What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
High-strength hexagon head bolt combination screws for steel structures, mainly used in railway and highway bridges, boiler steel structures, industrial plants, high-rise civil buildings, tower and mast structures, hoisting machinery and their steel structures need to use friction-type high-strength bolt combinations for screws. It is characterized by an extra dodecagon at the end of the bolt, also known as the bolt. When installing, a special electric wrench must be used, which has two socket heads up and down, one is set on the hexagonal body of the nut, and the other is set on the decagon body of the outer hexagon screw. When tightening, apply a clockwise force to the nut, and apply an equal counterclockwise force to the dodecagon body of the bolt, so that the connecting neck between the end of the outer hexagon screw and the dodecagon body is subjected to torsion shearing until the neck is sheared. So far, the installation has come to an end. This torsion shear type high-strength outer hexagon screw is a one-time-use screw and generally cannot be removed after installation.
The positioning pin is a pin designed to accurately position the two adjacent parts of the mold in a mold composed of two or more parts. It can be seen that the positioning pin plays a positioning role, and the mold must be accurately synchronized when it is closed. product, and the positioning pin can make the upper and lower molds play a role in accurate positioning. In the mold design and manufacture of Yueluo, the positioning pin is one of the most common parts. Since it is only used for positioning between parts, few people will pay too much attention to it. In the cold stamping process of Yueluo, the dimensional accuracy of the blanking parts depends on the size of the working part of the punch and the concave die, and the dimensional difference between them constitutes the blanking die gap. Gap is an important process parameter for die design, and its size has a great influence on the quality of the section of the blanking part, the blanking force, and the life of the die. If the gap is too large, punching burrs will appear in punching; if the gap is too small, secondary cracks will occur in the section and extrusion burrs will appear, which will make the quality of the section after punching unsatisfactory, and a reasonable gap will not only help the punching section. The improvement of quality also contributes to the improvement of the lifespan of the 12-year-old utensils.
GB/T3103.3-2000 Fastener Tolerance Flat Washers 2 GB/T5286-2001 General Scheme of Flat Washers for Bolts, Screws and Nuts 3 GB/T9074.1-2002 Bolts or Screws and Flat Washers Assemblies 4 GB/T9074. 18-2002 Self-tapping screws and flat washers assemblies 5 GB/T 95-2002 Flat washers C grade 6 GB/T96.1-2002 Large washers A grade 7 GB/T96.2-2002 Large washers C grade 8 GB/T97. 1-2002 Flat washer Class A 9 GB/T97.2-2002 Flat washer chamfered Class A 10 GB/T97.4-2002 Flat washer for screw and washer assemblies 11 GB/T97.5-2002 Flat washer Self-tapping screws and washers assemblies 12 GB/T848-2002 Small washers Class A 13 GB/T5287-2002 Extra large washers Class C 14 GB/T4678.13-2003 Die-casting mold parts Part 13: Push plate washers 15 GB/T4605 -2003 Rolling bearing thrust needle roller and cage assemblies and thrust washers 16 GB/T97.3-2000 Flat washers for pins 17 GB/T18230.5-2000 Flat washers for bolted structures quenched and tempered 18 GB/T9074.5 -2004 Cross recessed small pan head screw and flat washer assembly 19 GB/T9074.20-2004 Cross recessed hexagon head tapping screw and flat washer assembly 20 GB/T3762-1983 Sharp angle sealing washer for ferrule type pipe joint 21 GB/T1231-2006 Specifications for high-strength large hexagon head bolts, large hexagon nuts and washers for steel structures 24 GB/T5649-2008 Lock nuts and washers for pipe joints and washers 27 GB/T10447-2008 Elements and tolerances of semicircular thrust washers for sliding bearings 28 GB/T94.1-2008 Specifications for elastic washers Spring washers 29 GB/T10446-2008 Dimensions and tolerances for full circle thrust washers for sliding bearings 30 GB/ T93-1987 standard spring washer 31 