Broken set screw.........

Tom Fleming · Mar 9, 2010

I was preparing to remove the front pulley off a C113. Pully has the set screw. removed jamb nut with no issue. heated pully a bit and started with the allen wrech........SNAP.

Broke off just below the surface. Not enough room to get a center punch in to back it out that way. Colbalt bits won't touch it. Not enough of the hex hole left to try an extractor. I could probably muscle the pulley off, but that will certainly score the crank, if I can even do that. I can certainly split the pulley, but I would prefer not to do that.

Thought about drilling the cast around the set screw, then snap it out, and drill and tap with a larger size. Probably the way I will go.

Any ideas?

Anonymous-0 · Mar 9, 2010

EZ out. There are a variety of screw extractors. I'd try that route before more destructive methods.

Anonymous-0 · Mar 9, 2010

At times I have been successful taking a good nut and with the broken stud vertical. Electric Welding the stud to the nut being very careful keeping the weld arc on the broken stud and melting it to the nut by building up weld, there by attaching the nut to the stud.. Do be careful espesically on smaller studs..

Anonymous-0 · Mar 9, 2010

If you can get a small torch head into the screw, heat it up as much as you can & let it cool, but not get the crankshaft hot. Goal is to draw the hardness from the set screw to make it more drillable.

Also, don't run your drill too fast & keep it well lubed.

Solid carbide drills are avaialable, but are pricey. Feed VERY carefully, as they can snap easily if they catch an edge.

Tom Fleming · Mar 9, 2010

Thanks guys. this is a 5/16" set screw, and it is broken just below the surface. EZout isn't an option, as there is no hole ( or very little, 1/8" maybe). Not sure I can get the MIG in close enough on the 5/16" nut to get a weld that will hold.

Might look into a 1/4" carbide burr, and work my way down with the Dremel.

Thanks for the input. That set screw is God awful hard. I have drilled set screws out before with the Cobalt bits.........but not this one.

tjiniowa · Mar 9, 2010

Sometimes had luck with left hand drill bits.

teddy52food · Mar 9, 2010

Easy- out is the last thing to try. They only work if it comes out easy. A bolt that twists off will not come out with an EZ out. When you break that off , they are so hard they can't be drilled.

Anonymous-0 · Mar 9, 2010

there is aspecial welbding rod made just for these situations.I dont know where to get it. try a welding supply store.I think Farm Show had a story about this

Broken set screw.........

Tom Fleming

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Anonymous-0

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Anonymous-0

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Anonymous-0

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Tom Fleming

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tjiniowa

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teddy52food

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Anonymous-0

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