Suggestions for Making Replacement Lucas Car Horn Button Trim

[James AlfordParticipant @jamesalford67616]

I wish to make a replacement metal trim for a Lucas horn button. It is the chrome metal circle in the picture below. It is a square u-shaped cross-section, made of thin metal. The channel is approximately 3mm to 4mm wide.

Does anyone have any suggestions how I could make this, other than by carefully tapping a piece of metal around a former?

Thank you.

James

[DC31kParticipant @dc31k]

Can you make a dimensioned pencil drawing of it and upload.

I am puzzled by the ‘square U-shape’. Does that mean vertical left leg, horizontal base leg and vertical right leg?

On an industrial scale, it would have been pressed/stamped. Expensive tooling but amortised over 100,000 units, it is cheap.

If the gap between the two legs of the ‘U’ is an artifact of its production method rather than essential to its function, make from solid bar. Turn OD, bore ID, part off. Stainless can be made to look like chrome, or perhaps nickel plate brass or steel.

[Michael GilliganParticipant @michaelgilligan61133]

For a one-off [or for a potentially lucrative short production-run] … I would look at electroforming.

MichaelG.

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Edit: __ In fact, responding to your question prompted me to download this very useful document for my own future reference:

https://nickelinstitute.org/media/1674/electroforming_auniquemetalfabricationprocess_10084_.pdf

 

[DC31k]

On DC31k Said:

Can you make a dimensioned pencil drawing of it and upload.

I am puzzled by the ‘square U-shape’. Does that mean vertical left leg, horizontal base leg and vertical right leg?

[…]

Presumably, the cross-section is an inverted square U-shape

MichaelG.

[David JuppParticipant @davidjupp51506]

Try searching on the Lucas part number.  It’s surprising how much new old stock is still available, and often not expensive.  Same switch might have been used with different colours but same metal trim, or with a badge in the centre.

[noel shelleyParticipant @noelshelley55608]

Michael beat me to it ! my first thought was electroforming ! Machine from solid stainless or brass and plate ! A similar unit was used on the Morris J2 van ! The tube down the middle would break ours did it in Sweden ! Noel.

[bernard towersParticipant @bernardtowers37738]

Got to be worth a try as pattern rplacements on the net are £250.00 plus!!!!!!!. A drawing would be good.

[Nigel Graham 2Participant @nigelgraham2]

Electroforming may be effective but presumably we are looking at what can be done at home in a reasonably equipped by otherwise conventional workshop?

In which case, really, the only options are folding it over a steel former, or turning it from a solid disc.

[Michael GilliganParticipant @michaelgilligan61133]

Why would electroforming not be possible in the home workshop, Nigel ?

… many people do electroplating

MichaelG.

[Rod RenshawParticipant @rodrenshaw28584]

If no spares are available it might be worth seeing if something intended for use as a watch or small clock bezel might fit. Or perhaps the watch/clockmakers on the forum could advise how they would go about making a bezel, and the method could be used to make one of the size needed.

[Michael Gilligan]

On Michael Gilligan Said:

Why would electroforming not be possible in the home workshop

I think this is a variation on the same theme:

If you had a need for steam passages to follow some twisy route not amenable to conventional machining, it could offer possibilities.

[Michael GilliganParticipant @michaelgilligan61133]

Fabulous video !

… and orders of magnitude more complex than this little job would be.

Just machine the internal form on a bit of Aluminium

Plate-on a suitable thickness of Nickel

Remove the bulk of the Aluminium mechanically, and dissolve the remainder

… It’s well-proven, being the way they make bellows.

MichaelG.

[Grizzly bearParticipant @grizzlybear]

Nice one Rod,

Thinking outside of the box.

Bear………..

[BazyleParticipant @bazyle]

No-one has mentioned trepanning from sheet.

I think I’d perhaps roll some thick nickel wire into a loop, hammer it flatter if that didn’t risk distortion, solder, then machine off the extra bits.
If you ended up outsourcing the above method would be a silver smith’s route and being so routine for them possibly cheaper in solid silver than a machine shop would charge for a special.

[noel shelleyParticipant @noelshelley55608]

I think it was ME who carried an article on electroforming of copper for an aeroengine cooling jacket ? Noel.

[Michael GilliganParticipant @michaelgilligan61133]

I have to confess that Nickel Electroforming, whilst an obvious technical solution, is looking rather costly.

If anyone knows a cheap source of the chemicals, do please tell.

 

MichaelG.

[noel shelley]

On noel shelley Said:

I think it was ME who carried an article on electroforming of copper for an aeroengine cooling jacket ? Noel.

That’ll be Stephen Wessels’ article in ME 4579.  Mr Wessels is a very talented man:

 https://www.youtube.com/watch?v=sJLhpvOY3v0&t=13s

I would electroform in copper and then nickel plate

Rod

[Michael GilliganParticipant @michaelgilligan61133]

That’s a truly humbling video, Rod !

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

This video is an advertisement by a U.K. Supplier:

I offer it only because it is detailed, and blissfully silent !

… take from it what you will.

MichaelG.

.

https://youtu.be/Hn_-4dihAdY?feature=shared

 

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Edit: __ I took this [it’s free]
https://www.goldn.co.uk/copper-electroforming-calculator/

[James AlfordParticipant @jamesalford67616]

Thank you for the suggestions. I am not sure about turning the piece from solid or trepanning it, not least because of the thinness of the material and my ability.

The sketch below gives the sizes. The split at the top is to allow the piece to be opened up slightly to get onto the button.

 

[Martin KyteParticipant @martinkyte99762]

I would turn it out of solid. The ‘hollow’ back is not really needed I suspect. I would turn the shape on the face of a piece of bar. Boring the centre deeper than the shape and then turning the outer diameter to size. Form the curve and part off. Piercing saw to create the cut. The diameters may need adjusting down a tad to effect the ‘nip’ onto the button.
regards Martin

[Michael GilliganParticipant @michaelgilligan61133]

Apologies if I am being thick, James … but is this the Lucas model you have?

https://www.holden.co.uk/p/horn_ind_centre_steering_whee1

 

If so … I am confused by your reference to a split … which I can’t see in their photo

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

[ correcting myself ]

No, I don’t think that’s the one … although there does seem to be a strong family-resemblance.

MichaelG.

[James AlfordParticipant @jamesalford67616]

Michael. 

That is similar,  but a little different. The version I am working on is from the mid-30s. The original ring is pressed somehow from a strip of metal. If it had a solid back, as suggested in a different post, it would probably interfere with the mechanism behind it.

James.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the clarification, James

Electroforming still gets my vote

… but maybe only because I’m keen to see it done 🙂

MichaelG.

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