Nachschneiden eines ausgeschlagenen Gewindes in Aluminium

If the hole is truly stripped then the technique in this guide won't work because the hole would then be larger than it was originally and the tap won't bite into the metal and therefore not cut any new threads. So then there are two options:

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1. Choose the next larger size bolt and drill and re-tap the hole to fit that larger size. Or if you really must use the same size bolt then:

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2. Use a helical insert (aka "Helicoil") which is a coil of hardened steel wire that forms both a outer and inner thread.

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I used option #2 to fix a stripped hole in a bicycle shock absorber. I bought the Helicoil kit sized for my bolt from a automotive supply store. The kit came with the drill bit and tap sized for the outside threads of the coil. I drilled the hole, tapped the threads, then threaded the coil into the hole. The inside diameter of the coil was sized to fit the original bolt.

Don is correct that tapping the hole as it exists won't really work and offered some viable solutions. However, if there isn't enough material for a Helicoil to bite into it won't work either on a through hole and sometimes using a larger bolt isn't an option either. In such cases you can add some filler to your existing hole. JB Weld can work as a filler for aluminum. If you apply a thin enough coating, you can tap the hole after it cures without drilling - then use a Helicoil for strength. Option 2 would be to use an aluminum filler rod and a MIG welder to fill, then drill and tap the hole.

Another option, is to drill and tap a larger hole and drive a threaded rod into the hole, grind both sides off flat, then drill a hole into where the threads mesh and lock the two together with a locking pin, then re-drill and tap a hole to match the original. Its more convoluted, but it’ll work if a helicoil won’t work, and the replacement would be very strong.