Patent classifications
G01N2203/0053
Drilling needle, drilling resistance measuring device and use thereof for investigating properties of wood
A drilling needle includes a needle head at one end of a needle shank. The needle head has a flattened wedge portion with two wedge faces and a cutter portion with two cutting faces, which each adjoin one of the wedge faces and adjoin one another at a top edge that runs at a right angle to an axis of rotation. The needle head has on each side a relief face, which forms a cutting edge with each of the cutting faces. The cutting edge forms, with the respective other one of the cutting faces, a secondary edge that trails with respect to the direction of rotation. A relief angle, spanned by a virtual straight line through the cutting edge corner and a secondary edge and a plane that extends perpendicular to the top edge in the axis of rotation, lies in a range from 6 to 10.