| 摘要 |
A drill screw of the type suitable for fastening a sheet or plate to a lightweight steel frame member comprises a head portion, a threaded portion adjacent the head portion, a drill shaft portion adjacent the threaded portion, a large diameter drill portion adjacent the drill shaft portion, and a small diameter drill portion adjacent the large diameter drill portion. The small diameter drill portion has a smaller drill angle than the large diameter drill portion thus providing improved bite so that less thrusting force is required and the tendency to skid and drift is reduced.
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