Seat tube modified for expander post: returning to original standard bolt clamp?

I would like to ask a framebuilder how big a job it is, and what sort of price range I'd be looking at, to return a seat tube to a standard bolt clamp set up?

Some background: I've been mulling over buying a lovely and very rare vintage bicycle from the 50s or 60s (seller not clear). It had an illustrious and charming life until it changed hands to an owner in 1970 who had the original stunning handpainted details and black colour repainted. Disappointing, but ok. Then on closer inspection of the photos, I noticed there was no bolt to tighten the seatpost. I reread the text and the fact that that person had had modifications made then before the respray, which included it having a 'seatpost expander'. I had to research what that was and think this thread from the roadbikereview forum explains it and the typical problems it cause.

I cannot believe anyone would do this to a frame. None of the other frames of that brand have it. If the bolt thread dies, rusts, or the post needs replacement, I am stuck.

So I would like to find out first how much of an issue it is to have the bike returned to its original state.

The image here shows the (blue) bike in question on the left, while on the right how it would have looked and how I would like it to be.

I'd really appreciate any thoughts or opinions!

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What an odd thing to do, £70 for the seat bolt and maybe £50 to tidy up beforehand?

Thanks! That already helps quite a bit, because its the cost that bothers me the most and helps me decide for or against buying the bike.

Can such additional heating processes weaken a tube? (I clearly have no idea...: ))

Steel is pretty forgiving from that era. I'm from the 70's (my cycling era) and stuff like 753 had to be silver brazed at lower temps or it changed character

Vahrona might be a bit cheaper?

Is it something special? Don't see many 3 speed changers on the seat stay

Did it definitely start off looking like the black one?

I can’t see the bottom of the lug on the blue frame which makes me think the construction is a bit different.

It’s difficult to know what needs doing/will work without really knowing what’s been done and to know that it probably wants the paint removing.

To get it as true to the black one as possible it probably wants the lug replacing which isn’t an easy job if you want to keep the top tube and down tube intact*.

Pulling a tube out of a lug is alright, pulling a lug off two tubes simultaneously is a much harder task involving more heat and is something I’ve avoided ever undertaking.

You also have to deal with the seat stays, which looking at them again look quite different between the frames, on the black one the taper seems longer and the cap over hangs a bit, on the blue one they seem stubbier and there’s no over hang. Again, would suggest the two frames never started out identical.

What an odd thing to do, £70 for the seat bolt and maybe £50 to tidy up beforehand?

To whack a binder maybe but thats not really doing a proper job of it.

Yes, a René André 700c randonneuse. Seller in Paris wants around €1100 for it, which is big money for me, but it is lovely. I thought the price would be ok, since no components are needed, but I see it would involve added costs.

I'm in Germany, so my question was initially just about seeking advice. My first language is English, so I end up on English forums. Sorry - now I wish you were around the corner!

Anyway, it seems the job wouldn't be unrealistic, which is good to know.

Thank you!

Ah, I see. What you're saying makes complete sense. Quite a big project! There is some speculation that the frame may have been built by the great Robert Ducheron for André, which would make it a one off, perhaps. The head tube lugging looks similar to another Ducheron I've seen online and is completely different to anything I've seen elsewhere. Another André was my only comparison, but you have clearly spotted more details than I have.

Do you have an opinion on seatpost expanders? Is it ok? Ot too hard to comment on. Beginning to think it might be best to leave alone...

Ah, OK. I thought someone had butchered a 1950's Pennine or similar UK frame.

Moser and others used expander seat posts BITD, I've got a Moser with some nice Oria tubing in the shed so couldn't have been that bad...

Interesting thanks. Something to think about.

Well, most Ducheron frames I see online have standard clamps. However, I've just spotted this on a French forum thread, which apparently isn't adjustable at all. So perhaps this may not be one of the modifications that owner made and it may be original. It could only mean researching the expander history to have an idea, I guess.

The Ducheron frames are stunning though.

I don’t think they are the worst thing in the world, but the ability of a thin walled seattube to retain the expansion would definitely be a worry and unless the seat needed to be particularly low (ie bmx frame) or the frame had been damaged in such a way that removing all the seattube projecting above the toptube was necessary and an expander was there only way to secure a post, I’d think they were better ways to do the job.

In this case, I’d be more concerned that the quality of finishing on the attachment of the brake cable hanger is err…particularly out of keeping with that which can be seen on the black frame, if you know what I mean?!

Yes, couldn't agree more. You want a bike so much, you don't want to look too closely at some unpleasant bits. I guess at that kind of price, one tends to rethink it all a lot more. If I see a lovely old British frame going for very little that has suffered a little, then I don't mind the love and care it needs.

But structural issues concern me too, because I really want to do light tours and everyday stuff - just really use it. Not own a collectors item.

Your thoughts have really helped me! Thank you!!