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How to undo a stuck round thing?

Posted: Feb 24 2016 1:25pm
by le15otl
General mechanical question;

I have a threaded extension tube on my bottom bracket which I need to take off. It is incredibly stiff and I'm really stuck...
It's about 1.5'' diameter and I just cannot get it to move.
I've tried two pairs of mole grips at once, with a pole attached to it, but they just slip before the tube budges.
Tried WD40, tried a hot air gun, it will still slip before moving.

Anyone know of a way to grip a round nut/tube extremely tightly and be able to get a lot of leverage on it still?
I don't really want to weld onto it.

Thanks :)

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 1:52pm
by Drunkskunk
Extension tube off the shell, or off the crank? You remember that some of these are reverse thread, right? :mrgreen:

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 1:54pm
by spinningmagnets
Sounds like it will be damaged in the process of removing it. Once I reach that point, I typically start cutting pieces of it away. When you get down to the part that last little bit that is threaded into the BB, run a hacksaw blade in and out to make a perpendicular groove, then hit that groove with a chisel and hammer (just hold a bare hacksaw blade with your gloved hand and stick it in the hole). That should cause the groove to crack all the way through. Repeat as many times as necessary. Or maybe use a pointy chisel and cave that last remaining section in towards the center.

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 4:24pm
by le15otl
Extension tube of the shell, and yeah i remember but the other side is reverse thread so i'm fairly sure this side will be normal :D

I don't really want to cut it away as i believe it will be hard to find a replacement part, but that is helpful detail on how to do it, if it gets to that point.

It was only tightened a few weeks before so I still have some hope :?

Cheers

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 5:39pm
by Hillhater
Gas torch !
Get it real hot quickly
Pipe wrench or chain wrench.
Take no prisoners !

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 6:41pm
by Punx0r
For applying lots of torque to a round thing it's hard to beat a pair of Stilsons (pipe wrench).

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 6:52pm
by bowlofsalad
Punx0r wrote:For applying lots of torque to a round thing it's hard to beat a pair of Stilsons (pipe wrench).
Great suggestion. To add to this, to gain or increase leverage a way to do is to lengthen the arm of the tool you use to apply force, this is often done easily with a piece of round or square steel tubing, that is how I do it at least.

https://www.youtube.com/watch?v=XhuxbqCUxnA

Re: How to undo a stuck round thing?

Posted: Feb 24 2016 8:39pm
by Hillhater
The right tool won't need no extension Cheeter bar .....

Image

Re: How to undo a stuck round thing?

Posted: Feb 25 2016 9:40am
by le15otl
YES IT WORKED!

Pipe wrench + hot air + long scaffold tubing = success

Never thought a pipe wrench would work that well...

(I'd love to get that huge one :D )


Thanks all!!