A drilling and tapping machine includes a power head assembly supported at a vertical orientation, a parallelogram arm structure including a head support and an arm base, and an arm positioning assembly coupled with the head support and the arm base support for guiding corresponding movements of the head support and the arm base support so as to ensure a vertical trajectory of the power head assembly. The machine further includes a counterweight configuration to vertically move the power head assembly via a lever. The machine further includes an operational control assembly to selectively shift the power head assembly between a drilling operation and tapping operation. Therefore, the machine is suitable to make a hole with a diameter of 0.5 to 3 mm.