Stuck seatpost - a new idea?

On 11/10/2014 8:32 AM, AMuzi wrote:


If you're going to attempt a mechanical removal at that level of
corrosion ( and I heartily encourage you especially since owner seems
not to have much experience in the area) you might cut the top of the
post and slip a steel bar inside so the post doesn't crush and tear when
you clamp and twist it.

Good idea, if it comes to that. This is another guy whose house lacks
the very useful boxes of metal stock that I keep around here. I guess I
can take along an assortment of steel bars and pipes, hoping for one
that fits.


In my experience the last infallible resort is that the aluminum post
melts well before any damage to the steel frame.

I saw that impressive photo on your website. But I'm sure he'd prefer
not having to repaint his frame. I sure hope things come out easier.

There are some cool YouTube videos showing people in haz-mat suits
dissolving seatposts via harsh chemicals. His daughter is a chemistry
student, so that could be educational. But that method seems to take
several hours.


--
- Frank Krygowski

In article ,
Frank Krygowski wrote:

On 11/9/2014 11:52 PM, James wrote:
On 10/11/14 13:13, Frank Krygowski wrote:
Stuck seatposts have been discussed here many times over the years.
Apparently, the most common situation is an aluminum post stuck in a
steel frame.

I've never had the problem, but a good friend of mine who lives over an
hour away has the problem now. He's not an expert on mechanical things.
(For example, after he sent me a photo of the seatpost/seat tube
juncture, I said "Well, your seatpost is aluminum..." and he replied
"How do you know that?") Penetrating oil and much tugging and twisting
on the saddle has done him no good.

Anyway, I pointed him to Sheldon Brown
http://sheldonbrown.com/stuck-seatposts.html
and I think he may now be trying to have some ammonia trickle into the
joint.

But I'll be visiting in a couple weeks, and I'm wondering if this has
been tried: Finding or boring a section of steel pipe with an ID just
larger than the seatpost diameter (27.2mm in his case), splitting it
longitudinally, re-assembling and very lightly clamping it around the
protruding seatpost, then using it as a support to pry, lever or jack
the saddle and seatpost upward. The pipe would transfer the compressive
reaction load to the top edge of the steel seat tube.

I imagine I'd need a steel plate under the saddle. I can conceive of an
arrangement of screw threads to do the lifting, using nuts welded to the
steel pipe so as to support the lower end of bolts. But again, I've got
no experience with this repair, so perhaps the force doesn't need to be
very great?

I'll be visiting only for a few hours, so I'll have just one chance to
help him out. Anybody know if this method has ever succeeded?



Seat posts are cheap. Why not cut the end off so that the steel tube
can slide over the seat post without needing to split it longitudinally,
which would weaken it I'm sure.

I'd then tap a thread inside the seat post, and with the tube slightly
longer than the seat post, and with a plate with a hole as a stiff
washer, try to pull the seat post out as you describe.

You're right, that would be easier, if he's willing to destroy his
seatpost.

Impact is the usual answer for frozen things like nuts and studs. How
about just taking the seat off and giving the top of the seat post a few
whacks with a hammer?

On Sunday, November 9, 2014 9:13:18 PM UTC-5, Frank Krygowski wrote:
Stuck seatposts have been discussed here many times over the years.
Apparently, the most common situation is an aluminum post stuck in a
steel frame.

I've never had the problem, but a good friend of mine who lives over an
hour away has the problem now. He's not an expert on mechanical things.
(For example, after he sent me a photo of the seatpost/seat tube
juncture, I said "Well, your seatpost is aluminum..." and he replied
"How do you know that?") Penetrating oil and much tugging and twisting
on the saddle has done him no good.

Anyway, I pointed him to Sheldon Brown
http://sheldonbrown.com/stuck-seatposts.html
and I think he may now be trying to have some ammonia trickle into the
joint.

But I'll be visiting in a couple weeks, and I'm wondering if this has
been tried: Finding or boring a section of steel pipe with an ID just
larger than the seatpost diameter (27.2mm in his case), splitting it
longitudinally, re-assembling and very lightly clamping it around the
protruding seatpost, then using it as a support to pry, lever or jack
the saddle and seatpost upward. The pipe would transfer the compressive
reaction load to the top edge of the steel seat tube.

I imagine I'd need a steel plate under the saddle. I can conceive of an
arrangement of screw threads to do the lifting, using nuts welded to the
steel pipe so as to support the lower end of bolts. But again, I've got
no experience with this repair, so perhaps the force doesn't need to be
very great?

