From thrreaded to threadless

[Gattonero]

So it happens that I've a set of forks, 1" threaded. They are fully chromed Columbus, correct replacement for a classic Cinelli of mid-90's.
They are expensive to buy new.

They are for a 62cm frame I guess, the steerer is pretty long.
A.t.m. I have fitted the original forks, threaded and the correct size for the 55cm frame. Those 62cm sized forks are NOS and kept as spare, I had them for nearly nothing.

Now here is the rub.
I do have two Grammo ti 1" a-head stems, and a Record 1" a-head complete headset.
Could quickly swap the headset upper section, fit a-head forks and stem. Have another set of Cinelli 64 bars and C-Record brake levers, shifters are DT so it's all pretty easy for me.

BUT

The 62cm forks have the steerer long more than enough to clamp the stem, if wasn't for the last 40mm-or-something threaded, of course. The Grammo a-head stem has a pretty high stack (55mm if I'm not wrong?) and would clamp slightly more than half in the last smooth portion of the steerer, and a bit less than half in the threaded section. There is about 15-20mm of excess threaded steerer.
I do not like the stem being clamped on the threaded section. Is not good, not safe, will mark the stem and damage the thread on the forks.


So let's hear what the master builders would recommend.

Replace the steerer?
Cut the threaded section and add that 20-30mm brazing on an insert?
Fill the thread with brass and give it a go on the lathe?

What do you think is the quickest way?
I imagine that replacing the steerer is PITA as would foul the chrome, plus being a relatively long job; easier to sell the forks and get new ones, I'd say.
The last two options?

[Eric Estlund]

Threaded headset and stem.

[Gattonero]

Threaded headset and stem.

That what is already there. It all works fine.

Aside from the option that one may like or not, the reason I am asking is to know if is possible that mod on the forks, and which would be the best way.
I'd like to know from the framebuilders what they would do, or the reason why not doing it.

[e-RICHIE]

So let's hear what the master builders would recommend.

A master builder has already replied.

[Gattonero]

A master builder has already replied.

mr. Sachs, I've no doubt that mr. Estlund knows what is doing.
And right for this reason, is it too much asking "why"?*








(* ATMO isn't enough, cheers )

[P K]

Just to clarify - are you asking the question: Would it be OK to clamp an a-head stem on to half a section of threads from the threaded fork?

[e-RICHIE]

mr. Sachs, I've no doubt that mr. Estlund knows what is doing.
And right for this reason, is it too much asking "why"?*








(* ATMO isn't enough, cheers )

Any option remotely similar to the three asked about is bad engineering, bad science, bad, and a bad use of a good man's precious time atmo.

[Gattonero]

Just to clarify - are you asking the question: Would it be OK to clamp an a-head stem on to half a section of threads from the threaded fork?

Nope, the reason I'm asking if is possible to "extend" a steerer is right to not clamp a stem onto a threaded section.

Any option remotely similar to the three asked about is bad engineering, bad science, bad, and a bad use of a good man's precious time atmo.

I read between the lines then, you cannot be bothered. Same way I do not do certain repairs, but I do give a brief explanation when politely asked

[e-RICHIE]

I read between the lines then, you cannot be bothered. Same way I do not do certain repairs,

I think bothered is a very personal term. When someone asks me a similar (to yours) question, they normally get a reply that is like Eric's.

but I do give a brief explanation when politely asked

I thought Eric's was polite. I was simply pointing out that he had replied.

[Gattonero]

Is still not satisfactory.

One that has no time, shouldn't even waste time to reply here, if is really such a silly question.

To me, as a professional mechanic but not framebuilder, the inner sleeve+extension brazed on is not such a silly mod., similar concept as a frame repair.

[e-RICHIE]

Is still not satisfactory.

One that has no time, shouldn't even waste time to reply here, if is really such a silly question.

To me, as a professional mechanic but not framebuilder, the inner sleeve+extension brazed on is not such a silly mod., similar concept as a frame repair.

Well I'll concede to that if it's your POV. So if there's a commercial framebuilder who thinks that's an agreeable solution, I'm sure he'll/she'll chime in atmo.

