The invention concerns a drilling device (1) and a method for drilling holes in a stack of material (100). The drilling device is provided with clamping means (23, 26) for clamping the material, a hollow drill (10) with an internal channel and a drive (3) for the hollow drill. The drilling device is further provided with connecting means (4) for cooling means, that are arranged for conducting gas through the internal channel, and suction means (51) for suctioning drilling debris. The drilling shaft is provided with a cut out, that runs in longitudinal direction along the drill shaft and forms a discharge channel for the drilling debris.

The invention also concerns a machine for machining and assembling window coverings, such as pleated blinds, comprising one or more drilling devices according to the invention.

A cutting section (11) which is connectable to a drill shaft section via a releasable connecting device. The cutting section includes a first closed tubular element (14) which is in the form of a first hollow cylinder having a first waved, trapezoidal or zigzag-shaped cross-sectional area, a second closed tubular element (15) which is in the form of a second hollow cylinder having a circular ring-shaped cross-sectional area, and one or more drill segments (16) which are connected to the first closed tubular element (14).