square countersunk head bolt
1patch bolt — noun : a bolt used in the repair of boilers and of ships with hulls of steel plate that has a countersunk head with a square knob which is twisted off when the bolt is screwed home …
2Screw — This article is about the fastener. For other uses, see Screw (disambiguation). Screws come in a variety of shapes and sizes for different purposes. U.S. quarter coin (diameter 24 mm) shown for scale. A screw, or bolt, is a type of fastener… …
3Countersink — A countersink is a conical hole cut into a manufactured object, or the cutter used to cut such a hole. A common usage is to allow the head of a countersunk bolt or screw, when placed in the hole, to sit flush with or below the surface of the… …
4List of screw drives — Contents 1 Common types 1.1 External types 1.1.1 Square 1.1.2 Hex …
5Washer (hardware) — Assorted washers: flat, split, star and insulated A washer is a thin plate (typically disk shaped) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are… …
