BS 4621:2010 pdf download – Aerospace series — Inserts, MJ threads, self-locking, self-broaching keys — Technical specifications 3.2.11 limiting qualityLQ10 in a sampling plan, quality limit which corresponds to a specified 10 % probability of acceptance NOTE1 lt is the limiting lot quality characteristic that the consumer is willing to accept with a low probability that a lot ofthis quality would occur. NOTE2 For the purposes of this standard,the limiting quality quoted in Table 4 corresponds to a probability ofacceptance of 10 %. 3.2.12 acceptance quality limitAQL quality limit which in a sampling plan corresponds to a specified but relatively high probability of acceptanceNOTE lt is the maximum percent defective (or the maximum number of defects per hundred units) that, for purposesof sampling inspection, can be considered satisfactory as a process average. 3.2.13 finished insert insert ready for use, inclusive of any possible treatments and/or surface coatings, as specified in the definitiondocument 3.2.14 definition document document specifying all the requirements for finished inserts 3.2.15 self-locking torque ttorque to be applied to the associated bolt to maintain movement of rotation in relation to the part, theassembly being under no axial load and the insert locking zone being completely engaged with the bolt(minimum protrusion of two pitches, including the end chamfer) 3.2.16 seating torque tightening torque to be applied to the insert or bolt to introduce or to increase the axial load in the assembly 3.2.17 unseating torque untightening torque to be applied to the insert or bolt to reduce or remove the axial load in the assembly 3.2.18 breakaway torque torque required to start unscrewing the insert or the bolt from the associated part, with the insert lockingdevice still fully engaged on the bolt, but after the axial load in the assembly has been removed by unscrewinghalf a turn followed by a halt in rotational movement 4.1QualificationEN 9133. Qualification inspections and tests (requirements, methods, numbers of inserts with self-broaching keys) arespecified in Table 1.They shall be carried out on: —each type and diameter of inserts; —39 inserts selected from a single batch by simple random sampling. The test programme may possibly be reduced, or the qualification be granted without inspection or testing. Any such decision shall be based on the results obtained on similar types and diameters of inserts providedthat the design and manufacturing conditions are identical. Table 2 indicates the allocation of insert samples for the inspections and tests. 4.2Acceptance...
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