Threaded to threadless ponder.

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mrjemm
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Threaded to threadless ponder.

Postby mrjemm » 29 Nov 2012, 10:05am

There are various references about the web on this matter, but not many recent ones that I can find that really help me.

I have got myself an old steel mtb frame with a 1" threaded set up. Really I would like to get this a bit more modern (or should I say, more suited to my abilities and taste?), and have it converted to threadless. I have seen that I can get a new steerer tube put on for a reasonable price, but I am unsure how simple the headset mounting will be. Looking at Sheldon's cribsheet- http://sheldonbrown.com/cribsheet-headsets.html it looks to me as if the headset should fit in, assuming "frame cup outside diameter" is the inner diameter of the headtube.

I was over the border in Yorkshire yesterday, and was hoping to have a chat with the folks in Ellis Briggs, where they list new fork column at £36. Daftly though, I didn't notice they're closed wednesdays. So I wonder if anyone could tell me if I am missing something- will this work? And does anyone know somewhere (preferably in or near N Lancs) that would do a good (and well priced) fork tube conversion?

...Now out to my shed to try to work out cable routing for another experiment I have on the go. Hopefully the radiator's killed the chill in there a bit. Look back in here when I come for a brew. Cheers, Jem.

Brucey
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Re: Threaded to threadless ponder.

Postby Brucey » 29 Nov 2012, 10:12am

should work fine. There are some DIY options too.

cheers
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breakwellmz
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Re: Threaded to threadless ponder.

Postby breakwellmz » 29 Nov 2012, 10:13am


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531colin
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Re: Threaded to threadless ponder.

Postby 531colin » 29 Nov 2012, 10:41am

If you want to use a threadless headset, then a quill stem adapter will not help you much....will it? :?

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breakwellmz
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Re: Threaded to threadless ponder.

Postby breakwellmz » 29 Nov 2012, 11:02am

No,quite right!

I`m obviously being REALLY stupid this morning :oops:

Surely the only reason you would WANT to use a threadless headset would because you have a threadless stem? :)

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horizon
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Re: Threaded to threadless ponder.

Postby horizon » 29 Nov 2012, 11:09am

When I looked at this, I too thought he meant that he just wanted the top end of a nice new looking threadless head - that's 2/9d and a few minutes work. But it seems mrjemm wants the whole works, though he doesn't say why. Am I confused too?

It's the order of words:
... have it converted ...
Let's just get Brexit done so that we can get on with the important job of re-joining the EU!

Brucey
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Re: Threaded to threadless ponder.

Postby Brucey » 29 Nov 2012, 11:19am

one DIY option is to chop the threaded section off the steerer, and then bond an A-head stem adaptor into the steerer, using a suitable epoxy resin. A long bolt to the crown as backup isn't a bad idea.

If you don't fancy this in the long term, it at least allows you to experiment at relatively lower cost.

Note that you need to be careful with butted steerers; you might cut off to much of the unbutted part, making insertion of enough of the adaptor impossible.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

stewartpratt
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Re: Threaded to threadless ponder.

Postby stewartpratt » 29 Nov 2012, 12:14pm

Wouldn't it be better to simply buy a new fork?

If the price of a new steerer is as low as £36 then I would think that must be for a cast-crown fork, whereas if you have an MTB it's likely to be a welded unicrown. Replacing the steerer on one of those will not be economically viable.

mrjemm
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Re: Threaded to threadless ponder.

Postby mrjemm » 29 Nov 2012, 12:31pm

I am not loaded, but I like to do things "properly" when I can, and simply don't like old style headsets, and want to "future-proof" the set-up (albeit with a 1" steerer, which is of course limiting my options).

I have pondered an adaptor as a stop-gap measure, or at worst, a final necessity if all else fails, but to me it is a fudge and not what I want (as opposed to need). After all, this is a (hopefully fun) project, not a means to an end.

New forks are likewise a possible end requirement, but I would prefer to get these forks set up as I like them, however what Stewart says does concern me a bit, as yes, they are welded unicrown. What may be feasible is a more professionally done version of Brucey's chop'n sleeve suggestion, i.e. Give to a pro who could chop and then weld (braze?) an extension on (with inner sleeve?). In my naivety, I cannot see this being a huge challenge to someone with those skills (ok, a daft redundant comment).

Anyway, thank you all for these suggestions and thoughts. I must now go get some cable outer after not measuring twice before cutting... Ooops.

stewartpratt
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Re: Threaded to threadless ponder.

Postby stewartpratt » 29 Nov 2012, 12:56pm

mrjemm wrote:What may be feasible is a more professionally done version of Brucey's chop'n sleeve suggestion


Quite possibly.

What fork is it, by the way? Something worth the hassle of converting it, presumably...?

Brucey
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Re: Threaded to threadless ponder.