I'll be visiting only for a few hours, so I'll have just one chance to
help him out. Anybody know if this method has ever succeeded?

--
- Frank Krygowski

I've got really stuck setposts out (destructively for the post though) by cuttin off tthe top of the post then rapidly cooling the interior of the post whilst simultaneously using a hot air gun to heat the steel frame in the area where the post is. The aluminium post cools and shrinks and the steel seat tube heats and expands. A helper to hold onto the wrench or whatever you use to turn the seatpost is a big help. Sometimes tapping the wrench as you work will cause the post to suddenly break loose.


Good luck.

I'd suggest taking out the bottom bracket and cranks. Then pouring a quart or so of penetrating oil down the seattube. Let it sit a week or a month. Then use a pipe wrench on the seatpost and/or hit the seatpost with a hammer. Let the oil have time to work.

Sir Ridesalot schreef op 10-11-2014 19:48:
On Sunday, November 9, 2014 9:13:18 PM UTC-5, Frank Krygowski wrote:
Stuck seatposts have been discussed here many times over the years.
Apparently, the most common situation is an aluminum post stuck in a
steel frame.

I've never had the problem, but a good friend of mine who lives over an
hour away has the problem now. He's not an expert on mechanical things.
(For example, after he sent me a photo of the seatpost/seat tube
juncture, I said "Well, your seatpost is aluminum..." and he replied
"How do you know that?") Penetrating oil and much tugging and twisting
on the saddle has done him no good.

Anyway, I pointed him to Sheldon Brown
http://sheldonbrown.com/stuck-seatposts.html
and I think he may now be trying to have some ammonia trickle into the
joint.

But I'll be visiting in a couple weeks, and I'm wondering if this has
been tried: Finding or boring a section of steel pipe with an ID just
larger than the seatpost diameter (27.2mm in his case), splitting it
longitudinally, re-assembling and very lightly clamping it around the
protruding seatpost, then using it as a support to pry, lever or jack
the saddle and seatpost upward. The pipe would transfer the compressive
reaction load to the top edge of the steel seat tube.

I imagine I'd need a steel plate under the saddle. I can conceive of an
arrangement of screw threads to do the lifting, using nuts welded to the
steel pipe so as to support the lower end of bolts. But again, I've got
no experience with this repair, so perhaps the force doesn't need to be
very great?

I'll be visiting only for a few hours, so I'll have just one chance to
help him out. Anybody know if this method has ever succeeded?

--
- Frank Krygowski

I've got really stuck setposts out (destructively for the post though) by cuttin off tthe top of the post then rapidly cooling the interior of the post whilst simultaneously using a hot air gun to heat the steel frame in the area where the post is. The aluminium post cools and shrinks and the steel seat tube heats and expands. A helper to hold onto the wrench or whatever you use to turn the seatpost is a big help. Sometimes tapping the wrench as you work will cause the post to suddenly break loose.


Good luck.


Lube the f*cking seatpost from time to time to avoid this kind off
situations. I spent four hours once to saw, file, pry out a stuck
seatpost of a friends bike. Recently I asked him if he lubed the new one
recently. 'yeah I have to do that..' Sigh.....

Lou

http://goo.gl/ebxMTC
http://goo.gl/GCz7nl

http://goo.gl/5GvYub

http://goo.gl/QKiChw


gee whiz damn shame awl doahn read my posts.

It's the surface area np...like red locktite on small bolts visavee red loctite on large bolts

I am at a loss for figuring reaction rates but will go with electons/weight nucleus and aluminum oxide forming next to instantly when Al is gouged fresh.
Guess is when 2 spaces, Fe and Al are open the al fills first and with more POW more pressure...then the AlOH reaction involves a trading of ions to corrode the Al...lets see back to Images...

Ugh nnnnnnnnnnnnnnnnnnnnnn

http://goo.gl/RJGWbs

On Sun, 09 Nov 2014 21:13:07 -0500, Frank Krygowski
wrote:

But I'll be visiting in a couple weeks, and I'm wondering if this has
been tried: Finding or boring a section of steel pipe with an ID just
larger than the seatpost diameter (27.2mm in his case), splitting it
longitudinally, re-assembling and very lightly clamping it around the
protruding seatpost, then using it as a support to pry, lever or jack
the saddle and seatpost upward. The pipe would transfer the compressive
reaction load to the top edge of the steel seat tube.

