Crank thread stripped: what now?

[[email protected]]

Hello all,
the crank-extractor thread on my left crank (shimano deore aluminium
square taper) is completely stripped.
I have already extracted the crank, but I would like to use it again
and therefore make it "easily" extractable.
Is there any way to cheaply repair it?
What if I buy a self-extracting bolt and sort of "weld" it in place
(is loctite strong enough? the thread is completely gone)

Thanks,
Federico

 

[Nate Knutson]

On Sep 19, 2:14 pm, "[email protected]" <[email protected]> wrote:
> Hello all,
> the crank-extractor thread on my left crank (shimano deore aluminium
> square taper) is completely stripped.
> I have already extracted the crank, but I would like to use it again
> and therefore make it "easily" extractable.
> Is there any way to cheaply repair it?
> What if I buy a self-extracting bolt and sort of "weld" it in place
> (is loctite strong enough? the thread is completely gone)
>
> Thanks,
> Federico

probably the most practical thing is a new crank.
there's the stein repair system (http://jastein.com/
Tools_for_Cranks.htm) and i think that a system involving cutting
oversize threads and a special puller also exists. certain better
shops will have one of these systems, but a left crank will be cheaper
than having a shop do it.
using epoxy or something with a self extractor would probably work,
presuming you could get the bonded part to be in the right alignment
when it was all set. sounds tricky.

 

[A Muzi]

[email protected] wrote:
> Hello all,
> the crank-extractor thread on my left crank (shimano deore aluminium
> square taper) is completely stripped.
> I have already extracted the crank, but I would like to use it again
> and therefore make it "easily" extractable.
> Is there any way to cheaply repair it?
> What if I buy a self-extracting bolt and sort of "weld" it in place
> (is loctite strong enough? the thread is completely gone)

Sure, the VAR 1010 system is a piloted tap for a larger coarser thread
with a steel insert for the remover, get it machined at any competent LBS.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[John Thompson]

On 2007-09-19, [email protected] <[email protected]> wrote:

> the crank-extractor thread on my left crank (shimano deore aluminium
> square taper) is completely stripped.
> I have already extracted the crank, but I would like to use it again
> and therefore make it "easily" extractable.
> Is there any way to cheaply repair it?
> What if I buy a self-extracting bolt and sort of "weld" it in place
> (is loctite strong enough? the thread is completely gone)

VAR Tools makes a kit for retapping extractor threads to a larger size.
It's not cheap if you buy it for a one-off job, but if your LBS has one
already it might not be to expensive to have it done. You will need a
new oversize extractor (also avqailable from VAR) to remove the cranks
after they are retapped.

--

John ([email protected])

 

[datakoll]

call around or better ride around, bring a wad of ones, hang out and
ask for the used or left-over left hand crank bin. buy 3.
don't screw around with loctite or epoxy, you'll screw yourself good
when it fsils. anyways, loctite works on ferrous metals at least one
side so if the assembly's all AL you need to add Fe dust.

 

I use a piloted bottoming tap that replaces the original 22mm threads
with 23mm threads, the "other" size on double-sided pullers that fit
either standard or TA cranks. Expensive tool, not worth it to save one
crank, but if a shop near you has one, rethreading is simple and does
not take much time.

--
[email protected] is Joshua Putnam
<http://www.phred.org/~josh/>
Braze your own bicycle frames. See
<http://www.phred.org/~josh/build/build.html>

 

[Mike Jacoubowsky]

>> Hello all,
>> the crank-extractor thread on my left crank (shimano deore aluminium
>> square taper) is completely stripped.
>> I have already extracted the crank, but I would like to use it again
>> and therefore make it "easily" extractable.
>> Is there any way to cheaply repair it?
>> What if I buy a self-extracting bolt and sort of "weld" it in place
>> (is loctite strong enough? the thread is completely gone)
>
> Sure, the VAR 1010 system is a piloted tap for a larger coarser thread
> with a steel insert for the remover, get it machined at any competent LBS.

Yes, but it's a *left* crank arm, which is relatively cheap, and since he'd
like to make it "easily" extractable again, I think having to use a special
not-easy-to-find extractor in the future defeats the purpose. Or to put it
another way, by the time he pays for having the crank re-tapped *and* the
new tool he'll need to remove it, he'll have spent more than he would have
for a new crank arm.

