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Glossary of Terms D A|B|C|D|E|F|G|H|I|J|K|L|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z D & T - drill and tap DED - dedendum DP - diametral pitch Dedendum (DED) - is the radial or perpendicular distance between the pitch circle and the bottom of the gullet. Diametral Pitch (DP) - is the ratio of the number of teeth to the number of inches in the pitch diameter. There is a fixed relation between diametral pitch (DP) and circular pitch (CP), namely CP = pi/DP. Double-Duty Extended Pitch Sprocket - This describes Linn Gear Co. standard, stock Extended Pitch sprockets. With these sprockets one pitch of the chain spans across two teeth. When run on a sprocket with an odd number of teeth the chain rollers will alternate gullets on each revolution of the sprocket. The rollers will cycle through all of the sprocket's gullets every two revolutions of the sprocket. When an extended pitch chain is run on a sprocket with an even number of teeth the chain rollers will use only one set of the sprocket's gullets until the chain is manually reset to the second set. Two terms are used in describing the number of teeth on a double-duty extended pitch sprocket, Actual Number of Teeth and Effective Number of Teeth. The Actual Number of Teeth is exactly that. If you count the number of tooth projections on the perimeter of the sprocket you will get the Actual Number of Teeth. The Effective Number of Teeth is one half of the Actual and refers to the number of sprocket gullets utilized in one revolution of the sprocket. Single-duty Extended Pitch sprockets are available made-to-order. Double-Single Sprocket - a double strand sprocket wide enough to operate with two single chains. These may be made up of two like sprockets or as a `Compound Double-Single' which is a combination of two sprockets of different pitch and/or number of teeth. |