Stuck seatpost - a new idea?

On Monday, November 10, 2014 3:25:09 PM UTC-5, AMuzi wrote:
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

WINTER COMES OVER THE HILL

THE COLDNESS DRIVES HUMOR INTO THE TILL

SUMMER'S HEAT

WINTER'S BITTER CHILL

THE CONTRADICTIONS OF HUMOR SHRED IN THE MILL

REALITY SUFFERS BY HEARTH'S BLAZING LIGHT

LET US LAUGH

WHEN MACHINISTS SHRED

POSTS IN THE NIGHT

On 11/10/2014 2:50 PM, wrote:


gee whiz damn shame awl doahn read my posts.

Well, sometimes we try...


--
- Frank Krygowski

On 11/10/2014 2:55 PM, Jeff Liebermann wrote:
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 may not have described my plan clearly enough. The split steel pipe
is not intended to clamp the seatpost. Quite the opposite; it needs to
allow the seatpost to slide axially through it.

Ideally, radial forces on the seatpost would be negligible, and present
at all only to keep the pipe concentric with the seatpost. Major forces
would be axial to the post: tensile on the post, with a reactive
compressive force on the steel tube. The steel tube and its attached
hardware would be pushing down on the top edge of the seat cluster (i.e.
the bike frame) and simultaneously pushing up on the saddle and
seatpost, possibly via a simple screw mechanism.


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).

No worries. Take your time, and thanks.


--
- Frank Krygowski

yeah my cars all had/have drum brakes tho I surfed into a packaged front end wit discs for the 544. So, with the ther stuff going on I went thru the maintenance routine on my van getting into disc brakes.

I'm impressed. The fronts went OK without new pads but I canna get new pads onto the rears: too much grease, lack of jiggle jiggle alignment pins going going in, damage , maybe leave pins loose to turn ? I dunno. Very little info there. The Ford forum threw me out....

However, there is maintenance happening.

See the bike. See the seat post ? What does it do? like a children's book to paraphrase Lou.

But wait. Let me compare thee to a summer's day....or a horses ass...or a rose would smell as sweet.....

We read posters claiming mechanical knowledge ripping past my pithy...harharhar pithy getit pithy...ok...observation that you can yammer all day about this solution or that but expletive deleted WTF are you pouring it on ? a small extremely narrow ring of crystalline exudation from corrosion that's pressuring the two walls of post and tube.

n these dullards with whom you deign conversation believe theirsolution is gonna chew thru the structure for ... ? and pop out comes the post.

hey gimme a break wudja ?

so how do these homebrew LED setups compare to cateye ?

izzit tru cateye puts out twice the lumens at 3x the cost ?

what I was getting at atomically ...not knowing what actually just throwing the idea out...maybe a metallurgist would come by..is FeO kinda lays flat taking a fairly long time to seriously jam the works. But Al-FE plus water and oxygen may not lay flat but develop a cube pshing against the wall in a faster reaction. As the last cube forms up n the last not quite enough space with two more wanna be cubes behind....thiss mooore than FeO but I doahno of this hypothesis is accurat

On Mon, 10 Nov 2014 15:53:03 +0000 (UTC), Doc O'Leary
wrote:

For your reference, records indicate that
John B. Slocomb wrote:

From the remains it
was apparent that the tube had essentially bonded to the steel seat
tube.

I wonder by what process. What we really need is a material scientist
who can say what is actually happening so that we can devise a proper
solution.

I tried: adapting an impact wrench to the seat tube, a rivet gun
applied to drive the post into the frame - thinking it would "break
the bond" so to speak, and finally a 24 inch pipe wrench on the post,
which after all the other tortures finally twisted the post off.

Not yet mentioned: heat and/or chill the frame so that there is a
significant difference in the thermal expansion of the two metals.

Yes there is. Aluminum seat posts expand more than steel seat tubes
:-)
--
Cheers,

John B.

On Monday, November 10, 2014 7:39:38 PM UTC-5, John B. Slocomb wrote:
On Mon, 10 Nov 2014 15:53:03 +0000 (UTC), Doc O'Leary
wrote:

For your reference, records indicate that
John B. Slocomb wrote:

From the remains it
was apparent that the tube had essentially bonded to the steel seat
tube.

I wonder by what process. What we really need is a material scientist
who can say what is actually happening so that we can devise a proper
solution.

I tried: adapting an impact wrench to the seat tube, a rivet gun
applied to drive the post into the frame - thinking it would "break
the bond" so to speak, and finally a 24 inch pipe wrench on the post,
which after all the other tortures finally twisted the post off.

Not yet mentioned: heat and/or chill the frame so that there is a
significant difference in the thermal expansion of the two metals.

Yes there is. Aluminum seat posts expand more than steel seat tubes
:-)
--
Cheers,

John B.

FFFFFFFFFFFFFFFFF

and with extensive corrosion, ion loss to the steel, tubing expands at a faster rate due to less internal cohesion !

On Mon, 10 Nov 2014 18:30:23 -0500, Frank Krygowski
wrote:

I may not have described my plan clearly enough. The split steel pipe
is not intended to clamp the seatpost. Quite the opposite; it needs to
allow the seatpost to slide axially through it.

Oh. I assumed a different mechanism.

Ideally, radial forces on the seatpost would be negligible, and present
at all only to keep the pipe concentric with the seatpost. Major forces
would be axial to the post: tensile on the post, with a reactive
compressive force on the steel tube. The steel tube and its attached
hardware would be pushing down on the top edge of the seat cluster (i.e.
the bike frame) and simultaneously pushing up on the saddle and
seatpost, possibly via a simple screw mechanism.

Won't work. You're pushing against the edge of the top tube with
whatever clamping contrivance you're fabricating. It's not strong
enough.