GB/T94.2-1987 elastic washer technical conditions toothed, serrated lock washer 32 GB/T98-1988 stop washer technical conditions 33 GB/T849-1988 spherical washer 34 GB/T850- 1988 Conical Washer 35 GB/T851-1988 Split Washer 36 GB/T852 -1988 Square bevel washer for I-beam 37 GB/T853-1988 Square bevel washer for channel steel 38 GB/T854-1988 Single-ear stop washer 39 GB/T7244-1987 Heavy-duty spring washer 40 GB/T855-1988 Double-ear stop Dynamic washer 41 GB/T7245-1987 Saddle spring washer 42 GB/T7246-1987 Wave spring washer 43 GB/T856-1988 Outer tongue stop washer 44 GB/T858-1988 Stop washer for round nut 45 GB/T859-1987 Light spring washer 46 GB/T860-1987 Saddle elastic washer 47 GB/T861.1-1987 Internal tooth lock washer 48 GB/T861.2-1987 Internal serrated lock washer 49 GB/T862.1-1987 External tooth lock 50 GB/T862.2-1987 External Serrated Lock Washers 51 GB/T955-1987 Wave Elastic Washers 52 GB/T27938-2011 Sliding Bearing Thrust Washers Failure Damage Terms, Appearance Features and Reasons 53 GB/T956.1- 1987 Conical lock washer 54 GB/T956.2-1987 Conical serrated lock washer 55 GB/T28697-2012 Rolling bearing self-aligning thrust ball bearing and self-aligning seat washer Dimensions 56 GB/T9074.2-1988 Cross groove disc Head screw and male serrated lock washer assembly 57 GB/T9074.3-1988 Cross recessed pan head screw and spring washer assembly 58 GB/T9074.4-1988 Cross recessed pan head screw, spring washer and flat washer assembly 59 GB /T9074.7-1988 Cross recessed small pan head screw and spring washer assembly 60 GB/T9074.8-1988 Cross recessed small pan head screw and spring washer and flat washer assembly 61 GB/T9074.9-1988 Cross recessed countersunk Head screw and conical lock washer assembly 62 GB/T9074.10-1988 Cross recessed countersunk head screw and conical lock washer assembly 63 GB/T9074.11-1988 Cross recessed hexagon head bolt and flat washer assembly Parts 64 GB/T9074.12-1988 Cross recessed hexagon head bolt and spring washer assembly 65 GB/T9074.13-1988 Cross recessed hexagon head bolt, spring washer and flat washer assembly 66 GB/T9074.15- 1988 Hexagon head bolt and spring washer assembly 67 GB/T9074.16-1988 Hexagon head bolt and serrated lock washer assembly 68 GB/T9074.17-1988 Hexagon head bolt, spring washer and flat washer assembly 69 GB/T9074 .26-1988 Spring Washers for Assemblies 70 GB/T9074.27-1988 External Serrated Lock Washers for Assemblies 71 GB/T9074.28-1988 Conical Lock Washers for Assemblies 72 GB/T1030-1988 Inner Spherical Washers[1]
The combination screw is actually a kind of screw, but it is special. It is generally a three-component or a two-component, but at least it can be called a combination screw. The main difference from ordinary screws is that they are equipped with one more spring washer or one more flat washer than ordinary screws. This is the main difference between the appearance of combination screws and ordinary screws. In addition to the obvious difference in appearance between combination screws and ordinary screws, the main difference is the difference in mechanical properties and uses. The combination screw is a three-component or two-component with a flat washer. Of course, it is equipped with a flat washer by an ordinary screw. When the spring flat pad is attached, the spring flat pad will not fall off. Fastened to form an assembly. In terms of mechanical performance, the combination screw is composed of three accessories, and in terms of performance, three fasteners must be used together. The mechanical properties of the combined screw are stronger when used. More convenient, the biggest advantage of the combined screw is that the production line can be operated conveniently and quickly, and the work efficiency can be improved. The difference between the use of combination screws and ordinary screws is mainly in the breadth of use. The use of ordinary screws is more extensive than that of combination screws. Basically, ordinary screws are used in industrial products, and combination screws! It is only useful for specific product materials. When the screw needs to be used with a spring washer and a flat washer, the combination screw can be used at this time.
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