LCGB Forums

Just trying to remove sheared off horn casting screws. Soaked them in plus gas for 2 weeks then applied heat with heat gun. Success, managed to get one out but 3 more to do and I don't really have enough metal to grip onto?

Can anyone suggest other ways to remove? Drill out/stud extractor? Being dissimilar metals they really do weld themselves in there and I worry if I apply too much force it will break the casting.

What about spark erosion?

Wouldn't it be great if LCGB had a spark eroder for the use of all members, & all that would entail being a nominal fee with P&P costs?

I think you may be able to get quotations, but the cost prohibitive.

The alternative is to drill out the corroded steel screw remnants. With patience & care, it can be done.

Unless you are very steady handed & have access to an electric/battery drill that can go very, very slow, a pillar drill is best. I have got them out using drill bits in a Milwaukee 18v brushless Combi but that is one of the best hand tools TBH.

Beware centre dotting too much the broken screws or they work harden. Using good, fresh drill bits (split point are good) drill as slowly as you can with a good cutting fluid with, say, a 2.5 mm drill. If you are accurate, that can then be followed up with bigger drill bits until the remnants virtually collapse inwards. The fasteners are usually M5, so 4.2 bit is the largest size to go.

Follow up with a tap, or, if the drill wandered, get the holes Helicoiled.

Fit with replacement fasteners using Copaslip. The bottom holes that secure the mudguard can have (Copaslipped!) stainless studding with nyloc nuts/washers. The studs ensure that the full thread available is used. Much, much easier to fasten/unfasten & virtually future proof.

Good Luck!

I did see somewhere they got a bit of steel drill a small hole in it then spot welded it through the hole to the top of the sheared bolt

Thanks so much for the replies. I am going to think long and hard about how these screws can be removed more easily rather than traditional labour intensive methods.

There has got to be an alternative easier solution.

I use the SDS cutting disc attachement with my Dremel to cut the heads off the duff screws. This then allows the casting to be removed where it can be more easily worked on.
You then have better access to heat the area of interest with a paint stripping gun and using a vice with near new vice jaws you can grip the small amount of stud still showing. Carefully work the casing back and forward to break the bond. If badly corroded, then quite a bit of heat is needed.
Works most of the time but not all of the time.