Working properly 12

I had a small steel screws at the bottom end with a head completely smashed to extract in an aluminum body. A quick drill with a metal drill bit size needed to prepare the ground. I do not have to mark the center of the screw, what remained of the screw head was already in the middle. A little penetrating oil. Is allowed to act. I used the extractor with my viseuse really very very slowly from there (maximum torque, minimum speed), although orthogonal to the work plan and using moderate (to avoid breaking the extractor, the materials is very strong but has no flexibility and may break the glass so). The extractor took a good catch and I pulled out the screw, still at a rate of senator. After the operation, the extractor was still in good condition, and the thread of my aluminum body had no damage.
-> The key for the extraction, it is really using the right size and the right drill extractor size. Take your time, do not force, to understand the constraints. There are other types of extractors (point with 2 blades) but it needs the support is fairly soft (wood, plated against), the technique can damage the media (it must exert very strong pressure, it is very nag) and totally ruin what was left of the head of the screw (nag ... I've said?).