I had the same idea at one point and did roughly the same thing. I
fashioned a split length of steel tubing, that matched the contour of
the end of the top tube as best I could with a pneumatic hand grinder.
I had two hose clamps around the steel tubing, as close to the top
tube as possible. When I began applying pressure to the seat post
using a screw jack with a toggle link on the end, I watched the top
tube slowly begin to peel outward and mushroom. I stopped before I
destroyed the top tube. The problem is that the top tube is just not
thick enough to withstand the axial pressure without bending sideways.
The top tube edge is also slightly rounded, making it easier to peel.
I did no better when I ground a step on the inside edge of the split
steel tube, which bent the seat tube inward, causing it to clamp and
lock the seat tube. Not recommended.

I also ruined another frame with a similar non-functional method. I
attached a 1/4" steel plate to the seat post saddle screw using the
stock M8(?) bolt. I then stuffed jack screws on both sides of the
seat post and secured them to the top tube and to a plate attached
over the rear brake bosses. The seat post didn't move, but I did
manage to ding the top tube and partly shear off both brake bosses.
Not recommended.



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

On Mon, 10 Nov 2014 20:06:32 -0800, Jeff Liebermann
wrote:
(...)

On my way home, I thought of yet another way to unstick the seat post.
I used this method to extract swollen leaky D cell batteries from
aluminum Maglite flashlights, so I suspect it might work with a stuck
seat post.

You need an oscillating (20 KHz) multi-malfunction power tool, usually
used to scrape off paint and gouge into everything it touches:
http://www.harborfreight.com/oscillating-multifunction-power-tool-68861-8493.html
http://www.harborfreight.com/variable-speed-multifunction-power-tool-67537.html
Also get a replacement blade:
http://www.harborfreight.com/1-38-in-HCS-Multi-Tool-Plunge-Blade-61816.html
Find an old tape measure blade, and break off a 1ft section. The arc
of the tape measure blade will not match that of the seat post, but it
will bend to fit. Somehow, attach the tape blade to the vibrating
blade surface. I used epoxy, but that didn't last. Slip the tape
measure blade between the seat post and the seat tube and fire up the
oscillating power tool. The tape measure blade should be thin enough
to fit into the gap, and push the rust and oxide crud out of the way.

Disclaimer: I haven't tried this yet (except on a flashlight).


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

On Tuesday, November 11, 2014 12:46:14 AM UTC-5, Jeff Liebermann wrote:
On Mon, 10 Nov 2014 20:06:32 -0800, Jeff Liebermann
wrote:
(...)

On my way home, I thought of yet another way to unstick the seat post.
I used this method to extract swollen leaky D cell batteries from
aluminum Maglite flashlights, so I suspect it might work with a stuck
seat post.

You need an oscillating (20 KHz) multi-malfunction power tool, usually
used to scrape off paint and gouge into everything it touches:
http://www.harborfreight.com/oscillating-multifunction-power-tool-68861-8493.html
http://www.harborfreight.com/variable-speed-multifunction-power-tool-67537.html
Also get a replacement blade:
http://www.harborfreight.com/1-38-in-HCS-Multi-Tool-Plunge-Blade-61816.html
Find an old tape measure blade, and break off a 1ft section. The arc
of the tape measure blade will not match that of the seat post, but it
will bend to fit. Somehow, attach the tape blade to the vibrating
blade surface. I used epoxy, but that didn't last. Slip the tape
measure blade between the seat post and the seat tube and fire up the
oscillating power tool. The tape measure blade should be thin enough
to fit into the gap, and push the rust and oxide crud out of the way.

Disclaimer: I haven't tried this yet (except on a flashlight).


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

If you could get something as thick as a taoe measure blade between the seatpost and the seat tube then the seat post wouldn't br dtuck in the first place. You'd also be able to get a lubricant in there. If a post is really stuck there often isn't even enough room for the lubricant to even work its way along the entire length of the post inside the frame which is why the lubricant/penetrating oil idea often doesn't work either. I wonder if strngly vibrating the frame/seat post are for a while would loosen it a bit.

Ride the bike with the seat binder bolt out until tthe post moves then apply oil to lube tthe interface and then remove the post?

Cheers

On Monday, November 10, 2014 9:46:14 PM UTC-8, Jeff Liebermann wrote:
On Mon, 10 Nov 2014 20:06:32 -0800, Jeff Liebermann
wrote:
(...)

On my way home, I thought of yet another way to unstick the seat post.
I used this method to extract swollen leaky D cell batteries from
aluminum Maglite flashlights, so I suspect it might work with a stuck
seat post.

You need an oscillating (20 KHz) multi-malfunction power tool, usually
used to scrape off paint and gouge into everything it touches:
http://www.harborfreight.com/oscillating-multifunction-power-tool-68861-8493.html
http://www.harborfreight.com/variable-speed-multifunction-power-tool-67537.html
Also get a replacement blade:
http://www.harborfreight.com/1-38-in-HCS-Multi-Tool-Plunge-Blade-61816.html
Find an old tape measure blade, and break off a 1ft section. The arc
of the tape measure blade will not match that of the seat post, but it
will bend to fit. Somehow, attach the tape blade to the vibrating
blade surface. I used epoxy, but that didn't last. Slip the tape
measure blade between the seat post and the seat tube and fire up the
oscillating power tool. The tape measure blade should be thin enough
to fit into the gap, and push the rust and oxide crud out of the way.

Disclaimer: I haven't tried this yet (except on a flashlight).

And while you're at Harbor Freight: http://www.harborfreight.com/11-piec...set-38577.html

Also get a six pack on the way home. Or two.

-- Jay Beattie.