Broken pinion leaf

[torsion]

Hi all
I have a Haller & Benzing Westminster chime with a broken pinion on the first wheel time side , I was hoping to turn down the old broken pinion and use a piece of pinion wire of the correct leaf count and diameter ( 10 leaf and 8.2 mm diameter) on a 4mm arbor but I have been unable to find the correct pinion wire .
Has anyone got any suggestions.
Thanks Dell

[torsion]

Well I have been able to locate some pinion wire 8.2mm diameter with 10 leaf but am unsure about the best thing to do, either drill hole in a piece of the new pinion wire and sleeve onto arbor after turning old broken pinion ( if enough meat on pinion wire to drill 4mm hole ) or turning a new arbor from a length of pinion wire to make a new arbor, any advice would be much appreciated.
Dell

[brianw]

Hi Dell.
If there is enough metal available on the new pinion then I would drill it and turn down the existing arbor to fit the hole. You would need to be careful about concentricity.
I guess the professional way of doing it would be to make a new arbor out of the pinion wire, but you would have to heat treat it after fabrication and this may distort the arbor and you would still have to be careful about concentricity when refitting the wheel.
If you have enough pinion wire available you could just try both methods and see which one turns out best. It’s all good practice……
Regards, Brian

[torsion]

This arrived today ( see picture) but it is not 8.2mm it is 8.1mm , the pitch looks good against the broken one but only depthing will tell , I was going to cut a small length off drill a small hole through the same size as the pivots and assemble between plates to check , but as it’s .1mm smaller I am not going to do anything until I have had a reply from seller, so a few questions 1st would .1mm make much of a difference, 2nd there seems to be about 5mm meat below leaves and the old arbor is 4mm would 1mm ( .5 mm all round )be enough if I sleeve it , 3rd if answer to question 2 is no then would it be safe to turn old arbor a bit smaller , 4th if I turn a completely new arbor what is the best way to turn the leaves of as I am not sure doing it with the cross slide would work as I have never tried to turn pinion wire before ( it is bad enough turning a square to round on a watchmakers lathe) my thoughts are fit pinion wire in a drill and grind off most of the leaves , any suggestions greatly appreciated Dell.

[torsion]

well I have cut a length of pinion wire off and drilled a hole to check depthing and as can be seen by the video and it seems to be good, so the next thing is to decide what to do, I cut the test piece long enough to sleeve over the original arbor so I think I will try that first as if that doesn’t work out then i have plenty pinion wire left to make a complete replacement Dell. https://youtu.be/qocpDN0hWOQ

[torsion]

Well today I have replaced the pinion, I put old arbor in a drill and ran it against the grinder to remove the old damaged pinion then turned the rest down using a graver, drilled and reamed the new pinion wire to 3.99mm , then filed 2mm of one end of the pinion smaller to accept the wheel and tapered the end as it had to be drifted into place for a good fit , as I hadn’t got any loctite i soft soldered the pinion on after tinning the arbor, I also had to run a fine file along both edges of each leaf as the profile was not quite correct, as can be seen from video it now runs very smoothly, I am going to just install the going train and run it in the test stand for a week just to make sure Dell.
https://youtu.be/oFx1NjafQOU
Put just going train together to test for a week tick a bit loud because I had beat amplifier on
https://youtu.be/12AMIy7EEp0

[Anonymous]

Thank you for posting followups on your pinion wire topic Dell. I’ve been following your updates.
I know absolutely nothing about pinion wire or that it was even available so I’m learning about it from you. Very interesting following your progress!
I have read that pinion wire was used long ago but wasn’t aware that it was still available. Is there a supply house that stocks it?
Thanks again Dell. Very helpful.

Howard

[torsion]

Hi Howard
Thanks for your comments, as far as I know it is no longer available but it is often listed on eBay ( where I found some )but it took a while as it seems 10 leaf is not very common in the size I needed there seems to be loads of 7-8-12 in various sizes available so I was lucky to find some.
Dell

[Author]

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