Bevel gear ordinary gear is the shape of a cylinder. The pitch angle of a gear is the angle between the face of the pitch surface and the axis. The most familiar kinds of bevel gears have pitch angles of less than 90 degrees and therefore are cone-shaped. This type of bevel gear is called external because the gear teeth point outward. The pitch surfaces of meshed external bevel gears are coaxial with the gear shafts; the apexes of the two surfaces are at the point of intersection of the shaft axes. Bevel gears that have pitch angles of greater than ninety
Nambu Type 90 Nambu Type 90 The Nambu Type 90 was a flare gun of Japanese origin and manufactured by Nambu. It was used by the Imperial Japanese Navy and came with two or three barrels. The Type 90 designation is from the last two digits of its year of adoption, which was 2590 (or 1930 AD) on the Japanese "Kōki" calendar. It first came with three barrels with just less than 6,000 were manufactured. The First Model (made in the early 1930s during peacetime) was highly polished and finished, while the Second Model (dating from the mid-1930s to the mid-1940s during wartime)