Reducing the butting in a head tube

I've just got my hands on a LeMond Alpe D'Huez, 853 steel 57cm etc. There is currently a appears to be a 1" headset, but the butted walls where the cups fit are really quite thick whilst the main tube is considerably larger. I was wondering if it was at all possible to take out 3mm of the butting in order to accommodate a larger 1 1/8" headset. This may be a really stupid question, but my older Raleigh frame has a straight gauge head tube and I've never had any issues with flex etc. As to why I'd want to do this, simply I have a bunch of 1 1/8 carbon forks which I'd like to utilize, otherwise I'm looking at some Columbus minimal's which are 150+

Cheers,
Joe

May be fairly simple using an expanding reamer of a suitable size. This would be fairly laborious but also a fairly safe way of doing it.
I suspect while machining it would be the quickest way, it may not be cost effective taking into account the need to make some sort of jig to hold the frame.

Seems like a lot of faff, there are 1" forks out there.

I think you may find that in practice it's a lot of material to remove, possibly more than what a reamer is capable of?

Could maybe be up to the job, but more likely would be a suitable sized drill bit, using a reamer to clean up the area afterwards. The frame would have to be secured in place with a jig, All increasing the cost...

I experienced something similar trying to remove some butting in a very short fork steerer, as I couldn't get a quill stem in past the minimum insertion. The guy I took it to said it was a fairly big job, and he was only removing a minute amount of material.

Id be interested to see how much you can get milling done for.
I machine work I went to was ridiculous with basic lathe work I wanted done... non bike related.

Simple answer, no
The outer diameter of the head tube would have to be at least 36mm for there to be enough meat left after machining, a reamer wouldn't be able to remove that kind of material, leaving boring or circular interpolation which would be incredibly difficult to set up for, therefore expensive. Basically just find some one inch forks

Or have a framebuilder change the headtube for a 1 1/8 one...

That extra material is there to allow for the distortion from welding, you'll probably find that the head tube is slightly oval at the tops, not a problem as they've added material to allow you to ream it round. Even if there was just enough material to allow for a larger headset size, your end up with thinner walls at front and back of the head tube, and a good chance it will split.

A guy I know has a klunker/cruiser with this set up. He says the headtube was particularly chunky when he bought the frame and he "machined" it to 1/18" and fitted a fork with disc mounts.

He does some sort of engineering degree I think though so probably has access to a good range of tools.

Thanks for the responses folks! The outer diameter is 36.5mm (measures with a caliper) so I reckon it is doable. I think perhaps a drill would be best but as you most of you say securing the frame would be expensive. I guess I may just have to bite the butting and find some 1 inch forks, until I can find a way of doing this effectively.

Fucks sake, a frame builder has answered your question and strongly made the case that this is not a good idea. But hey ho... at least this level of Darwinism may be of benefit to the gene pool.

I'm a student, the chances of me ever being able to afford to do it is minimal, I will be looking for some 1 inch forks, don't you worry.

https://www.varonha.co.uk/repairs/

Seriously, new head tube, 90 quid. Thats the price of a decent set of 1 inch forks anyway

36 is the diameter of 1 1/8th 853, so its not a totally stupid idea, but as you've stated that it sucks in below the cups I still think you'll run into distortion issues.

It won't be a drill you would need, they're designed to drill down into material, you're just attempting to remove material on the id, so its a fuck off end mill or a swathing cut on a circumference cutter. You then have to ask how you're going to hold the frame whilst cutting, plus centring. None of these are insurmountable, but time consuming. As its a complete frame already, you will need a big mill to do the job, I have 3 mills and only the Bridgeport would be able to fit it I'd imagine. So...... When you add up the costs involved in set up and machine time, a new head tube from winston (most experienced frame builder in london) at 90 squids sounds like a much more cost effective way of going about it.

I'm in no way against cutting things up and trying to put them back together, I think its a great mindset to have, to ask "what if I......" I just get the feeling that you're not doing this for fun, but actually just want an 1 1/8" fork, and the best way is to go to Winston.

Engineering students are the bain of my life ;)

While you're here, are you still not doing any little jobs/focusing on frames? I just want some small bits and bobs doing. Will go to Winston if not but would rather come to you first

Winstons going to Cuba next week

I second this. Would like mudguard eyelets installed - front and back.

Lol I'm not in a rush, I just fancy a drink when I'm riding at some point in the future

And I could do with a new paintjob..

Can we make a list?

Engineering students are the bain of my life ;)

Oh hai!

And I could do with a new bike in XXXXXXXL

Tandem

I'm not engineerist, some of my best friends are engineers....

I'm just jealous really....

Afraid not, between you and me I'm stopping doing almost any custom work either in the next month. Winston is your best bet, but he is permanently on holiday. Fish ain't going to catch themselves....