Grub screw with cruciform slotted end - has hole at intersection of slots for entry of cruciform screwdriver point

摘要

The grub screw is provided at one end with two mutually perpendicular slots (16) for application by a flat-bladed screwdriver. At the intersection of the slots the screw has a blind hole (14) extending to a depth greater than that of the groove. This enables a cruciform screwdriver to be used as an alternative. Pref. the hole has a depth twice that of the slots and has a diameter about half the outside diameter of the screw. The screw may be made by drilling the hole and subsequently sawing or milling the slots.