Be careful not to use too much force when drilling. If you press hard, the tap will catch the bit and click. Work slow and light and use cutting oil if you have it. You don't fly to the moon, you just drill a hole and thread a thread into your metal. Protect your teeth slowly. Be wise, order two sets. It really saves time. The company stands behind its products. I will buy it again when I need to drill and seal tape in one operation.