Rotation frequency. A very important factor, different materials are drilled at different speeds. For example, when trying to drill a steel plate at high speeds, you will just burn the drill. In fact, the reliability of the built -in mechanism for adjusting the revolutions comes to the fore. Because all drills are able to regulate the momentum. Try to touch in the store, twist the speed control-frankly flimsy you can identify, and then focus on the price-quality ratio that has a price-arrangement.
