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I urgently need to learn to weld just a little bit. I am trying to replace my bike's clutch friction plates, but one bolt on the pressure plate has refused for days to loosen, and is now slightly rounded. I tried cutting a slot in it for a screwdriver, but the bolt head is recessed, so the slot isn't deep enough. It is only an M6, so it won't be too easy to use an easy-out on. I have one, but it tapers up to about 4mm, so if something there goes wrong I'm up sh*t creek. Someone suggested welding a steel rod to the head and turning it loose with that, and that makes quite good sense to me; a weld will never slip.
Thing is, I have never welded before. I know the basic theory, how to strike an arc, maintain a pool while wealding along a line etc. but have never tried. Never had a welder before.
To weld to the bolt head I will probably just have to strike an arc and hold it for a second.
What advice can any experienced welders here please give me for this, and NB stuff to practice a little bit before trying?
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I don't weld - but I've seen enough people do it to know it ain't that simple! There is some real skill involved here, and if you get it wrong you can make the situation worse, not better.
This is a bike - so the chances are that the bolt is not steel, it's aluminium alloy - which will have a different melting point to the steel, so it may be harder to weld than you think particularly if the head is recessed.
Have you tried tightening all the other bolts and using an impact driver? Or do you know anyone who can weld, you can run you through it? I find people who can weld are generally susceptible to bribery in the form of ![Beer | [beer]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/beer.gif)
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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OriginalGriff wrote: I find people who can weld are generally susceptible to bribery in the form of [beer]
FTFY 
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It's a steel bolt, and I'm too broke to bribe anyone to travel all the way to my house and help.
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Brady Kelly wrote: I'm too broke to bribe anyone
So how much is a new clutch basket, if you really muck it up?
Seriously - how much? It may be cheaper to just say "to heck with it", drill the head off the bolt and replace the basket if you can't get the remains out later. Clutch baskets have to be spot on - or the pressures won't be even, and the clutch will either drag or slip - and extreme localized heating is a good way to warp things.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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Drilling the head off won't mean replacing the basket. Maybe a good idea, then I can work on the bolt shaft, maybe bend it and get a better turning grip on it.
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That was always my prefered way to deal with it: drill the head off (just use a bit slightly smaller than the bolt shaft: it'll crumble when it's ready) - remember to refit the other bolts first and get a replacement bolt.
Once the basket is out of the way you can get creative - a hacksaw on the bolt end to make a good size slot is always useful.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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Good points Griff it would be better to take it to a pro welder. You don't know what the bolts are made of, could be stainless or ?? but if you don't know and try to weld it won't work and you'll end up screwing it up plus what is he going to weld it with?, does he own a welder?
Along with Antimatter and Dark Matter they've discovered the existence of Doesn't Matter which appears to have no effect on the universe whatsoever!
Rich Tennant 5th Wave
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I have a nice welder, inherited from my father. The bolts seem plain steel, not stainless. It's a cheap Chinese bike - no cost-cutting spared on it.
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Gotcha, so you won't be out a lot whatever method you try.
Along with Antimatter and Dark Matter they've discovered the existence of Doesn't Matter which appears to have no effect on the universe whatsoever!
Rich Tennant 5th Wave
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I know you've solved the bolt problem by now, Brady, but for future reference, aluminum and most stainless steels are non-magnetic, which yields a quick and dirty test before you weld.
Will Rogers never met me.
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Thanks. I'm quite a good mechanic, and can normally tell metals etc. but this could always come in handy.
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I'm speaking at a level of knowledge of someone who thought an arc welder was something Noah used, so treat appropriately.
trying to weld to the end of a bolt that is recessed sounds to me like a recipe for disaster - one slip and you're making the bolt even more permanent!
Also, isn't heating the bolt going to expend it and, again, likely fix it more firmly in place?
If it is at all possible (I have no concept of the sizes involved here) I'd try cooling the whole thing down. If you can get that metal to shrink, it may free the bolt enough to be able to get it to move; not particularly practical if it's still attached to the bike, though 
You could also try heating it. If you can heat the bolt without heating the surrounds too much, it will expand and push against the corrosion that I imagine is keeping it stuck. When it cools again it may be free enough to shift.
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It's a tiny bolt recessed into an aluminium pressure plate. I will try to not touch the aluminum plate, and will risk no mask for this quick weld. But I like your idea of heating and cooling the bolt. That still leaves its head a bit rounded though.
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Sounds like the saga I had earlier this year when I had a recessed locking wheel nut siezed on my car.
We condsidered the welding option, but high risk of damage to the wheels as they were special coated. In the end my pal used a tungsten carbide hole saw to core out the head of the bolt (took 4 hours) to allow the wheel to get off to then allow enough room to get in with something to grab the stud. To alleviate a risk of damage from welding splatter it is possible to use a soda can cut into a thin strip and sprung into the hole to act as a barrier.
You might consider hamering in an allen socket into a hole drilled into the rounded bolt. depending on the recess/bolt head ratio, the hammering on a socket could be an option (but doesn't sound like it).
The other option is a shallow multi splined socket extractor, like these here[^]. Don't need as deep a hole as an ez-out and more teeth to bite.
There are videos on Youtube on using welding to remove siezed bolts.
Good luck, I think at least the bolt you are removing wont have been as hard as special steel alloy in the bolt I was trying to remove, it took an eternity just to drill a small 3mm hole using a brand new titanium bit!
Don't forget to drown in penetrating oil, and also go for the heating and cooling option first. get a narrrow tip flame, you can get these at the local diy shops.
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I'd love that set of hex screw extractors, after payday, Wednesday, but today I could afford only one beer one the 5km return walk to the hardware to not find a decent 8mm socket. I have already rounded two non-decent ones.
I have an easy-out that may just do the job, and will try after the heating trick.
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There's another option here:
1. Use a drill to make a bigger hole than the screw itself (drilling through the screw).
2. Use a threadformer to create a new thread.
3. Get a new and bigger bolt with a proper head.
4. Screw that bolt onto the newly formed thread.
Done.
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Drilling through steel with a 6mm bit on a hand drill isn't my idea of fun at all. It's on the bike, so I can't use the press drill.
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Probably way toooo much fun... 
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Have you tried heating it first? That seems to work for the Wheeler Dealers.
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That generally works for nuts, not bolts - it expands the metal so hot nuts get bigger and looser. Hot bolts get bigger and tighter.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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I'd go with Dave Auld's or Davex86's suggestion. Joan Murt's suggestion is good unless the bolts are attached to something spinning. There is a danger of throwing the balance out.
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Brady Kelly wrote: What advice can any experienced non welders here please give me for this
Wear goggles.
Not while goggling but during welding. 
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We've got something better![^]
Found this old Dilbert last week. Still makes me laugh
It's an OO world.
public class SanderRossel : Lazy<Person>
{
public void DoWork()
{
throw new NotSupportedException();
}
}
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