Postby Brucey » 29 Nov 2012, 1:02pm

a correctly made adhesive bond, when loaded in shear, will have a strength of about one tonne per square inch. You can easily get many square inches in a steerer joint, with (say) a 3" overlap. Supposing that you are completly incompetent, and the bond (which would normally have a safety margin of between 10 and 100) fails; nothing can 'escape' if a long bolt/headlock is used; all that will happen is that you won't be able to put a large torque through the steering any more; not something most people do, anyway.

The arrangement I suggest is not highly loaded; it would probably work acceptably well with, say, wallpaper paste in the joint.... :roll:

There may well be plenty of other adhesively bonded joints on your bicycle; seat pin tops are often bonded into the tube, all kinds of parts often use adhesives to secure them, like bolts, bearings and so forth. Most tyres are effectively held together by adhesive bonding, too. Like most technology, it is just fine if it is used in the right way in the right place.

By contrast extending steerer tubes by brazing is no easier, and possibly no more likely to render a truly durable joint. Steerers are subject to fatigue loading, the joint will be made in a thin-walled part of the steerer, the cold work and temper in the steel will be lost by the brazing process (differently with different steels) and any developing cracks in service will be well hidden from view. This is a bad combination!

If you get what you suppose to be a 'professional' job done I would definitely use a long bolt with that, too. Note also that (unlike the bonded arrangment) if the joint cracks or fails, the parts won't be held in good alignment even with a long bolt.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

hexhome
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Re: Threaded to threadless ponder.

Postby hexhome » 29 Nov 2012, 3:37pm

mrjemm wrote: simply don't like old style headsets


But why? They have worked well for years, last much longer in my experience and are easy to adjust correctly. I'm all for modernising bikes when it makes sense, but this appears to be an unessential expense for no real gain. But then I've just changed an outboard bearing bottom bracket for a square taper one!

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531colin
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Re: Threaded to threadless ponder.

Postby 531colin » 29 Nov 2012, 4:02pm

Brucey wrote:one DIY option is to chop the threaded section off the steerer, and then bond an A-head stem adaptor into the steerer, using a suitable epoxy resin. A long bolt to the crown as backup isn't a bad idea. .................


But you will need to make up the diameter back to 1" for the headset?

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CREPELLO
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Re: Threaded to threadless ponder.

Postby CREPELLO » 29 Nov 2012, 4:37pm

531colin wrote:
Brucey wrote:one DIY option is to chop the threaded section off the steerer, and then bond an A-head stem adapter into the steerer, using a suitable epoxy resin. A long bolt to the crown as backup isn't a bad idea. .................


But you will need to make up the diameter back to 1" for the headset?

Not with a BBB adapter :wink:
http://www.wiggle.co.uk/bbb-bhp-2021-stem-extender/
You then use ahead spacers as usual, which I suspect will be a relief to mrjemm. Aesthetically, i would look like a normal ahead set up.

Incidentally, the threaded headset can be converted to an aheadset with a replacement top race cap. http://www.jejamescycles.co.uk/mpart-he ... d4675.html

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breakwellmz
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Re: Threaded to threadless ponder.

Postby breakwellmz » 29 Nov 2012, 4:47pm

Brucey wrote:a correctly made adhesive bond, when loaded in shear, will have a strength of about one tonne per square inch. You can easily get many square inches in a steerer joint, with (say) a 3" overlap. Supposing that you are completly incompetent, and the bond (which would normally have a safety margin of between 10 and 100) fails; nothing can 'escape' if a long bolt/headlock is used; all that will happen is that you won't be able to put a large torque through the steering any more; not something most people do, anyway.

The arrangement I suggest is not highly loaded; it would probably work acceptably well with, say, wallpaper paste in the joint.... :roll:

There may well be plenty of other adhesively bonded joints on your bicycle; seat pin tops are often bonded into the tube, all kinds of parts often use adhesives to secure them, like bolts, bearings and so forth. Most tyres are effectively held together by adhesive bonding, too. Like most technology, it is just fine if it is used in the right way in the right place.

By contrast extending steerer tubes by brazing is no easier, and possibly no more likely to render a truly durable joint. Steerers are subject to fatigue loading, the joint will be made in a thin-walled part of the steerer, the cold work and temper in the steel will be lost by the brazing process (differently with different steels) and any developing cracks in service will be well hidden from view. This is a bad combination!

If you get what you suppose to be a 'professional' job done I would definitely use a long bolt with that, too. Note also that (unlike the bonded arrangment) if the joint cracks or fails, the parts won't be held in good alignment even with a long bolt.

cheers


Hi.

`This is one i made earlier`
The fork originally had a 1 1/8" steerer which has been replaced by a length of 1" stainless tube.
This is`all mechanically`held together.The tube being an interference fit into the fork,pinned in place by a stainless M6 coachbolt,pressed in.

Cheers
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