tool base clearance
21Drill bit — For the fictional character, see Drill Bit (Transformers). For the cancelled skyscraper nicknamed Drill bit, see Chicago Spire. For the types used in drilling wells, see Well drilling. From top to bottom: Spade, lip and spur (brad point), masonry …
22Anthropology and Archaeology — ▪ 2009 Introduction Anthropology Among the key developments in 2008 in the field of physical anthropology was the discovery by a large interdisciplinary team of Spanish and American scientists in northern Spain of a partial mandible (lower… …
23Wrench — For other uses, see Wrench (disambiguation). A set of chrome vanadium metric wrenches, open at one end, box/ring at the other. This type is commonly known as a combination wrench. A wrench or spanner is a tool used to provide grip and mechanical… …
24Federal Bureau of Investigation — The Federal Bureau of Investigation (FBI) is the primary investigative arm of the United States Department of Justice (DOJ), serving as both a federal criminal investigative body and a domestic intelligence agency. At present, the FBI has… …
25Stone Age — the period in the history of humankind, preceding the Bronze Age and the Iron Age, and marked by the use of stone implements and weapons: subdivided into the Paleolithic, Mesolithic, and Neolithic periods. [1860 65] * * * First known period of… …
26Countersink — 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… …
27agriculture, origins of — Introduction the active production of useful plants or animals in ecosystems that have been created by people. Agriculture has often been conceptualized narrowly, in terms of specific combinations of activities and organisms wet rice production… …
28Valproic acid — Systematic (IUPAC) name 2 propylpentanoic …
29Mines Advisory Group — Type Non Governmental Organisation Industry Landmine relief Founded 1989 Headquarters …
30United States — a republic in the N Western Hemisphere comprising 48 conterminous states, the District of Columbia, and Alaska in North America, and Hawaii in the N Pacific. 267,954,767; conterminous United States, 3,022,387 sq. mi. (7,827,982 sq. km); with… …
