A drilling machine is a device for drilling, countersinking or rubbing, either as a machine tool or as a powered hand tool. The actual tool is usually a drill, sometimes a reamer or a countersink clamped. The moldings made with the drill are bores. To put the drill in the required rotational movement, the drill has a torque generator, usually an electric motor, and pneumatic drives are common. In the time before industrial single- acting drives have been widely used in industry and craft by transmission drills (belt drive).
The electric hand drill built by Wilhelm Emil Fein in 1895 was one of the first power tools.
The device is manually held and guided while drilling. In addition to electric and pneumatic hand drills, there are also hand-driven devices such as the drilling winch.
For safe guidance of the drill machine at high torques, an additional handle can often be mounted just in front of the drill chuck for the other hand.
Often, a depth stop can also be mounted to limit the drilling depth. In the case of the machine shown in the top picture, it is possible to change between two gears with a changeover switch in order to drill at low or high speeds.
Many devices also have a step less power controller (often called “speed controller”), with which torque and speed can be influenced.
A percussion drill has a striking mechanism (usually disengage able), which exerts short-stroke axial impacts on the workpiece to be drilled via the drill head with a high impact rate. Many hand drills are – designed as impact drills – equipped with a switchable, integrated percussive device.
Impact drilling is almost always necessary for drilling in stone, masonry and concrete.
The impact mechanism almost always consists of a ratchet toothing on the drilling spindle. The effectiveness is achieved only by high pressure. Due to the system wear of the teeth occurs. For frequent drilling in concrete a hammer drill is more suitable.
Cordless drills (see also cordless tool) are cordless hand-held (impact) drills. Their applications are mostly light work in wood, plastic and metal. Most cordless drills have no hammer mechanism, so they are not suitable for drilling in hard rock or concrete.
The hammer drill is a drilling machine that specializes in drilling in stone and concrete as well as for chiseling.
The stroke rate is significantly smaller here than in the impact drill, but the impact energy is much higher.
In contrast to the impact drill, the blows are generated by a pneumatic hammer mechanism, which allows a higher impact energy. At the same time, the necessary holding force by the operator is lower than with a percussion drill of the same drilling capacity.
Bench Drills are single-spindle vertical drills that are fixed on work tables. The change of the speed is usually either step less or by folding a V-belt possible. Depending on the design, it is possible to additionally attach a rotary table to the column. The feed movement is predominantly manual via a lever.