Stripped out 6 mm Allen key hole

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EOsteam
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Stripped out 6 mm Allen key hole

Post by EOsteam »

I'm replacing a water pump in my VW Corrado and wouldn't you know it but the last of the three 8 mm x 1.25 pitch bolts holding the pulley stripped out the 6 mm Allen key hole.
What are my options
1) I've never had much luck with drilling and using an easy out. They always seem to break even more and now there is a piece of hardened steel stuck in the hole
2) Weld a nut to the bolt head. I'm not a great welder but have a TIG torch. The welder also has a stick welder holder which I have never used.
3) Left handed drill?
4) Is there some cool tool that you can bang into the stripped out Allen Key recess and will grab and turn?

Please let me know as the probable next option is ordering something from MSC.
Thanks,
Harper
John Evans
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Re: Stripped out 6 mm Allen key hole

Post by John Evans »

Option 2 ! as long as the head of the of the Allen head cap screw is not recessed . LH drills work great but not with the bolt head still attached and under torque . And HSS drills do not work well in Allen head bolts -set screws etc.
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EOsteam
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Re: Stripped out 6 mm Allen key hole

Post by EOsteam »

Is there a nut that doesn't have Cadmium based plating on it?
armscor 1
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Re: Stripped out 6 mm Allen key hole

Post by armscor 1 »

Had the problem on an Isuzu, hammered in a Torx driver bit and got them out.
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liveaboard
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Re: Stripped out 6 mm Allen key hole

Post by liveaboard »

It's always different depending on the circumstance.
I favor welding to the problem bolt or stud. Not a nut, but a big chunk of rod or something.
However, this is not an easy weld to make. If you're not well practiced then it's not a good technique for you.
Go for Armsror's idea first, or grind a slot into it and use an impact driver.
As the old waterpump is still on there, no need to worry about the surrounding metal I assume.

I have no luck with easy outs. But if you can drill off the head and remove the pump, you can probably take the stub out easily.
Inspector
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Re: Stripped out 6 mm Allen key hole

Post by Inspector »

When trying to remove screws from aircraft that had been in long enough to become one we would invariably break screw extractors in them. The sheet metal guys came along and used a small "rosebud" carbide rotary file to grind out the broken extractor and then carefully open the hole until the head popped off. After seeing that it was easier to start with the rosebud and take the head out to begin with. The bit was a little ball with fairly coarse cutting edges about 1/8" in diameter but were were taking out #8 and #10 screws. A slightly bigger bit should centre on the worn Allen hole and eat its way in easily. Try on a bolt held in a vise to practice with.

Pete
John Evans
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Re: Stripped out 6 mm Allen key hole

Post by John Evans »

EOsteam wrote: Sun Aug 01, 2021 11:03 pm Is there a nut that doesn't have Cadmium based plating on it?
Most likely zinc plating nowadays ,cad has not been in general regular use for quite some time. Back in the 90s had to go to a aircraft plater to get cad when we were restoring motorcycles.
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Bentworker
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Re: Stripped out 6 mm Allen key hole

Post by Bentworker »

2nd on hammering a torx bit in the stripped head. That is a pretty solid method of dealing with a stripped socket head bolt.
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Harold_V
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Re: Stripped out 6 mm Allen key hole

Post by Harold_V »

EOsteam wrote: Sun Aug 01, 2021 11:03 pm Is there a nut that doesn't have Cadmium based plating on it?
Unless you have exceedingly old stock, the likelihood of having a nut with cad plating is highly unlikely. Cad plating tends to resemble (frosty) silver in color, while zinc has a distinct blue tinge. The use of cadmium has long been discontinued because it is toxic.

If the plating on the nuts you have have a gold overtone, they're most likely plated with zinc. The gold color, an iridite finish, offers greater corrosion resistance. If you have access to a little hydrochloric (muriatic) acid, drop a nut in a small volume. The plating will dissolve almost instantly. You can use sulfuric or nitric just as well, but handle them carefully. Hydrochoric is the safest of the three to handle. You can use acetic acid (vinegar) too, but it will react much slower. You might also enjoy success by placing a nut in a carbonated soft drink of your choice---many of them contain either phosphoric or citric acid.

H
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wildcatter
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Re: Stripped out 6 mm Allen key hole

Post by wildcatter »

I would weld a nut on. Can be tricky to do with only 2 hands but you need the practice,no ?
rrnut-2
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Re: Stripped out 6 mm Allen key hole

Post by rrnut-2 »

Are you sure that it is Allen? VW likes to use a triple square torx bolts.

Jim B
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