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making horn push (SWB steering wheel) from scratch
#1
I'm trying to get a simple horn push onto the centre of an old-style steering wheel. Have no levers present and don't want them.
I know the nickel SWB hornpush is available from suppliers.

I can see I need to make a central wire coming up to a flat terminal in an isolated bush/rubber, but presuming that none of this is available to buy?

Is there a modern equivalent mechanism - did someone mention old mini - which I could make things up from from accessible parts? 
I can't quite visualise how/what a push will secure to - but know someone else must have done the same thing!
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#2
A chummy horn button screws onto a 'spigot' threaded 11/16" x 32 tpi.

I don't have one myself but always kind of assumed all the button does is touch and earth an insulated wire,  in which case the 'mechanism' would not consist of very much! The button is spring loaded.
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#3
ok, well that's a good start thankyou.
So if one used that button, presumably there is a spring inside the button to hold it off... and the spigot it is threaded onto is centrally drilled for the stud and connecting wire coming up column?
And has some sort of collar for the top of whatever you are pushing it into, after it then descents to the dia for a fit in the outer, which appears to be about 12.8mm?
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#4
Jon,

There is a stepped bush made of paxolin, or similar, pressed into the inner stator tube. Thro' a hole in the bush a wire to the horn is pushed through with a nipple soldered on. A short spring prevents the button touching the nipple until pressed, so completing the circuit.  Horn buttons of this type are difficult to find.
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#5
Well explained Chris!
Rarely seen an original for sale but Willie McKenzie sells repros.
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#6
I'm just scratching my head trying to work out the bit beyond the paxolin bush.
Plainly that can be made up for the larger diameter of the steering tube if stators are not in place (unless anyone has a really good simple indicators solution using stator tubes)
But does the top of the paxolin have the 11/16" thread Chris mentions, or else what holds the base of the horn push? which presumably must be two linked pieces for securing AND being held away with the spring?
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#7
The horn button screws onto the top advance and retard lever Jon, you could of course make a threaded boss to fit into the main steering tube but that would then rotate with the wheel and stress the cable. Far better to use the outer tube of the advance mechanism with either a bespoke threaded boss soldered to it or a modified lever. There are other way's using something like a post war morris horn push which could incorporate a dip switch but that would again need a bespoke mounting.
Black Art Enthusiast 
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#8
this is why I was confused... top pic is what I realise is a late-late pair with no attachment point above the lever:    
Bottom pic from Ian Moorcraft - thankyou - is a late-early pair!    
Presumably the early brass pair is much akin to the above in function.
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#9
Your top picture looks as though it has two bottom levers- you need a set as shown in the excellent bottom picture  Smile
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#10
Austin cunning with parts there post-1932.
But it's due to the exposed Chummy style horn setting ending, Tony.
I presume that probably shows up in the parts changes cards.
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