I think the VAR 1010 solution makes more sense when trying to recover either
a very expensive or difficult-to-replace crank arm.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"A Muzi" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote:
>> Hello all,
>> the crank-extractor thread on my left crank (shimano deore aluminium
>> square taper) is completely stripped.
>> I have already extracted the crank, but I would like to use it again
>> and therefore make it "easily" extractable.
>> Is there any way to cheaply repair it?
>> What if I buy a self-extracting bolt and sort of "weld" it in place
>> (is loctite strong enough? the thread is completely gone)
>
> Sure, the VAR 1010 system is a piloted tap for a larger coarser thread
> with a steel insert for the remover, get it machined at any competent LBS.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971

 

[David L. Johnson]

[email protected] wrote:
> Hello all,
> the crank-extractor thread on my left crank (shimano deore aluminium
> square taper) is completely stripped.
> I have already extracted the crank, but I would like to use it again
> and therefore make it "easily" extractable.
> Is there any way to cheaply repair it?
> What if I buy a self-extracting bolt and sort of "weld" it in place
> (is loctite strong enough? the thread is completely gone)

If you really don't want to buy a new crank, find a gear puller (this is
used in auto repair to pull pulleys and the like off of their shafts)
that will fit over the crank. This may damage the crank, but you've
already done that.

--

David L. Johnson

Accept risk. Accept responsibility. Put a lawyer out of business.

 

[Mike Jacoubowsky]

>> Hello all,
>> the crank-extractor thread on my left crank (shimano deore aluminium
>> square taper) is completely stripped.
>> I have already extracted the crank, but I would like to use it again
>> and therefore make it "easily" extractable.
>> Is there any way to cheaply repair it?
>> What if I buy a self-extracting bolt and sort of "weld" it in place
>> (is loctite strong enough? the thread is completely gone)
>
> If you really don't want to buy a new crank, find a gear puller (this is
> used in auto repair to pull pulleys and the like off of their shafts) that
> will fit over the crank. This may damage the crank, but you've already
> done that.

Have you had much success with gear pullers? We've tried them in the past
and rarely found them to be of much use. Could be that we didn't have the
right-size gear puller, or wrong technique, but I'd be interested in hearing
from people who have made good use of them to remove cranks.

Thanks-

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"David L. Johnson" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote:
>> Hello all,
>> the crank-extractor thread on my left crank (shimano deore aluminium
>> square taper) is completely stripped.
>> I have already extracted the crank, but I would like to use it again
>> and therefore make it "easily" extractable.
>> Is there any way to cheaply repair it?
>> What if I buy a self-extracting bolt and sort of "weld" it in place
>> (is loctite strong enough? the thread is completely gone)
>
> If you really don't want to buy a new crank, find a gear puller (this is
> used in auto repair to pull pulleys and the like off of their shafts) that
> will fit over the crank. This may damage the crank, but you've already
> done that.
>
> --
>
> David L. Johnson
>
> Accept risk. Accept responsibility. Put a lawyer out of business.

 

[sergio]

On Sep 20, 7:39 am, "Mike Jacoubowsky" <[email protected]>

> Have you had much success with gear pullers? We've tried them in the past
> and rarely found them to be of much use. Could be that we didn't have the
> right-size gear puller, or wrong technique, but I'd be interested in hearing
> from people who have made good use of them to remove cranks.

Not me, Mike. Sorry for disappointing you.
There was simply not enough room for the jaws.

On the other hand I do know that a couple of hard-wood wedges hammered
in place make an excellent puller, yet better if one has heated up a
bit the crank head.

Plus, here in Pisa I have very good connections and I know a competent
machine shop that would implant the elicoil for little money. They
have done it to a stripped 3ttt handlebar stem that I brought in,
recently.
One reservation I would make, however. It might not be easy to bore
correctly tp prepare for the tap [Andrew, please, put it into English
101].

So, Federico, do not dispair.
Call again next time you are in the neighborhood.

Sergio
Pisa

 

[Nate Knutson]

On Sep 19, 10:15 pm, "Mike Jacoubowsky" <[email protected]> wrote:
> >> Hello all,
> >> the crank-extractor thread on my left crank (shimano deore aluminium
> >> square taper) is completely stripped.
> >> I have already extracted the crank, but I would like to use it again
> >> and therefore make it "easily" extractable.
> >> Is there any way to cheaply repair it?
> >> What if I buy a self-extracting bolt and sort of "weld" it in place
> >> (is loctite strong enough? the thread is completely gone)
>
> > Sure, the VAR 1010 system is a piloted tap for a larger coarser thread
> > with a steel insert for the remover, get it machined at any competent LBS.
>
> Yes, but it's a *left* crank arm, which is relatively cheap, and since he'd
> like to make it "easily" extractable again, I think having to use a special
> not-easy-to-find extractor in the future defeats the purpose. Or to put it
> another way, by the time he pays for having the crank re-tapped *and* the
> new tool he'll need to remove it, he'll have spent more than he would have
> for a new crank arm..

