This set is amazing. I rounded the head of the external torx screw in my motor. This set worked exceptionally well to remove. Here is my process. First I cut off the head of the screw with a dremel. Second, I made a dot in the center of the bolt with a hole punch and hit it hard with a hammer (a heavy one works best). Alternatively, if you don't have a hammer drill, you can use the smallest drill bit in this set to make the starting hole. Or you can use a Dremel tool to create a notch (like a slot for a flat head screwdriver) on a screw. This gives the drill enough clearance to grab and penetrate the bolt. Third, this set has a chart on the inner lid where you match the drill bit with the screw you want to remove. Choose the right drill bit and start drilling at the dead center of the screw. Make sure you drill straight because if you hit the threads you're done. Since these are left-handed drills, you'll need to drill backwards for it to go in. I recommend practicing on a piece of wood or cardboard to see which direction to drill in order for the drill to penetrate. In short, your drill is the other way around. To drill through the screw you're trying to extract, I recommend pulsing the drill to make sure you keep the drill centered and not skewing it into the thread. You don't have to go super deep. After drilling from 1/2 cm to 3/4 cm, take a screw extractor that matches the size of the screw. There are two types of extractors in this set. T-shape and socket type pullers. The T-type requires a T-tool or vise to manually rotate the extractor. Socket pullers (shown in my pictures) are easier to use. You will need a 1/2" SAE socket attached to a 3/8" ratchet. Take the extractor of your choice and hit it with the hammer in the hole you made with the left club. A few hard hits are enough. Then attach the connector (or if you used a T-puller, use a vise or other tool) and slowly turn it counter-clockwise. Once the screw comes loose, you can remove the rest by hand. If this is the case, keep using your tool until you get the screw out. Finally, to remove the puller from a damaged bolt, you can use two vises or a socket wrench and vise. Twist in opposite directions to loosen. After all, these instruments are made in the USA.