Austin put it together, why can't I get it apart?

[bobthompson]

I am working on an RK front windscreen. I wanted to replace the glass, but the screen would barely open - so I have removed the whole frame from the car. Bottom rail is off and glass removed. Despite soaking the assembly in Diesel and then Plus Gas, I can still only get 2" opening of movement. It appears there is a steel tube inside the brass chromed outer tube that is the top rail. The inner tube seems to be one piece for the full width. I can tap it about 1mm sideways at one end and the other end moves. I can just see the inner tube through the 3 wiper mounting holes and it is just moving slightly. If I lever the frame bracket up at one end, the other end moves with it. This all suggests it is one piece?
I cannot for the life of me see how it was put together! There is no sign of welding of the frame bracket to the inner steel tube, which is what I  expected.
I am hoping that somebody out there must have taken a frame apart for repair or re-chroming, how is it done?
Thank you in anticipation.......

[Peter Johnson]

Does this help at all?

   
   

[bobthompson]

Thank you, very interesting! That is what I expected it to be. However I am convinced mine has a tube all the way through, as I described.
I could try hitting the frame brackets harder to see if they come apart like yours, but I would have expected with all the diesel and plus gas they would have given in by now? Why can I see a tube within a tube through the wiper mounting holes? Unless the brass outer tube is double skinned?

[bobthompson]

Does anybody else have any theories, Please?

[Chris Garner]

Bob,
I'm afraid I can't be much help but the disassembled windscreen shown in Peter's photos are exactly as my RK screen when I took it apart. The side irons only have a short piece of tube fitted into the top rail. It sounds as though someone at some time has done a " modification " , but I can't see how it was done (?)

[bobthompson]

Thanks Chris, can you confirm if there is a full length brass tube within the chromed outer tube? If so my steel "pins" must be seized inside the inner tube.
Bob

[Mike Costigan]

Peter's photos show the standard method of construction on both RK saloons and AD tourers; the steel 'pins' are a reasonably tight fit in the brass tube with insufficient clearance for a second tube. If your assembly has got a second tube installed, then the pins have been replaced or turned down.

[Colin Wilks]

Hi Bob
Heat could be your friend here. Brass has approaching twice the coefficient of linear thermal expansion of steel.

[Dennis Nicholas]

Thanks Colin for that valuable fact.......just the sort of info we need......I have often wondered about such things when doing various jobs.......too lazy I suppose to look it up myself but I do spend a vast amount of time researching subjects.
A plea to all with specialist knowledge....please do add these useful nuggets of info........after all he could have just said "use heat" The info will probably get said many times over but it is more likely to stick in the mind for that and become more "general knowledge".
I like being a granny being taught to suck eggs.

Dennis

[Colin Wilks]

Can't claim any specialist knowledge. I just wondered what would happen with heat, which is an obvious tactic if hitting it doesn't work, so I looked it up.
Be interesting to know if you've got it apart yet Bob?