Tack Broken Bolt in Aluminum

[ctwo]

We have a motorcycle fork with a stuck bolt, 1/4" allen head is stripped out. We are worried about damage to the fork tube, so my idea is for a competent welder to weld in an allen key or something to the bolt head. Most of the guys think it is impossible to do without melting the aluminum, and the rest think the weld would just break because the tacks wont penetrate enough.

What do you guys know about this sort of thing (welding, not bolt removal, that ship is likely to sail). I think the bolt is stainless, but it might be some other steel.

[hammermill]

If you place a nut over the Allen head and we'ld quickly. Maybe wrap the fork with a wet rag I doubt things would be damaged.

[DavidF]

can you post a picture of the problem? I have removed may a stripped/broken bolt from aluminum. (outboard motors) but need to see what you are dealing with. Welding in a hex may work, also maybe drilling the head off and getting hold of whats left might. It all depends on whats there and what would/may be left...

[redneckalbertan]

Pictures would be great! I would use a 220V MIG welder set relatively high and slightly hot. And would use multiple small tacks. The high settings to get penetration and short tacks to keep the Aluminum from melting. Heat will help break the corrosion, if any. I would let everything cool after tacking and then try heating the surrounding aluminum. The aluminum should expand faster than the steel when hot so getting heat into the aluminum when trying to extract it, and keeping the bolt cool will help, this will be more so with a stainless alloy.

I've never tried to extract a steel or stainless bolt from aluminum, but this is where I would start.

[ctwo]

It is the bottom of the fork tube. The bolt is the next larger 1/4-20 metric size (I think M8), and it is recessed. I do not have a picture, but it is the (10) SOCKET BOLT in this diagram. The last attempt to remove was done with a manual hammer impact driver (the one that you hit with a hammer that twists).

http://s1137.photobucket.com/user/i2ima ... s.jpg.html

[warmstrong1955]

I know exactly what you are talking about. Been there....
Have you tried an easy out?

This kind: http://www.amazon.com/Irwin-Industrial- ... s=easy+out

I have a couple sets of these, Mac & Snap-On brands, so I can't vouch for the quality of the Irwin brand, but I've removed many allen screws with mine. They are short, and the best extractors I have ever used.

just a thought.

Bill

[ctwo]

Thanks, Bill.

This is just a discussion on another forum. Easy-out is the first suggestion following a left hand drill bit. All the certified welding experts that suddenly appeared demand it is impossible to weld anything to that bolt without resulting in a puddle of aluminum, or that the weld tack would simply be way too weak to hold. I believe a nice tig welder who know his stuff would not have a problem with that.

[warmstrong1955]

Yup....a decent TIG and a good welder could do it.....not for the rookie though. Guy would need to get in and get out.....a few times. Something like a nut would work best....it would protect the aluminum from the direct heat.

A few good zaps with a mig could do it, but the weld would tend to suffer from brittleness. I've done that, but in those cases where a bolt is really tight, and you can't get a good weld, the nut welded on often breaks off.

If you try a LH drill bit, get a good one. That area between the base of the head, and the shank of the bolt is hard....like.... hard-hard. I modify many socket head capscrews on the lathe, and I use carbide....and it can be tough on carbide.

I've done many with those short easy-outs.... which would explain why I have so many.

I have another big set out in my pickup....just got back from using it on a hydraulic lift-gate pin retainer bolt.


Bill

[steamin10]

We used an extractor welding rod at work. It is made for welding down through a nut to a broken stud or bolt. It is 120k psi material, and the slag runs to the outside guarding the hole if broke below surface level. bringing up the weld and making a rose on top, and a twist usually does it. Aluminum degrades at 11oo degrees, so it is a factor no doubt. It may also be the key if you warm it to 500 degrees and try to pull the bolt. AL swells about twice the rate of steel with heat.

I have used it on 3/8 bolts and larger with greater success.

Every fixxit guy should have left hand drill set, they often drill and heat the broken stub enough it grabs and pulls it out by itself. Once a hole is made, extractors are the next stop on the road. Good luck with the agrevation.

[Harold_V]

The one thing that has been overlooked is what happens to aluminum when it is heated. I fully expect that the item in question has been artificially aged (heat treated, for lack of a better description). If it is heated beyond a small amount, there's a risk of annealing, rendering the item useless. I'd recommend one go easy if heat is involved. I know from personal experience that a weldment made from T6 aluminum is rendered dead soft.

Harold

[ctwo]

The end result here is that the owner decided to leave the bolt alone and forego a complete rebuild of the forks.

I conclude that I was wrong and that welding would be a bad idea.

Thanks all for helping me.

[mcostello]

I removed 10- 8mm (I think) bolts broken off in a 1995 Mercury Villager head. They used 1 size too small and they break after a bit of time. Got them all, did not have to drill any of them.