Chipboard ScrewsHeat Treated Case Hardened to Prevent Snapping 40 Degree Thread Angle, 25 Degree Point Angle Zinc, Yellow Zinc, Brass or Black Oxide available PATTA self-drilling Chipboard screws have a coarse thread and fine shank to provide maximum grip and minimum strip out into chipboard, MDF board and soft timbers. The head has ribs molded around the countersunk head which help remove the chipboard particles when countersinking. How to Use 1. Measure the total thickness of the materials to be fastened. 2. Choose a screw long enough to provide approx. 20mm of thread embedment into the chipboard or wood being fastened to. 3. Fit a #2 Phillips drive bit to a power screwdriver set to low speed, approx. 1000rpm. normal size M3.0 M3.5 M4.0 M4.5 M5.0 M6.0 thread diameter min. 2.8 3.3 3.75 4.25 4.7 5.7 max. 3 3.5 4 4.5 5 6 head diameter min.. 5.6 6.6 7.5 8.5 9.5 11.5 max. 6 7 8 9 10 12 pitch 1.35 1.6 1.8 2 2.2 2.6 head height max. 1.9 2.1 2.5 2.7 3 3.6 shank max. 1.6 1.8 2 2.2 2.5 3 recess no. 1 2 2 2 2 3 recess depth min. 1.6 1.6 2.05 2.6 3 3 max. 2 2.1 2.5 3.1 3.45 3.45