I don't think you can clamp down on the aluminum seat post with enough
pressure. If you try to pull or rotate the assembly by the clamp, I
think it will slip. If the seat post is fluted, you might get a
decent grip. Or, just drill a hole in the seat tube.

I imagine I'd need a steel plate under the saddle. I can conceive of an
arrangement of screw threads to do the lifting, using nuts welded to the
steel pipe so as to support the lower end of bolts. But again, I've got
no experience with this repair, so perhaps the force doesn't need to be
very great?

My limited experience with extracting seat posts suggests that the
extraction force is greater than what it takes to bend the frame.

I'll be visiting only for a few hours, so I'll have just one chance to
help him out. Anybody know if this method has ever succeeded?

No clue.

If you only have a few hours, turn the bike over and clamp the seat
post in a bench vice. Fill the seat tube with penetrating oil. Let
sit a while. Then rotate the frame using a 2x4 for leverage.
Hopefully, you won't bend the frame. Once it's broken free, try a
slide hammer pilot bearing puller to extract the seatpost. Something
like this but with longer teeth:
http://tetoolsusa.com/tools/images/2-1170.jpg
or something crude like this:
https://www.flickr.com/photos/singlespeedoutlaw/760980580/

Tools for seat post removal:
https://www.google.com/search?q=seat+post+removal+tool&tbm=isch

Good luck.

Frank: I have the ebay vehicle detector in hand. I made a loop and
found that it runs at about 60KHz. However, I've been sick and
overworked lately, and have little spare time. Sorry(tm).

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

try this one

http://goo.gl/CFQUwP

back to work

On 11/10/2014 1:50 PM, wrote:
-snip-

gee whiz damn shame awl doahn read my posts.

you may have poisoned the waters again with your comments to
Mr Cleary.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Monday, November 10, 2014 2:12:18 PM UTC-5, Lou Holtman wrote:
Sir Ridesalot schreef op 10-11-2014 19:48:
On Sunday, November 9, 2014 9:13:18 PM UTC-5, Frank Krygowski wrote:
Stuck seatposts have been discussed here many times over the years.
Apparently, the most common situation is an aluminum post stuck in a
steel frame.

I've never had the problem, but a good friend of mine who lives over an
hour away has the problem now. He's not an expert on mechanical things.
(For example, after he sent me a photo of the seatpost/seat tube
juncture, I said "Well, your seatpost is aluminum..." and he replied
"How do you know that?") Penetrating oil and much tugging and twisting
on the saddle has done him no good.

Anyway, I pointed him to Sheldon Brown
http://sheldonbrown.com/stuck-seatposts.html
and I think he may now be trying to have some ammonia trickle into the
joint.

But I'll be visiting in a couple weeks, and I'm wondering if this has
been tried: Finding or boring a section of steel pipe with an ID just
larger than the seatpost diameter (27.2mm in his case), splitting it
longitudinally, re-assembling and very lightly clamping it around the
protruding seatpost, then using it as a support to pry, lever or jack
the saddle and seatpost upward. The pipe would transfer the compressive
reaction load to the top edge of the steel seat tube.

I imagine I'd need a steel plate under the saddle. I can conceive of an
arrangement of screw threads to do the lifting, using nuts welded to the
steel pipe so as to support the lower end of bolts. But again, I've got
no experience with this repair, so perhaps the force doesn't need to be
very great?

I'll be visiting only for a few hours, so I'll have just one chance to
help him out. Anybody know if this method has ever succeeded?

--
- Frank Krygowski

I've got really stuck setposts out (destructively for the post though) by cuttin off tthe top of the post then rapidly cooling the interior of the post whilst simultaneously using a hot air gun to heat the steel frame in the area where the post is. The aluminium post cools and shrinks and the steel seat tube heats and expands. A helper to hold onto the wrench or whatever you use to turn the seatpost is a big help. Sometimes tapping the wrench as you work will cause the post to suddenly break loose.


Good luck.


Lube the f*cking seatpost from time to time to avoid this kind off
situations. I spent four hours once to saw, file, pry out a stuck
seatpost of a friends bike. Recently I asked him if he lubed the new one
recently. 'yeah I have to do that..' Sigh.....

Lou

Kind of hard to lube someone's stuck seatpost if that seatpost won't move. I lubricate mine once a year when I do my annual checkup.

Cheers