Self-drilling/Self-tapping Fasteners: Self-drilling/self-tapping fasteners are installed without predrilling holes in the receiving member of the connection. The drilling function of the fastener must be completed prior to the lead threads of the fastener engaging the metal. This is normally accomplished by predrilling a clearance hole in the component being fastened to the receiving member. Clearance holes shall be 15/64 and 17/64 inch in diameter for No. 12 and 1/4 inch diameter fasteners, respectively. Fasteners must be installed with a 1800 to 2500 rpm electric screw driver incorporating a depth sensitive or torque-limiting nosepiece. Installed fasteners shall protrude through the attached members with the high-hardness drill point and lead threads beyond the attached members.