Abstract: An improved drafting instrument is provided for scribing small dots on a drafting medium comprising a substrate provided with a removable surface coating. The drafting instrument includes a drive motor and rotatable cutter which are slidably mounted as a unit for vertical movement toward and away from the drafting medium. A manually operable actuator is provided for moving the drive motor downward to bring the cutter into engagement with the surface coating of the drafting medium. A control switch responds to downward movement of the drive motor and cutter by a predetermined distance for automatically actuating the drive motor before the cutter is moved into engagement with the drafting medium. The drafting instrument includes an adjustable depth limit feature to control the depth of penetration of the cutter into the surface coating of the drafting medium. The operation of the drive motor and rotation of the cutter are automatically terminated when manual pressure on the actuator is released.