though they appear like a normal flathead style, they have got two holes in the groove that must be contacted for them to become properly driven into the material. You should utilize a Robertson’s little bit to travel it or utilize a special a person for the double-square for bigger torque software

A U-drive screw features a helical thread with the angle acute adequate to be pushed by a hammer or tension from an arbor press, and therefore contains a domed head without having means of turning it.[90] these are generally most frequently driven into plastics that has a pre-drilled pilot hole. See