The tolerance class H11 is a range of 0.11 The basic deviation is 0 for the upper deviation; the lower deviation is -0.11; this 0.11 is obtained by looking up the table.
The tolerance is a range calculated as: upper deviation - lower deviation.
Tolerance grade is to determine the degree of accuracy of the size of the level, the national standard is divided into 20 grades, from IT01, IT0, IT1, IT2 to IT18, the larger the number, the lower the tolerance level (machining accuracy), the size of the permissible range of changes (tolerance values) the larger, the less difficult to process.
Extended information:
Tolerance Grade
Applications and Examples
IT8
It belongs to the medium precision in mechanical manufacturing, and belongs to the higher precision range in the manufacturing of instruments, gauges and clocks due to the smaller basic dimensions, and is in the range of higher precision in agricultural machinery, textile machinery, printing and dyeing machinery, bicycles, Sewing machine, medical equipment in a wide range of applications.
For example, the inspection of the IT16 level workpiece with the gauge, bearing housing bushings along the width of the size of the fit, the watch across the tooth axis, pawl dial wheel, etc., and the clamping plate with the radio instrumentation in the general fit, and so on.
IT9
Application conditions are similar to IT8, but the precision is lower than IT8 when used, than the old national standard 4 precision tolerance value is slightly larger.
For example, machine tools and holes in the outer diameter of the bushing, manipulation of parts and shafts, idling pulleys and shafts, shafts and bearings of the manipulation system, textile machinery, printing and dyeing machinery in the general with the parts, the engine in the oil pump body holes, the inner hole of the valve guides, flywheel and flywheel bushing with the general size of automation instrumentation, and so on.
IT10
Application conditions are similar to IT9, but the requirements of the accuracy is lower than the IT9 when used, equivalent to the old national standard of precision tolerance level 5.
For example, electronic instruments, instruments in the bracket with the navigation instrument in the insulating bushing hole and the converging ring bushing shaft, typewriter riveted parts with the size, the basic size of the watch is less than 18 mm when the general requirements of the size of the unannotated tolerance, and greater than 18 mm requires a higher unannotated tolerance dimensions, the engine in the oil seal retaining ring holes with the crankshaft pulley hub with the size, and so on.
IT11
Widely used in the clearance is large, and there is a significant change will not cause danger of the occasion, can also be used to cooperate with the lower precision, assembly allows a larger gap, the equivalent of the old national standard of the 6 level of precision tolerances.
For example, machine tool flange stops and holes, slider and slip gears, grooves, etc.; agricultural machinery, locomotive carcase parts and stamping processing of the parts with the parts, watch manufacturing in the unimportant parts, watch manufacturing tools and equipment in the unnotated tolerance of the dimensions of the textile machinery in the rougher activities with the dyeing and printing machinery in the requirements of the lower with the dimensions, and so on.
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