| 摘要 |
<p>For use with screws having a slotted head and a central axial bore, a screwdriver blade is provided with a diametral blade tip and a central guide spigot extending axially beyond the tip and of greater cross-section than the top width. The spigot, which may be cylindrical or of square cross-section, serves to maintain the screw in co-axial relationship with the screwdriver and prevents the blade slipping out of the slot in use.</p> |
