588 as a replacement staff.

[JohnR725]

Then of course there's the other problem what makes you think the original staff was the correct staff? This is where usually I measure the old staff the new staff and I look at the reference books I have the make sure that all of them agree. Because unfortunately over time inappropriate things have been inserted into the watch and even if you get the right staff things may not fit. The other thing happens for American pocket watches are there also conceivably more than one staff a lot of time so be size variations and the definitely be pivots size variations.

[clockboy]

If the balance hole has not been distorted then it must be the balance staff's riveting shoulder is to small.