A good reason to lubricate!

[Grip]

Funny you dug this up right now as we just had another bastard seat post stuck (in a Curtis) this week... without doubt these have been the hardest two jobs I have ever done.

When we couldn't get it to budge one freakin iota we tried to "pump" this last one out using a hydraulic motor and pump from a forklift, but the seat post was so well stuck that it only succeeded in blowing out a weld elsewhere on the frame. We then cut the length of the seat post in half and tried to fold it in on itself and therefore break the bond it had formed with the seat tube... but no go.

In the end I had to drill a 5/8" hole through the underside of the bottom bracket shell and right up into the seat tube. Then we managed to press the seatpost out from the bottom using a 20,000 kg press... but not before denting the top of the top tube (unavoidable ).

I SERIOUSLY hate stuck seat posts... so PLEASE lube the bloody things

 

[Deniss]

Boooooo. I wanted to see some scud missile action!

I use porter powers at work nearly every day there so much fun it's amazing what you can do with them.
I once blow a 65kg high tensile pin over 40 meters the only thing that stopped was a tree. That’s what happens when you get a physco with a 200 ton hydraulic ram a 1379.3 bar, 20000psi porter power unit good fun.

 

[chuckies_here]

Holy shit
Thats so crazy and it goes without thinking to just try it without grease
most of us would do it

 

[arpit]

Maybe theyre just built so they dont leak

I'm sure Fox forks are built so they don't leak too


"Background: A high-pressure injection injury should be considered a potential surgical emergency. Immediate decompression and thorough cleansing of the offending material from the tissue is required to preserve optimal function.

Pathophysiology: Acute injury is caused by introduction of a foreign material, under high pressure between 2,000 and 10,000 psi, into the poorly distensible digital or palmar tissues. The pathophysiology involves acute and chronic inflammation and foreign body granuloma formation. Damage results from the impact, ischemia due to vascular compression, chemical inflammation, and secondary infection. Highly viscous substances (eg, grease) require higher injection pressures than paint or solvents.

Fuel and paint injections lead to the most severe inflammatory response with a high incidence of subsequent amputation. Grease- and oil-based compounds may lead to oleogranulomas with chronic fistula formation, scarring, and eventual loss of digit function. For a photo demonstration of hydraulic injection injury, see Cornell Farmedic Training Program, Hydraulic Injection Injury.

Mortality/Morbidity: Overall incidence of amputation approaches 48%....
Sex: These injuries are rare in women.

Age: High-pressure hand injuries usually occur in young men while working, most often to their nondominant index finger. The average age at time of injury in one large review was 35 years (range, 16-65 y). These injuries occurred to the nondominant hand 76% of the time. "


The injuries start of looking like this from pinhole leaks :

But are very serious.


This is a pic of a guy's hand which got injured when a hose split. As you can expect, its not pretty!
http://www.steamscenes.org.uk/ttu/00001694.jpg



Grip, good job thinking that technique up! That's one of those things I'd never have the ingenuity to come up with, or the guts to actually try it.

 

[nickmann]

ouch! i think the moral is get a seatpost with grease..shit loads of grease

 

[Spanky_Ham]

Well, if grip tells me to lube my post, damn, lube my post I will - repeatedly.

he heee hee

Im so immature.

 

[exvitermini]

wouldnt using the hydraulic motor and pump push the walls of the post(against the walls of the seattube) out meaning more pressure would be needed then if you could find a way to direct the force straight down or up(depends on your prespecive) on the post?

 

[STS01]

"Background:

Pathophysiology:

Mortality/Morbidity:

Nice summary!

It can actually be acutely life threatening as there is the potential for embolisation (entry into a blood vessel and movement to somewhere it shouldn't be) which can cause stroke, respiratory failure and acute heart failure. High pressure air is also capable of doing this. There are numerous reports of people getting badly injured from apprentice initiations and pranks with high pressure grease / oil / air.

You're right it's serious

 

[Chamelion]

I wiped my grease off because my seat post kept sliding down... I might re-think that idea and invest in a more solid seat post clamp.

 

[Pete J]

All of this reminds of a story an old workmate told years ago...
His grandson was quite young and had just learned to paint at pre-school, so his folks bought him some paint and brushes to use at home. (Some people might have already guessed where this is going) Not long after he got a brainwave of sorts and decided that sticking one of his smaller brushes down the eye of his 'old-fella'. Which was all well and good if only it hadn't gotten stuck! So they had to make an emergency dash to the hospital for another kind of post extraction.
All i could say was 'Ouch!!!'

 

[Grip]

wouldnt using the hydraulic motor and pump push the walls of the post(against the walls of the seattube) out meaning more pressure would be needed then if you could find a way to direct the force straight down or up(depends on your prespecive) on the post?

I suppose it would theoretically/minimally, but I'm certainly not going to attempt the math on such a thing. All I know is it works... most of the time .

And there's no problem in finding a way to apply pressure as you mentioned (just see my description of drilling through the bottom bracket shell etc) but it really is an absolute last resort because the problem is that you have to push AGAINST something... and that something is the frame (obviously, or this wouldn't work)... which may end up being dented by the process.

As I said, the Curtis did end up with a dent the size of your thumb in the top tube... but at least it's a useable frame again and the dent can be covered easily.

 

[sawtell]

Anyway, this thread really isn't just about this seat post. It was meant to be a bit of a warning about lubrication in general.

haha i rember this thread the first time around


and i remember laughing at that line as well!

damn im childish

 

[Turner_rider]

Grip:

With both stuck post stories you mention here do you know whether the post or frame measurements were actually what they reported to be?

In my experience I've seen quite a few posts with poor tolerances (or stamping) and some have been 0.2mm out from what they said they should be.

Jamming 27.2mm posts into 27.0mm frames also seems to happen more frequently than it should... Not that this was the case here.

 

[Grip]

Grip:

With both stuck post stories you mention here do you know whether the post or frame measurements were actually what they reported to be?

In my experience I've seen quite a few posts with poor tolerances (or stamping) and some have been 0.2mm out from what they said they should be.

Jamming 27.2mm posts into 27.0mm frames also seems to happen more frequently than it should... Not that this was the case here.

Good point. I can't remember what the post size was on the Turner, but the recent episode with the Curtis proves to be interesting when I pull out the micrometers.

The Curtis had a 27.2 post and a shim. I've always hated shims with a passion and now I know why. I'm reasonably confident that the 27.2mm post, being held only by the 70mm long shim, was able to move around enough (further down the seat TUBE) to "spool up" very badly and jam so completely.

 

[Turner_rider]

Good point. I can't remember what the post size was on the Turner, but the recent episode with the Curtis proves to be interesting when I pull out the micrometers.

The old photos show 27.2 on the post that was inserted in the Turner, and Turners are almost always take 27.2 posts (early burners take 31.6).

I may be a little biased but I trust Turner's tolerances more than that of some seat post manufacturers, but it sounds like we'll never know which was at fault.

While we're on the subject of posts and frames, I know there are a few frames which flare out from the seat clamp area, such that at most the post is only in contact with ~3" of the frame internally. Any thoughts on the pros and cons of this?

 

[Grip]

While we're on the subject of posts and frames, I know there are a few frames which flare out from the seat clamp area, such that at most the post is only in contact with ~3" of the frame internally. Any thoughts on the pros and cons of this?

Hadn't really though about it specifically, but suppose that if it can move it can probably "spool"... which means to pick up a small piece of either the seat post or frame material (depending on which one is tougher) and just keep on working away at it making it bigger and bigger. Just think of the old cartoon snowball rolling down the hill picking up more and more snow and getting bigger and bigger.