Broken centre wheel pinion

[Edmund]

Dear fellow watch enthusiasts,

Here we have a senior patient whose only ailment is a broken centre wheel pinion (two of its ten leaves are missing). Please have a look by yourselves.

The watch is a 1890s Straight Line 15 Ruby Lever Winder ('Ligne Droite Remontoir Ancre 15 Rubis') with a very large 24 ligne (54 mm) movement. The dial maker's ('Widmer') is the only maker's mark, concealed on the dial's back.

My theory is that the damage to the pinion was caused by the sudden release of the barrel. A broken mainspring was lodged inside with unusual thickness and length (0.27 mm, 74 cm) for this barrel size (21 mm), which probably made it subject to too much tension. The replacement mainspring (0.23 mm, 64 cm) that has now been fitted is more suitable according to my calculations. The pallet fork and the impulse jewel were disengaged, but this was easy to correct (the balance wheel was repositioned as shown in the photo), and the going train is now back to working condition except for the centre wheel pinion.

I took some additional measurements that could become useful:

Centre Wheel outer Ø: 15.52 mm.
Centre Wheel inner Ø: 3.33 mm.
Centre Wheel arbour length: 12.08 mm.

I would ideally like to obtain the spare parts to fit myself. I know some of you will say this is too difficult or too costly or not worthy. However, I also know there must be some connaisseurs out there who will empathise with my urge as a learning collector and watchmaker and hopefully will provide me with some practical guidance.

I realise my interest in antique pocket watches may not be shared by a majority of members of this forum. In that case, if there is any other online forum or club that you can recommend then that would also be appreciated. Perhaps you know someone in the area of London who can help.

Many thanks in advance for your valuable comments.

[szbalogh]

Need all dimensions to look for a good replacement. 

Dedendum circle and whole depth for the teeth. Tooth length and diameter at the bushings6jewels are also needed. 

Also measur the diameter at the gear mounting shoulder. It is much harder to mount the gear on a small shoulder.

 

Edited October 30, 2016 by szbalogh

[Edmund]

Dear friend, do the following sketches help?

[szbalogh]

8 hours ago, Edmund said:

Dear friend, do the following sketches help?

Yes, i will look around in my stock.

[szbalogh]

Sorry mate, dont have even a close one :/

[praezis]

The leaves can be built up by laser welding. I can supply an adress by PM if requested.

Frank

[Edmund]

Hi Frank, many thanks for your suggestion. This seems an interesting alternative to the replacement of the pinion. By all means, please get in touch by PM and I will analyse this option.

[Edmund]

I am responding to myself. Dennis Bacon (pseudonym 'Max Cutmore') offered the following advice on his Pocket Watch Handbook:

Quote

If a pinion is missing or broken, the only satisfactory repairs are

to file a new part to mesh correctly with the wheel,

to find a new pinion on a staff and adapt the staff to suit,

or to get a professionally made pinion and staff.

 

On 01/11/2016 at 7:27 PM, praezis said:

The leaves can be built up by laser welding. I can supply an adress by PM if requested.

Frank

 

Mr. Bacon seemed to disagree with this option:

Quote

The loads on pinions are too great to be able to repair a tooth satisfactorily, and the effort is hardly worth making.

 

Edited November 30, 2016 by Edmund
typo