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-   -   Pipe Clamp 1 , Stuck stem 0 (https://www.bikeforums.net/classic-vintage/727356-pipe-clamp-1-stuck-stem-0-a.html)

ebr898 04-13-11 08:21 AM

Pipe Clamp 1 , Stuck stem 0
 
1 Attachment(s)
I managed to win one with the assist of a pipe clamp. It may have been a diffrent outcome, if the stem was bottomed out. Here is a photo because it is worth a thousand words.

divineAndbright 04-13-11 08:44 AM

So you pushed it further down, to break the bond I gather? I tried that once, it went down alright, but still never came back out for some reason.

ebr898 04-13-11 09:10 AM

Mine only was oxidized together about 1/4 the way around, and about an 1 1/2 inches up. I soaked it with Liquid Wrench as I pushed it down. I am going to try a super stuck Bridgestone Kabuki that I had to cut off.

nlerner 04-13-11 09:37 AM

Of course, the downside to that approach is seeing your head tube buckle!

Neal

ebr898 04-13-11 09:54 AM

I do not want to sound "slow", but I do not understand how I would buckle the head tube. Even if the stem was bottomed out ( which would make using the clamp pointless) wouldn't the pressure would be on the steering tube? Again I am NOT being sarcastic, I honestly want you to explain it to me, because I do not see it.

cudak888 04-13-11 10:01 AM

I wouldn't try that on any frame of decent tubing.

-Kurt

nlerner 04-13-11 10:05 AM


Originally Posted by ebr898 (Post 12500679)
I do not want to sound "slow", but I do not understand how I would buckle the head tube. Even if the stem was bottomed out ( which would make using the clamp pointless) wouldn't the pressure would be on the steering tube? Again I am NOT being sarcastic, I honestly want you to explain it to me, because I do not see it.

Well, I'm imagining the physics of it is that something has to give once you exert all of that force on both sides of the head tube. The hope is that it's the bond between the stem and the steerer. If not, it might be a headtube lug or the headtube itself. Heck, I had a Raleigh fork dropout fall out when I was trying to remove a stuck stem by putting the stem in a vise, installing a wheel and trying to rotate the fork. It had very little brazing material holding it on.

Neal

tugrul 04-13-11 10:33 AM

Undoing the headset and letting the fork float would spare the head tube the compression.

However I would guess the steerer is stiff enough to endure this and keep the head tube from harm. I imagine this is probably the least stressful way of budging a stem short of cutting it out.

Somebody like Frank should weigh in though.

ebr898 04-13-11 11:10 AM

Thank you tugrul, you pointed out what I was missing.
The threaded steering tube being connected to the head tube via headset. I was thinking the compression would cause shear force where the steer tube rides over the stem.
Wouldn't the threads be one of the strongest areas? Because it is overlaped so sideways pressue (if any) would not bend the "telescope" where it is reinforced.

rhm 04-13-11 11:21 AM

You took a chance. I'm assuming you'd already knocked the wedge out of the stem, and the stem was still stuck; so you applied force. Your gamble was that the corrosion holding the stem would be the first thing to break. If it hadn't, you could have applied enough force to buckle both the steerer tube and head tube. You assumed you had enough sense to not apply that much force; and I think that's a pretty good assumption, but unless you knew exactly how much force it would take to do each of these things, it was still a gamble. I'm glad it worked!

RobbieTunes 04-13-11 12:03 PM

I'm glad it worked.

My gizmo aptitude stops at the bigger hammer.

randyjawa 04-13-11 12:06 PM

There is no pressure on the head tube. All of the high energy will be directed through the stem, and resisted by the bottom of the steering stem/for crown joint. I could be wrong, but it looks like it is workable and without great risk.

Not a bad idea, but generally, I prefer to cut a really stubborn stem or post out. One damaged frame set, is enough for me and that frame was a nice old all chrome plated Torpado. I destroyed it, accidentally, by using too much force to break the seizure.

bennie222 04-13-11 12:37 PM

Good idea for the stem removal by the OP. I just performed my first chemical extraction of a stem on a Gunnar. It took about two weeks of soaking in lye and some coaxing. The stem was thick, so it had to eat through a lot of material. I took it out occasionally, cleaned it, used a wire brush to expose more fresh aluminum, then dropped it back in the bucket. I eventually got tired of this process, and cut two slots through the stem, it still wouldn't come free, so I just soaked it some more. The slots helped the lye work away at the stem where it touched the fork and it eventually came loose.

Submerging and soaking is a viable option for stuck stems, but not for a seatpost. The same bike also has a stuck seatpost, so I'm trying to cut it out now. what a pain. I did find that a regular hack saw blade fits pretty well in my Ryobi sawzall which definitely helps with the cutting. I'm trying a bit of both on the seatpost now, two cuts, mounted in bike stand so seatpost is perfectly horizontal, and used a dropper to squirt a bit of lye in the cut. This way it doesn't get all over the frame and destroy the paint. I'll do this for a few days on one side, then flip it over, and do the same to the other crack, we'll see how it turns out.

Mike Mills 04-13-11 01:47 PM

You can also flip the movable clamp head on the pipe and use the hand screw to pull them apart rather than push them together.

ebr898 04-13-11 02:33 PM


Originally Posted by Mike Mills (Post 12501919)
You can also flip the movable clamp head on the pipe and use the hand screw to pull them apart rather than push them together.

I love the idea, but don't see how to do that without causing side pressure on the stem/ fork. Could you explain how you grip the stem and steering tube.

Mike Mills 04-13-11 06:32 PM


Originally Posted by ebr898 (Post 12502170)
I love the idea, but don't see how to do that without causing side pressure on the stem/ fork. Could you explain how you grip the stem and steering tube.

Put one end beneath the stem and the other on top of the fork crown. If it won't allow for that, install a bolt (in lieu of the brake) and push on that.

You could also go beneath the stem and on top of the fork crown. This puts the clamp faces at 90 degrees to each other but might also work.

Necessity is the mother of invention.

I haven't used them for this purpose but I have used them to pull things apart. It doesn't even have to be bike related (Sacriledge!).

Did you try the "beat it with a hammer" technique before you tried this? Sometimes shock is better than steady pressure to loosen frozen parts.

I like what you did. I use my clamps for all sorts of things. I keep pipe sections in all sorts of lengths to adapt them to the job at hand. 3/4" pipe is cheap.

Was it totally frozen or could you just not get it to come out? Did it "pop" loose or slide loose?

ebr898 04-13-11 07:19 PM


Originally Posted by Mike Mills (Post 12503205)
Put one end beneath the stem and the other on top of the fork crown. If it won't allow for that, install a bolt (in lieu of the brake) and push on that.

You could also go beneath the stem and on top of the fork crown. This puts the clamp faces at 90 degrees to each other but might also work.

Necessity is the mother of invention.

I haven't used them for this purpose but I have used them to pull things apart. It doesn't even have to be bike related (Sacriledge!).

Did you try the "beat it with a hammer" technique before you tried this? Sometimes shock is better than steady pressure to loosen frozen parts.

I like what you did. I use my clamps for all sorts of things. I keep pipe sections in all sorts of lengths to adapt them to the job at hand. 3/4" pipe is cheap.

Was it totally frozen or could you just not get it to come out? Did it "pop" loose or slide loose?

Ok I get it. I think that would work, better than drilling a hole in the cast iron clamps, which is what I thought of when I was trying to figure out what you were discribing, It decended slowley after it had been "loaded" pretty good. It did not "snap" like the crank cotters when they released ( bench vise and sockets).


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