Control method and portable power tool

A control method for a bore-chiseling portable power tool for machining a substrate by a drill bit, wherein the portable power tool has a tool holder for holding the drill bit on a work axis, a rotary drive for rotating the tool holder about the work axis, and a striking mechanism for striking the drill bit, comprising the steps of:

• superimposing a periodic striking on the drill bit at an impact rate and a rotating of the tool holder at a rotational speed in a rotational direction;
• identifying a material of the substrate being machined by the drill bit by a sensor;
• adjusting the rotational speed and the rotational direction to a first rotational speed and a first rotational direction when the material is an iron-based material;
• and
• adjusting the rotational speed and the rotational direction to a second rotational speed and a second rotational direction when the material is a mineral material;
• wherein the first rotational speed is less than the second rotational speed and the first rotational direction is counter-clockwise and the second rotational direction is clockwise.