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PostPosted: Thu Aug 21, 2014 6:06 pm 
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timid kitty
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I am going to do something that everyone says you should not

any advice on neat ways to extend a steerer tube gratefully accepted

I will stick up a few picctures of the hack/injuries sustained after failure in due course..


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PostPosted: Thu Aug 21, 2014 6:19 pm 
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big hucker
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How short are we talking about?

Steerer material?

What type of bike?

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PostPosted: Thu Aug 21, 2014 6:52 pm 
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timid kitty
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well I have 2 that are a bit short,

1 of them is only a few mm short of the top, the stem does not grip it and it closes till the clamp touches if torqued up
I am thinking of a wide walled tube with OD of the steerer macined down so it is a push fit into the steerer (15mm?) and about 10mm over the top so I can get 1 small spacer on top of the stem.

for the other it needs about 20mm, I'm thinking of chopping it in the middle and doing a similar thing but obviously double ended with adhesive and a few steel pins to hold it together.

alu steerer tubes in revs and setor, Trail bike


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PostPosted: Fri Aug 22, 2014 9:12 am 
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bad kitty!
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Adhesive, yay! Steel pins, booooh!
Hysol 9466 yay! Random epoxy that says "super" on the tin, nay!


Magura :)

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PostPosted: Fri Aug 22, 2014 9:43 am 
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timid kitty
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Hysol 9466 :) thanks

Should l be putting small grooves into the sleeve for the adhesive?

Steel pins as a backup in case of adhesive failure not a good idea?

Any tips for prep on the alloy before gluing together, I read that etch primers can actually leave a residue that weakens the bond and fresh clean alloy is best?


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PostPosted: Fri Aug 22, 2014 2:19 pm 
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bad kitty!
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No pins, as if the bond fails, the pins will just make matters worse.
Sand the parts, make sure you have plenty of bonding surface, make room for a 0.5mm layer of adhesive, clean with isopropyl alcohol, cure at room temp.


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PostPosted: Fri Aug 22, 2014 2:40 pm 
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big hucker
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^^ Awesome.

I demand photos of the process and end result! :)

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PostPosted: Fri Aug 22, 2014 3:04 pm 
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pussy
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Interesting. I would not ride that without a dependable headlock.


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PostPosted: Fri Aug 22, 2014 3:42 pm 
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bad kitty!
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In that case you're in trouble, cause the steerer/crown interface is weaker. ;)


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PostPosted: Fri Aug 22, 2014 4:08 pm 
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timid kitty
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I thought the same thing, its just a friction fit I think? cue creaky fork noises :)

You dont think that the pins might be a lifsaver just in case something went wrong with the superexpoxypro.
I' cant see how would pins make matters worse, would it somehow compromise the strength of the bond?

If they held on long enough to let you stop rather than just separate without warning for example.


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PostPosted: Fri Aug 22, 2014 4:24 pm 
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bad kitty!
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The pins would compromise the strength of the tube, and serve no purpose.
Drilling holes in my steerer?,
Naah, I think I'll pass.

If you have like 50mm of overlap, you'll have like twice the strength of the crown/steerer interface.


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PostPosted: Fri Aug 22, 2014 5:22 pm 
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timid kitty
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thats very useful thanks!


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PostPosted: Tue Sep 02, 2014 8:35 pm 
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timid kitty
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update on progress

here is the short steerer with the stem fitted, it will tighten and not slip but the top clamp will close fully.. not nice

Image

adaptor/extender

Image

Image

Image

I dont really like it, going to make the hole much bigger

I think the part should be thin walled so it deforms into a slight oval shape when clamped to stop any rotation...

is that how it is made to work? or is it supposed to remain round when clamped and rely on friction to stop it slipping?


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PostPosted: Fri Oct 03, 2014 9:38 am 
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timid kitty
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machined a hollow in the top of the adaptor to allow the topcap to seat on the spacer/stem properly, has been doing its job with no creaks or stem slippage.

now for the other one...


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PostPosted: Fri Oct 03, 2014 9:47 am 
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bad kitty!
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It's supposed to rely on friction.
As soon as it gets out of round, I think you'll see all kinds of issues.

Nice job BTW.
Time to break out the adhesive!

Magura :)

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PostPosted: Sat Oct 04, 2014 12:19 pm 
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timid kitty
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Yes thanks, I was being dumb...again! :doh:

all better now

Image

Image

phase 2: time to glue some random tools onto the bench..


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PostPosted: Mon Oct 06, 2014 11:30 am 
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bad kitty!
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:D

Magura :)

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