What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The contact surface between the existing chassis and the main board is generally not a horizontal plane due to processing reasons, especially the main board is prone to warping deformation. It will increase, resulting in deformation of the motherboard and poor memory contact, affecting normal use.
Flat gaskets are usually thin pieces of various shapes used to reduce friction, prevent leakage, isolate, prevent loosening, or distribute pressure. There are such components in many materials and structures. The existing flat washer has a simple structure design. After long-term use, the phenomenon of thinning of the thickness is likely to occur, which in turn leads to poor wear resistance of the flat washer.
The upper part of the T-bolt is a screw rod, and the bottom end is a T-shaped head. It is equipped with a sleeve with an anchoring plate. The fastening equipment is installed by the anchoring force between the T-shaped head and the anchoring plate. The appearance of the equipment after installation is shown in Figure 1, in which the figure composed of black lines is a component composed of T-bolts and integral sleeves. When constructing civil foundations, the sleeves should be pre-buried first, and the T-bolts will not be used until the equipment is installed. Anchor into the sleeve.
Code name and standard number of inch thread commonly used abroad Mark code name country and standard number Remarks BSW standard Wyeth coarse thread series, general purpose cylindrical thread British standard BS 84 inch thread with a profile angle of 55° BSF standard Wyeth fine thread series, General Purpose Cylindrical Thread Whit.S Additional Whit.S Optional Series, General Purpose Cylindrical Thread Whit Non-standard thread with Whitworth profile UN Uniform thread of constant pitch series American standard ANSI B1.1 inch thread with 60° profile angle, with Internal and external threads with standard profile (flat or rounded at random) UNC Coarse thread unified thread UNF fine thread unified thread UNEF superfine thread unified thread UNS① Special series unified thread UNR round The uniform thread profile angle of the arc root constant pitch series is 60° inch thread, UNR, UNRC, UNRF, UNREF, UNRS with arc root are only used for external thread without internal thread UNRC arc root coarse thread Series Unified Thread UNRF Circular Root Fine Thread Series Unified Thread UNREF Circular Root Ultra Fine Thread Series Unified Thread UNRS Circular Root Special Series Unified Thread NPT② Generally used for pipe thread American standard ANSI B1.20.1 Profile angle is 60° Inch Pipe Thread NPSC Pipe Fitting Straight Pipe NPTR Pilot Connection Tapered Pipe NPSM Mechanical Connection Straight Pipe NPSL Lock Nut Straight Pipe NPSH Hose Connection Straight Pipe NPTF Dry Seal Standard Tapered Pipe Thread American Standard ANSI B1.20.3 Type I PTF-SAE SHORT Dry Seal Short Taper Pipe Thread Type II NPSF Dry Seal Standard Fuel Oil Straight Pipe Internal Thread III Type NPS1 Dry Seal Standard General Straight Pipe Internal Thread IV Type ACME③ General Purpose Trapezoid Thread American standard ANSI B1.5 Inch drive thread with 29° profile angle ① Dimensions and tolerances All diameter and pitch combinations other than the standard series are calculated using the same formula as the standard series. ② my country's 60° conical pipe thread GB/T12716-1991 is equivalent to it. ③ACME thread includes two kinds of matching trapezoidal threads, general purpose and centering, of which the general purpose thread has the same performance as the trapezoidal thread specified in my country's standard GB/T5796-1986.
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