Just checked and actually, the VAR system puts an oversized
proprietary self-extractor.on the crank. The kit comes with a seperate
crank puller for the shop.

What's the point, compared to the Stein?

 

[dabac]

Have you had much success with gear pullers?

Me neither. Main culprit I believe is that (LH) cranks quite often are sort of rounded/stepped on the inside, which makes it hard to get the extractor to stay put. And once it starts slipping there's not much to be done.
I have had some success with RH(4-arm) cranks though, particularly together with fairly short reach extractors.

 

[[email protected]]

On Sep 19, 4:14 pm, "[email protected]" <[email protected]> wrote:
> Hello all,
> the crank-extractor thread on my left crank (shimano deore aluminium
> square taper) is completely stripped.
> I have already extracted the crank, but I would like to use it again
> and therefore make it "easily" extractable.
> Is there any way to cheaply repair it?
> What if I buy a self-extracting bolt and sort of "weld" it in place
> (is loctite strong enough? the thread is completely gone)
>
> Thanks,
> Federico

Are you in Italy?

http://cgi.ebay.com/NEW-Shimano-Deo...ryZ56193QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

TIny: http://tinyurl.com/2xepz3

(left Deorearm, USA seller, "service to Europe")

Thinking along the time-money-less-PITA continuum: replace at least
that side, or maybe the whole crank.

Chainrings worn or damaged? Any gouges or heavy shoe wear on the right
side crank which could lead to breakage?

With some careful shopping you might be able to go all new (incl BB?)
for a good price, not all that much more than a fix or replacement
left crank arm, and go from there. --D-y

 

[Clive George]

"Mike Jacoubowsky" <[email protected]> wrote in message
news:[email protected]...
>>> Hello all,
>>> the crank-extractor thread on my left crank (shimano deore aluminium
>>> square taper) is completely stripped.
>>> I have already extracted the crank, but I would like to use it again
>>> and therefore make it "easily" extractable.
>>> Is there any way to cheaply repair it?
>>> What if I buy a self-extracting bolt and sort of "weld" it in place
>>> (is loctite strong enough? the thread is completely gone)
>>
>> If you really don't want to buy a new crank, find a gear puller (this is
>> used in auto repair to pull pulleys and the like off of their shafts)
>> that will fit over the crank. This may damage the crank, but you've
>> already done that.
>
> Have you had much success with gear pullers? We've tried them in the past
> and rarely found them to be of much use. Could be that we didn't have the
> right-size gear puller, or wrong technique, but I'd be interested in
> hearing from people who have made good use of them to remove cranks.

I made a puller for our tandem cranks (at least one of which has knackered
threads, and being a tandem crank in an odd length is very hard to replace).

It works well enough. I used mild steel strip, about 25mm x 3 or 4mm and
some 8mm threaded rod + nuts. The strip was of course too weak, so one side
got backed up with an old LH crank to provide ridigity.

Took a lot more force than I expected (hence the bent bits of metal). I also
needed to put a bit of metal over the thread in the BB to push against.

cheers,
clive

 

[D'ohBoy]

> On Sep 20, 7:39 am, "Mike Jacoubowsky" <[email protected]>
>
> > Have you had much success with gear pullers? We've tried them in the past
> > and rarely found them to be of much use. Could be that we didn't have the
> > right-size gear puller, or wrong technique, but I'd be interested in hearing
> > from people who have made good use of them to remove cranks.
>
I used them successfully in the past many times when I was too lazy to
purchase a real crank extractor. Room mate liked to work on his VW
Bus and had one...

Requires a bit of a gap between the crank and the bb shell but many
older cranks had this.

D'ohBoy

 

[Paul Kopit]

On Thu, 20 Sep 2007 01:22:50 -0400, "David L. Johnson"
<[email protected]> wrote:

>If you really don't want to buy a new crank, find a gear puller (this is
>used in auto repair to pull pulleys and the like off of their shafts)
>that will fit over the crank. This may damage the crank, but you've
>already done that.

I borrowed a fork shaped, tapered, thing from a Auto Zone for free. I
banged it in and the crank came off

 

[Mike Jacoubowsky]

>> Yes, but it's a *left* crank arm, which is relatively cheap, and since
>> he'd
>> like to make it "easily" extractable again, I think having to use a
>> special
>> not-easy-to-find extractor in the future defeats the purpose. Or to put
>> it
>> another way, by the time he pays for having the crank re-tapped *and* the
>> new tool he'll need to remove it, he'll have spent more than he would
>> have
>> for a new crank arm..
>
> Just checked and actually, the VAR system puts an oversized
> proprietary self-extractor.on the crank. The kit comes with a seperate
> crank puller for the shop.

