Compound gear repair

[dnhb]

A compound gear wheel has separated into its two component gear wheels. The smaller one, comprising the axle, was affixed to the larger (about 8mm diameter) at some 8-10 points around its centre hole with a few mm (of the hub), plus that end of the axle, protruding on the far side. I'd be grateful for advice on how to go about re-uniting the two parts. (it's actually part of a music box mechanism - I'm assuming the techniques are similar for watch gears....)

[mikepilk]

Pics ?

[dnhb]

Thanks for your interest, Mike. Photos attached.

[RichardHarris123]

It looks like a staff and the pivots are broken, I would assume the wheel is riveted on. 

[mikepilk]

4 hours ago, RichardHarris123 said:

It looks like a staff and the pivots are broken, I would assume the wheel is riveted on. 

Are the pivots broken, or are they just cone shaped at the end like Timex pivots?

Does the wheel just need pushing back on ?

[nevenbekriev]

Te pivots are OK, they simply are big. The wheel needs to be re-riveted.

[Neverenoughwatches]

On 12/24/2023 at 6:24 PM, dnhb said:

Thanks for your interest, Mike. Photos attached.

It just looks like a basic drive wheel,  pinion and wheel riveted together or pressed in held by friction. How loose is the fit ? you might be able to spread the rivet out again if its still intact or close up the hole with a domed punch to friction fit again.

[dnhb]

Thanks for your interest, Mike. Photos attached.

I can't see how to respond individually to each of your helpful responses, Folks, so this is a portmanteau response & 'thank you':  The Pivots are cone shaped at the end, not broken. Not sure what is meant by "spread the rivet out again" but it may well be that the Pinion of the smaller cog wheel was just a friction fit in the hole of the larger wheel. I'd come across the idea of closing up such a 'housing' hole with a punch before, but couldn't remember where and so wasn't sure how to do it without buckling the wheel itself.....

[Neverenoughwatches]

54 minutes ago, dnhb said:

Thanks for your interest, Mike. Photos attached.

I can't see how to respond individually to each of your helpful responses, Folks, so this is a portmanteau response & 'thank you':  The Pivots are cone shaped at the end, not broken. Not sure what is meant by "spread the rivet out again" but it may well be that the Pinion of the smaller cog wheel was just a friction fit in the hole of the larger wheel. I'd come across the idea of closing up such a 'housing' hole with a punch before, but couldn't remember where and so wasn't sure how to do it without buckling the wheel itself.....

Some components are held together by a flange that is attached to one of the parts . That part would be inserted through the hole and the flange spread out and folded over so it grips the adjoining part. Tbh this just looks like its friction fitted and would be inserted under pressure.  If the hole is slack fit it could be closed up with a wider domed punch. 

[CYCLOPS]

that wheel is press-fit onto the pinion, if loose you can flatten or peen the hole smaller with a round faced punch from a staking set, I hope this helps 

[dnhb]

On 12/30/2023 at 4:01 PM, CYCLOPS said:

that wheel is press-fit onto the pinion, if loose you can flatten or peen the hole smaller with a round faced punch from a staking set, I hope this helps 

I've just invested in an old K&D 600 series staking tool set in order to do this.....

On 12/30/2023 at 11:54 AM, Neverenoughwatches said:

Some components are held together by a flange that is attached to one of the parts . That part would be inserted through the hole and the flange spread out and folded over so it grips the adjoining part. Tbh this just looks like its friction fitted and would be inserted under pressure.  If the hole is slack fit it could be closed up with a wider domed punch. 

Thanks for explaining that - I've found an illustration on YT of this being done.

[CYCLOPS]

that is still one of the best staking sets, you won't be sorry you found it, there is a booklet/leaflet that explains how to use the different punches and stumps also....

[dnhb]

2 hours ago, CYCLOPS said:

that is still one of the best staking sets, you won't be sorry you found it, there is a booklet/leaflet that explains how to use the different punches and stumps also....

 Thanks. After a bit of research within this & other Forums, I thought the K&D Inverto facility was a key feature along with the reasonable availability of stakes & stumps, K&D's reputation and, as you say, the available documentation (e.g  https://archive.org/details/KDStakingTools/page/n17/mode/2up & at https://kanddinverto.weebly.com/junior-inverto-600.html). With no real idea about value for money (although I know there are other watch repairs I'll be using it for) but assuming it might be an appreciating asset in the long term, I paid £268 (inc P&P) for a set with 76 (out of 100, judging by the 'holes') stakes and 15 (out of 20) Stumps with a box albeit missing 2 handles & original latch but otherwise in apparently good condition. I could have bought a new, Indian-made boxed set for £375 with 120/20 items or waited for a complete K&D set to turn up but I feel, as you imply, that I've made the right decision- as they used to say of a Rolls Royce purchase: "the Quality remains long after the Price has been forgotten".

[dnhb]

On 1/3/2024 at 10:46 PM, dnhb said:

Thanks for explaining that [ i.e. "Some components are held together by a flange that is attached to one of the parts . That part would be inserted through the hole and the flange spread out and folded over so it grips the adjoining part. Tbh this just looks like its friction fitted and would be inserted under pressure.  If the hole is slack fit it could be closed up with a wider domed punch." ]

Bearing in mind your comment, on firing up my Adonstar magnifier I found that there was a 'castellated' flange at the end of the cogged pinion of the smaller part although the flange length wasn't long enough to be folded over on the far side of the big wheel once inserted. However, your comment caused me to push out the flange from its slightly folded-in state - which I did using a round nose hollow stake (K&D #80) - press the piece into the larger wheel & then re-tighten the connection with the #80 stake. The compound wheel is now re-installed in the music box mechanism which is now working !