Общий каталог Widia 2017 - страница 1804

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Technical Information Definition of Screw Thread Tolerances It is generally recognised that, in mass production, it is impossible to reproduce in exact detail the theoretically perfect product as laid out on the drawing board. The allowed slight variation between the theoretically perfect product drawing and each unit of the actual product is called the tolerance. Allowance An intentional difference in correlated dimensions of mating parts. nut It is the minimum clearance or maximum interference between such parts. Angle of Thread major diameter The angle included between the flanks of the thread measured in an axial plane. pitch diameter lead angle Half Angle of Thread minor diameter The angle included between a flank of the thread and thenormal (90°) to the axis, measured in an axial plane.A-threadangle (whole) Lead of Thread _ The distance a screw thread advances axially in one turn. On a A single-thread screw, the lead and pitch are identical. On a double pitch thread, the lead is 2x pitch; on a triple thread, the lead is 3x pitch, etc. _ Major Diameter a – half angle The largest diameter of a straight-screw thread. Minor Diameter The smallest diameter of a straight-screw thread. screw Pitch The distance from a point on a screw thread to a corresponding point on the next thread measured parallel to the axis. The pitch in inches = 1 number of threads per inch Pitch Diameter pitch width of width of On a straight-screw thread, the diameter thread = space of an imaginary cylinder that would pass through the threads at such points as to make equal the width of the threads and the width of the spaces cut by the surface P.D. of the cylinder. Y100 widia.com Technical Information diameter of imaginary cylinder