My bad; I didn't realize it included a self-extractor.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"Nate Knutson" <[email protected]> wrote in message
news:[email protected]...
> On Sep 19, 10:15 pm, "Mike Jacoubowsky" <[email protected]> wrote:
>> >> Hello all,
>> >> the crank-extractor thread on my left crank (shimano deore aluminium
>> >> square taper) is completely stripped.
>> >> I have already extracted the crank, but I would like to use it again
>> >> and therefore make it "easily" extractable.
>> >> Is there any way to cheaply repair it?
>> >> What if I buy a self-extracting bolt and sort of "weld" it in place
>> >> (is loctite strong enough? the thread is completely gone)
>>
>> > Sure, the VAR 1010 system is a piloted tap for a larger coarser thread
>> > with a steel insert for the remover, get it machined at any competent
>> > LBS.
>>
>> Yes, but it's a *left* crank arm, which is relatively cheap, and since
>> he'd
>> like to make it "easily" extractable again, I think having to use a
>> special
>> not-easy-to-find extractor in the future defeats the purpose. Or to put
>> it
>> another way, by the time he pays for having the crank re-tapped *and* the
>> new tool he'll need to remove it, he'll have spent more than he would
>> have
>> for a new crank arm..
>
> Just checked and actually, the VAR system puts an oversized
> proprietary self-extractor.on the crank. The kit comes with a seperate
> crank puller for the shop.
>
> What's the point, compared to the Stein?
>

 

[A Muzi]

>> [email protected] wrote:
>>> the crank-extractor thread on my left crank (shimano deore aluminium
>>> square taper) is completely stripped.
>>> I have already extracted the crank, but I would like to use it again
>>> and therefore make it "easily" extractable.
>>> Is there any way to cheaply repair it?
>>> What if I buy a self-extracting bolt and sort of "weld" it in place
>>> (is loctite strong enough? the thread is completely gone)

"A Muzi" <[email protected]> wrote
>> Sure, the VAR 1010 system is a piloted tap for a larger coarser thread
>> with a steel insert for the remover, get it machined at any competent LBS.

Mike Jacoubowsky wrote:
> Yes, but it's a *left* crank arm, which is relatively cheap, and since he'd
> like to make it "easily" extractable again, I think having to use a special
> not-easy-to-find extractor in the future defeats the purpose. Or to put it
> another way, by the time he pays for having the crank re-tapped *and* the
> new tool he'll need to remove it, he'll have spent more than he would have
> for a new crank arm.
> I think the VAR 1010 solution makes more sense when trying to recover either
> a very expensive or difficult-to-replace crank arm.

Mikes' right.
I get a "D" in reading for comprehension today.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[!Jones]

On Wed, 19 Sep 2007 14:14:58 -0700, in rec.bicycles.tech
"[email protected]" <[email protected]> wrote:

>Hello all,
>the crank-extractor thread on my left crank (shimano deore aluminium
>square taper) is completely stripped.
>I have already extracted the crank, but I would like to use it again
>and therefore make it "easily" extractable.
>Is there any way to cheaply repair it?
>What if I buy a self-extracting bolt and sort of "weld" it in place
>(is loctite strong enough? the thread is completely gone)
>
>Thanks,
>Federico

eBay is your friend!

It's possible to bore it larger and rethread it, but that would cost
more than replacing it. You could also visit your auto tool shop and
look for a 2-arm "gear puller" that would fit. There, again, is
practically the cost of a crank.

I've been shopping for Cook Brothers cranks on eBay and I have seen at
least two single cranks for sale in as many weeks, so I know they
*can* be found.

WHOA!!! CHECK THIS OUT!!!

I popped over and looked... here's a left Deore crank:
http://cgi.ebay.com/NEW-Shimano-Deo...ryZ56193QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

You can't fix it any cheaper. If you don't like that one, just keep
your eyes open.

Jones

 

[!Jones]

On Wed, 19 Sep 2007 22:15:01 -0700, in rec.bicycles.tech "Mike
Jacoubowsky" <[email protected]> wrote:

>Yes, but it's a *left* crank arm, which is relatively cheap...

Left Xor right sell on eBay for about the same price. It's like
buying half a dog at the pet store... it really dosen't matter much
which half you buy; if they've only got half of it, then it's of
little use to most people. Ought to be $20 to $25 by the time you
ship it and you won't be able to repair it for that.

Jones