Common types of threaded drilling screws: screw thread fit quality: (inch thread fit quality inch) inch thread fit
Is between the screw-thread loose or tight tie between the screw-thread size thread loose or tight, tie ranks are acting on the inner and outer thread deviations and tolerances provided combinations. Provisions of deviations and tolerances used in internal and external thread combination. For unified inch screw threads, external threads there are three threads: and for unified inch screw threads, external threads there are three threads: 1 a and 2 a and 3 a-class, internal thread there are three levels: 1 b, 2B and 3 b-class, all-level thread has three levels: level and a clearance fit. Higher grade number, coupled with tighter. Inch thread, a clearance fit. Higher grade number, coupled with tighter. Inch thread, deviation deviation of provision 1 of grade a and grade zero difference only and 2 a, 3 a-class deviation is zero, and deviation is zero and 1 of 2 a-class a and scale of deviation are equal. Scale of deviation are equal. The smaller the grade number, the greater the tolerance, as shown in the figure: the smaller the grade number, the greater the tolerance, as shown in the figure: fastener professional 15 threads with the firmware level: (inch thread fit inch) inch
Level 1, 1 a and 1 b, very loose tolerances, it is suitable for internal and external thread, and very loose tolerances grade, tolerance fit. Tolerance fit.
Level 2, 2 a and 2 b, is a British series mechanical fasteners provided the most common, and the level of thread tolerance class. Thread tolerance class.
3, 3 a and 3 b-class, spin forming tight fit, suitable for tight tolerances, and vortex to form the most fit, tighten fasteners, for safety critical designs. Tighten fasteners, for safety critical designs. 4, external thread, 1 a and 2 a-class a tolerances, 3 a-class a tolerances, level, external thread, and class a tolerances are not. 1 a-level tolerance 50% larger than the tolerances, no larger than 3 a-class. Tolerances are larger than the tolerance class 2 a, level greater 75% tolerance class larger than the tolerances for larger internal threads, tolerance 30% larger than the tolerance. 2A 1 class b tolerances tolerances, internal thread, 2 class b tolerances tolerances. Level than level 2 class b 50%, 75% larger than the 3 b-level. Great, great. Fastener fastener professional 16 thread tolerances and limits of size reference: JIS b 0210-1973 fastener