atypical stuck seat post: Andrew Muzi help!

"DATAKOLL MARINE RESEARCH" wrote in message
...
On Saturday, June 25, 2016 at 8:08:43 AM UTC-4, AMuzi wrote:
On 6/24/2016 9:54 PM, John B. wrote:
On Thu, 23 Jun 2016 19:20:41 -0700 (PDT), LF wrote:

A friend's inherited bike (Specialized Sequoia) has a stuck seat post.
(Steel bike, aluminum seat post). Currently, the seat height is too
short for him. With the seat post clamp undone, I can rotate the post
left and right, using the saddle for leverage. I am not able to pull
the seat post out of the seat tube even a little bit (I marked it with
tape so I could see).

This is a fluted seat post, not the original for a Sequoia. My theory
is the seat post is slightly too fat for the seat tube, and the
original owner banged it in to its current position.

Lubrication helped. Ammonia did not seem to help.

I would like to fix this tomorrow, Friday, for a century ride this
week-end. (Cape Cod Getaway, MS fundraiser). My friend would like to
take it on this ride for sentimental reasons. I'll try putting the
bike upside down in a bench vice, clamping down on the seat post, and
using the frame for leverage.

I hope to avoid cutting it off, and then hack sawing internally
vertically. If I resort to that, are there now power tools to make it
easy?

Any advise will be appreciated.

Thanks,
Larry

Firstly cutting the seat post and trying to hack saw it lengthwise
down the seat tub is going to be a pretty tedious project even if you
are successful.

I once drilled out a seat post using a "drill" I made from a hole saw
carefully ground down the fit the seat tube. It took me about a week
to make the drill and remove the seat post :-)

I would recommend reading Sheldon Brown's recommendations for stuck
seat posts. http://www.sheldonbrown.com/stuck-seatposts.html

My suggestion for an aluminum seat post in a steel frame would be to
us drain cleaner (lye, caustic soda, sodium hydroxide). Disassemble
the bike. seal the seat tube/seat post joint and pour drain cleaner
through the bottom bracket into the seat post.

Caustic soda (lye) is a very strong alkali and will burn you if it
contacts your skin and reacts with aluminum to produce hydrogen gas so
appropriate safety measures should be taken.
There a number of youtube films on this.


Since it moves, you'll likely get it out whole.

First wash out the ammonia with hot water from both ends,
spray dry. An oxide reducer can help but time is your enemy.

Rinse with solvent to remove any oils etc, spray dry then
try a good penetrant such as PC Blaster or Delco Penetrant.
Warming it with a heatgun then allowing it to cool can get
more of the residual moisture out before you shoot the
penetrant.

Tap the post and seat tube smartly[1] while applying your
penetrant, again from both ends. Mount the top of the post
in a vise horizontally and rotate the frame, pulling from
the BB end as you turn it. Assistant can tap the post and
shoot your penetrant in as you do this. If the top breaks
away, insert a steel bar inside the post and grab the stump
again in your vise.

If it all goes awry you can either machine it out (tedious)
or melt it out (paint loss).

[1] large smooth faced tool on the paint. A smart tap is not
a bash. You want vibration to help the penetrant, not dents
in the frame.

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

heat gun better than torch

lubricant before pulling ? wishful thinking but why not..

well....twisting is not in odor nor adding a dissolving lubricant.

If you can't twist it - use a slide hammer.

Car thieves used to make them up from surprisingly basic materials with a
self tapping screw welded on the end for pulling IGN lock barrels.

You need a long thin bar and a heavy lump of steel with a hole to fit the
bar. Weld a nut on the end of the bar so the lump can't fly off and devise
some way of attaching the other end to the seat post.

If you can't twist it - use a slide hammer.


https://goo.gl/6dFNtq

weight lifting plates with 2" holes ....

Goo sends a page

https://www.google.com/imgres?imgurl...act=mrc&uact=8

On Saturday, June 25, 2016 at 6:27:40 PM UTC-4, DATAKOLL MARINE RESEARCH wrote:
If you can't twist it - use a slide hammer.


https://goo.gl/6dFNtq

weight lifting plates with 2" holes ....

Goo sends a page

https://www.google.com/imgres?imgurl...act=mrc&uact=8

https://www.google.com/#q=aluminium+corrosion+removal

my potion for seat posts...

aluminum anti-seize mixed with a dollop of boiled linseed oil, flooding the anti sieze mass.

mix, spread over seat post n insert.

fluids discussion

I've used vinegar for SS knife rust. Knife in jar filled with AAA vinegar..vingar turns rust black...black rubs out with a rough ball of aluminum foil scrubber.


http://www.practicalmachinist.com/vb...metals-219301/