Top positive review
25 people found this helpful
Worked surprisingly well
on August 13, 2011
It is important to follow the instructions precisely, otherwise, yes, there is a good chance that if you are heavy-handed you can just destroy the screw-head and leave yourself in a mess. Used correctly, however, these extractors work great on stripped screws. I haven't tried drilling into a bolt-head, but it looks like that would work too.
There are two ends on the bit, the burnishing end and the extraction end. Extraction is a two part operation. The key is to use as little brute force as possible to get the job done.
The first part involves using the burnishing end to drill into the top of the fastener. Go easy with this, as it looks like it is possible to burnish too far into the screw or bolt shank and potentially make it impossible to go to step two. On the other hand, the hole created with the burnishing end must be deep enough that the extraction end can grip the screw or bolt. (Burnish a bit, try to extract, if the extractor doesn't grip, burnish a bit more, etc.)
The second part is where the magic happens. Switch the bit to the extraction end. The drill must be in reverse. Very slowly go into the burnished hole (which must be deep enough), and try and get the extractor to grip the inside of the screw. Once you have a grip, then slowly increase the power on the drill until the bolt begins to turn. It will come right out.
Bear in mind this tool is for stripped heads, not necessarily for seized bolts. If you stripped the head of the fastener trying to undo the bolt in the fist place, then it may be that the thread is seized; try to burnish an extra deep hole to get as much grip as possible. Also, consider the old trick of using penetrant and heating the fastener with a torch as this may help free the bolt.