A drive train for supplying power to a power tool may include, a motor, a motor shaft, a rotational coupling mechanism connected to the motor shaft, and a drive shaft connected to the rotational coupling mechanism that forms the shape of a “U.” A pair of enmeshed bevel gears transfers the motion from the motor shaft to an orthogonal tool bit. The drive train may also include a hammering device that transfers a rotational impacting motion to the tool bit. A hand power tool for driving a screw may include a tool shell with an integrally formed vertical handle, a rotational recess formed into the tool shell opposite the handle, and a tool chuck within the rotational recess that drives a screw. The tool may incorporate the drive train as described above. The tool may include a mechanism for locking the tool chuck in a particular position.