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The assessments were introduced following the introduction of a National Curriculum to schools in England and Wales under the Education Reform Act 1988.As the curriculum was gradually rolled out from 1989, statutory assessments were introduced between 1991 and 1995, with those in Key Stage 1 first, following by Key Stages 2 and 3 respectively as each cohort completed a full key stage. [2]
ISO 898 is an international standard that defines mechanical and physical properties for metric fasteners.This standard is the origin for other standards that define properties for similar metric fasteners, such as SAE J1199 and ASTM F568M. [1]
The applied torque causes the bolt to "climb" the thread causing a tensioning of the bolt and an equivalent compression in the components being fastened by the bolt. The preload developed in a bolt is due to the applied torque and is a function of the bolt diameter, the geometry of the threads, and the coefficients of friction that exist in the ...
Two spanners, both nominal size 5 ⁄ 8 in, with a diagram superimposed to show the logic that allows them both to be nominal size 5 ⁄ 8 in when their actual sizes are clearly different (across-flats distance vs screw diameter). The across-flats definition is the common standard today, and has been for many decades.
ASTM A325 is an ASTM International standard for heavy hex structural bolts, titled Standard Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength. It defines mechanical properties for bolts that range from 1 ⁄ 2 to 1 + 1 ⁄ 2 inches (13 to 38 mm) in diameter. [1]
The torque applied to the fastener must be determined such that it does not contribute to a service condition where the fastener enters a low-cycle fatigue regime. In general, the use of torque-to-yield fasteners is deprecated except in cases where the materials and structures comprising the entire assembly are certified to be within tolerances ...
Hanger bolt - Bolt that has no head, machine threaded body followed by a wood threaded screw tip. Allow nuts to be attached to what is really a screw. Hex bolt - Bolt with a hexagonal head and threaded shank. Section immediately under head may be unthreaded for fastening thicker materials. J bolt - Bolt shaped like the letter J, used for tie downs.
This standard defines property classes, the metric equivalent of a screw grade, that are almost identical to those defined by ISO 898-1, [2] except for the addition of the 8.8.3 and 10.9.3 classes. These two additional standards are fasteners that have the same mechanical properties as their base property class (i.e. 8.8 and 10.9), but are made ...