| 摘要 |
<p>A self-drilling and thread forming fastener for fastening a first softer workpiece, such as wood, to a second harder workpiece, such as metal, is described The fastener features wings (87, 88) of improved configuration including positive angle of attack, positive cutting edge relief angles, teardrop-like crescent shape cross section and knife-like cutting edge which exhibit faster drill times through wood.</p> |
