If you’re lucky, the left-handed bit will grab and unscrew the bolt enough by itself for you to grab the bolt with a pair of vice grips or channel locks and finish removing it from there. Make sure you use the appropriate size drill bit. The bits in the extracting kit should have a table letting you know what size to use based on the size of the bolt you need to remove. Using too big a bit will risk damaging the threads on the bolt, and using too small a bit will require a smaller, weaker extractor with a higher risk of breaking off during the process.
Since the extractor is tapered, you should initially tap it into place with your hammer before switching to a socket or T-handle.
Continue turning the extracting tool counterclockwise until the broken bolt has been completely removed from the surface in which it was embedded. Be sure to take your time during this process to prevent excessive damage to either the bolt or the item from which you are removing it. You also want to work the extractor as gently as possible because they are made of hardened steel, and a broken off extractor will be even more difficult to drill out.
This method of extraction is typically reserved for bolts that are too corroded to be removed with an extractor, so you do not need to worry as much about tightening the bolt while drilling it out with a right-handed bit, but using a left-handed bit can’t hurt.
Be especially careful if the surface into which the broken bolt is embedded is one that will melt to the steel bolt or nut. Because of this, this method works best against a surface such as aluminum, which does not easily weld to steel.
The weld is strong, but it will not be unbreakable. For especially corroded bolts, the nut may have to be welded back in place more than once. In order to break the corrosion bonds, try slowly working the bolt back and forth initially. Once it starts to loosen, continue working both directions but more so counterclockwise, so you can begin removing it entirely. [8] X Research source
