Screw Extractors

For those who don't know about these they can be really useful sometimes. If a bolt or screw has a busted head or is badly rounded off then a hole is drilled into the bolt. Start with a small drill then use the appropriate sized drill for the extractor being used. The extractor has a very coarse left hand thread and when inserted into the drilled hole and turned anti clockwise it bites in to the drilled hole until it starts to undo it.




A little example -- The bolts that hold the coolant reservoir had previously been put in with a rattle gun or something. They had melted a hole into the plastic body and were so far in it was impossible to get a spanner or pliers onto the head. I considered breaking the reservoir :bang: but then thought about the extractors. A little hole was drilled and the extractor removed the bolt easily.










There is also female type version available that I reckon would be really useful at times to. This was recently mentioned in a stuck wheel nut thread.

I would add a word of caution to using Screw Extractors, or "Easyouts"

If the reason the bolt is stuck is the head has rounded off or sheared off then, unless you can free the threads, then a screw extractor will probably not remove the screw.

What can happen is the screw extractor can snap off in the hole you just drilled. This then means that you have a hardened steel insert stuck in the middle of the screw which makes it very difficult to drill out.

I do use these, and used one recently to remove a sheared off stud in a k-series engine, but you have to be fairly sure that there is a good chance that the offending bolt/screw can be removed.