31. Then fold each end of the sticky tape up around the screw head and press these ends against the screwdriver blade. 32. Strictly speaking, the bearing area refers to the area of the screw head that directly bears on the part being fastened. 33. Spanners for Whitworth bolts are marked with the size of the bolt, not the distance across the flats of the screw head . 34. _When removing screws, you will inevitably run into a different type of screw head requiring, say, a seven-sided carbon steel driver bit. 35. If you use solid brass screws, you don't have to countersink them; the exposed screw heads become part of the bookcase's design. 36. Compatible screw heads are usually identifiable by a single depressed dot or an " X " to one side of the cross slot. 37. I suggest your son have the plasterboard seams taped and covered with joint compound ( also covering the nail or screw heads ). 38. This approach creates a set of graduated slotted screwdrivers that fit a particular screw for a tighter engagement and reduce screw head deformation. 39. Can someone say what type of screw head socket ( or bolt head socket ) is most resistant to rounding-preferable from personal experience? 40. This feature can be identified as a small screw head on the barrel bridge with the word " patent " next to it.
