Removing weld
 

Hi all.

Problem with my bike and would love some opinions.

A mechanic in Mexico tried to fix a broken retaining bolt on the front sprocket of my bike and the solution he came up with was to weld the bolt to stop it from coming loose. This was obviously whilst I wasn't there to stop him.

My question now that it has been welded on is will it be possible to get it off again (through drilling or some other way)?

Any help/suggestions much appreciated.

You have various options depending on how it's been welded. He has hopefully just tacked it on at one point - grind the weld off and it should free it up.
He might have welded all round, go round with a grinder and get the weld off, this might involve knacking the bolt head, so grind two sides down and roughly parralel then get some mole grips on it to get it off
If these don't work you could try grinding the whole head and weld off then drilling a small hole and use a stud remover, or drill it out helicoil it back down to the correct thread size. One problem with messing with these bolts is if you (for example helicoil) fix it and don't have a perfectly true/flat surface afterwards your discs will be out of true.....

You're going to have to grind it amigo....

Any basic workshop will be able to do this...

A photo would help !

Ted

Although if the mechanic that did it really was incompetent you might be able to smack it off with a hammer! Have seen welding that failed to joing two pieces completely from being filthy/not prepped...

Yup, I can guarantee that!
Bad preparation of the metals will make a very bad weld!


Good luck with that!
Vando

It all depends how it was welded and how much room you have .
You may not have enough room to get a grinder in there .
If that is the case ,then take it to a competent welder and have him air arc [ gouge ] the weld off .
Put wet rags around the gearbox shaft to keep everything cool and to stop any fire from starting .

If you are going to grind it off , use a very thin disc , like a ZIPCUT and cut through the weld rather than grind it down .
You might be able to find a small dremel type tool that will get into a tight space .

Without a pic...try this.

*You could drill into the bolthead with a drillbit nearly the same diameter as the bolthead. Then use a vicegrip (mole wrench) to remove the stud remaining.

*You could grind away the bolthead and again use a vicegrip.

*You could as suggested above use a thin cutting disc to cut away the weld, or the bolthead.

*You could use a centrepunch and a hammer to loosen/turn the bolt.


Personally I'd just grind it off if the centrepunch didnt work. One minute's work.