Removing old crown in headlamp

[PeeWee]

Is there an easy way to remove the old “crown “ in the headlamp of my R51/3 ?
The reason I ask “easy” is because the headlamp is already done with paint an all, and I didn’t see on time that the crown was slightly damaged .
All ideas are more then welcome

[Micha]

I may be wrong here, but in my humble opinion it is caught to the inside of the lamp's shell with a kind of thin metal thorns that go into place in the crown and then you bend them. If so, they will have a tendency to break of course (because who knows how many times this has been done in the past and now there will be material fatigue).
Mine were in this condition and of course broke, I had to improvise threaded rods in bronze soldering.
Life is hard there is no doubt about it.

[PeeWee]

The crown is electric welded in place in the headlamp.
Two of my thorns are broken and I thought the only solution was to put in a new crown.
A solution to recover the thorns is always welcome.
You say that you had to improvise with bronze soldering ?
Will it hold on the material of wich the crown is made ?

[Micha]

Well there you caught me. Sorry, I do not remember anymore.
What is this crown made of? If it is an aluminum-like material - I would be very careful and not approach it with soldering or welding of course, because apparently it is a type of a zinc-based alloy. Problematic material.
Are pictures available of this disaster?

[PeeWee]

No pictures available at the moment but I think as you say it’s zinc-based .
My idea is to saw of the welding points with a small blade or something like that, and then glue on the new crown with metal glue but perhaps there are members here with other and better idea’s

[malmac]

I have attached a couple of photos of a headlight shell I have which is a 1960's vintage.
So may be different to your 1950's version but probably not.

You can see where they have spot welded the piece in place.
I could only see two spots but I would assume three or even four.

Given that the chrome cover covers the spots (then again did the 51's have that cover - maybe not.
I was going to say you could carefully drill out the spot welds and then rivet a new part in place.
The chrome cover would then cover the rivets.

Another thought is to fabricate a tube with tangs that fits neatly over the old part and secure it to the old part with rivets or small screws. Use the tangs on the new part to retain your switch.

I am going to modify mine and use 4mm studs instead of the tangs and then small nyloc nuts to secure switch in a more dignified manner.
Not original but an improvement in my mind.

Mal

[PeeWee]

Thanks for your idea’s malmac
It’s something to give it a try on both the possibilities.
I’m already thinking ...
And yes, mine has the chrome cover too on the headlamp