[edoz]

I'm far from a master builder, but I would definitely not do any kind of steerer tube extension. The penalty for failure is too extreme IMO, especially when the only purpose is to save a few bucks.
I'll add in all sincerity (and not trying to just be a jackass) that if you have to ask about this sort of modification, then you certainly shouldn't try it as you don't have a full understanding of the engineering and risk involved.

[e-RICHIE]

PS Germane to this is a t shirt a pal of mine has.
It reads Do you want help, or do you want affirmation atmo.
For the record, there's no atmo on the t shirt. But it is a precious garment.

[P K]

I print T-shirts, let me know

[Gattonero]

I'm far from a master builder, but I would definitely not do any kind of steerer tube extension. The penalty for failure is too extreme IMO, especially when the only purpose is to save a few bucks.
I'll add in all sincerity (and not trying to just be a jackass) that if you have to ask about this sort of modification, then you certainly shouldn't try it as you don't have a full understanding of the engineering and risk involved.

Let's assume the job can be done.
How much will cost, compared to a new set of Columbus forks with Cinelli sloped crown and dropouts, then chromed. Ain't no few bucks there, although you're right that safety goes before everything else.

And what is the risk of failure? I'm genuinely curious. Distortion in the existing material (steerer), or not sufficient area to braze the inner sleeve? Too awkward?
I am considering that the extension will cover the upper 1/3 of the stem clamping area, so the stem itself acts as additional brace.
Surely I would never consider a steerer extension that would go under half or the entire stem. C'mon!

[Gattonero]

...
It reads Do you want help, or do you want affirmation atmo.
....

I see that on the face of many people with the wrong carbon bike

[e-RICHIE]

I see that on the face of many people with the wrong carbon bike

As with frame repairs and mods, there are the carbon bikes that work and have a track
record of folks who have made them, and there are poorly conceived versions of same.

[Will Neide]

Let's assume the job can be done.
How much will cost, compared to a new set of Columbus forks with Cinelli sloped crown and dropouts, then chromed. Ain't no few bucks there, although you're right that safety goes before everything else.

And what is the risk of failure? I'm genuinely curious. Distortion in the existing material (steerer), or not sufficient area to braze the inner sleeve? Too awkward?
I am considering that the extension will cover the upper 1/3 of the stem clamping area, so the stem itself acts as additional brace.
Surely I would never consider a steerer extension that would go under half or the entire stem. C'mon!

Sounds like you have some nice forks you want to save, but I really think that your plan is a bad one. I highly doubt any builder with a reputation would do what you are asking to be done. I'm a big fan of trying to re-use old stuff, but this one definitely falls into the "no go" for me. Better to shelve those forks for a better project one day. It's not worth risking your safety or those nice forks for this experiment, IMO.

[Gattonero]

As with frame repairs and mods, there are the carbon bikes that work and have a track
record of folks who have made them, and there are poorly conceived versions of same.

True.

The difference is that very few would make carbon forks on their own, and "off the shelf" ones are ready available for not much money. Besides, carbon isn't as predictable as steel.

I am not that kind of guys who has a wrong carbon bike and asks for an extension of its steerer. There is a little bit more behind a keyboard

[Gattonero]

Sounds like you have some nice forks you want to save, but I really think that your plan is a bad one. I highly doubt any builder with a reputation would do what you are asking to be done. I'm a big fan of trying to re-use old stuff, but this one definitely falls into the "no go" for me. Better to shelve those forks for a better project one day. It's not worth risking your safety or those nice forks for this experiment, IMO.

I have no problem in leaving those forks where they are now. But I'd like to know why such repair/mod is not possible.
I.e., when you have a damaged fork steerer, say chewed threads, would you automatically scrap the forks or re-use on a smaller frame; or -according to their cost- one may replace the steerer only?

Probably I've put the things in the wrong way, too much information given may lead to a wrong idea of why this thread is up.
I should have just wrote "I've a set of spare forks which are a bit expensive, and would like to have the steerer replaced partially or entirely. Is it something can be done? What are the problems involved?"