What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Copper nuts, also known as embedded nuts and embedded copper nuts or plastic embedded nuts, are divided into hot melt copper nuts, hot pressed copper nuts, embedded copper nuts and ultrasonic copper nuts according to different methods of use. This product is widely used in mobile phones. Shell / Pen meter shell / injection molding / insert of plastic parts, used as an internal thread. Generally embossed on the outer circle. To prevent sliding.
Inch Screws C-1: Thread Code: The denominator is marked as 8, and then the numerator is directly called the number. Ex: 1/8 x 0.50 –PPB: 1 Thread screw x 0.50” long, PPB Ex: 5/16 x 0.50 –PPB = 2.5/8 x 0.50-PPB : 2 ½ inch screw x 0.50” long, PPB Ex: 5/32 x 0.50 –PPB =1.25/8 x 0.50-PPB: 1 ½ ½ inch screw x 0.50” long , PPB Ex: 1/4 x 0.50-PPB= 2/8 x 0.50-PPB: 2-point screw x 0.50” long, PPB Note: Coarse or fine pitch is sometimes indicated. UNF: Fine pitch: more commonly used in the electronics industry UNC: Coarse Thread: More commonly used for heavy machinery construction. Ex: 3/8 x 0.50, UNF –PPB: 3 point fine thread screw x 0.50” long, PPB. C-2: Length Code: In inches, must be multiplied by 25.40 is converted to mm. Measured with a buckle gauge, it is a metric thread when it matches the metric thread, and an inch thread when it matches the inch thread. You can also use a caliper to measure the outer diameter and pitch of the thread. The outer diameter of the metric thread is in millimeters, Such as 6, 8, 10, 12, 18, 20 mm, etc., the pitch is also in millimeters, such as 0.5, 0.75, 1, 1.5, 2, 3, etc. The outer diameter of the imperial thread is in inches, (per inch Equal to 25.4 mm) such as 3/16, 5/8, 1/4, 1/2, etc. Therefore, the reading of the outer diameter with a metric caliper often has irregular decimals. The inch pitch is expressed by how many teeth per inch. Set the caliper at 25.4 mm, align one caliper tip with the thread cusp, and the other caliper tip, if aligned with the thread cusp, is an inch thread, and if the thread cusp is not aligned, it should be a metric thread. The tip is printed on the white chalk. The chalk is clear and easy to measure. To measure the metric pitch, you should measure a length, such as 10, 15, 20, millimeters, etc., count how many teeth are included, and calculate the pitch in inches. The specified thread specification is inch thread, such as: G1. Metric threads are specified in metric units of millimeters. Such as: M30. The imperial system is determined by how many teeth there are in one inch (2.54 cm), generally a 55-degree angle. The metric system is the pitch determined by the distance between the two tooth tips, usually a 60-degree angle anchor screw: tighten the machine, etc. Screws for use on the ground. Also called anchor bolts. The difference between British and American screws is difficult to distinguish visually. The difference between British and American screws is that the rolling angle of British screws is 55 degrees, while the rolling angle of American screws is 60 degrees. These two standard screws are used in most screws. It can be used in general, but 1/2 size screws are not allowed, because the standard thread of inch 1/2 is 1/2-12 teeth, while the American system is 1/2-13 teeth.
Standard introduction Standard code name Material coating GB/T65-2000 slotted cylindrical head screw steel, stainless steel galvanized passivated or untreated GB/T67-2000 slotted pan head screw steel, stainless steel galvanized passivated or not Treated GB/T68-2000 slotted countersunk head screw steel, stainless steel galvanized passivated or untreated GB/T70.1-2008 hexagon socket head screw steel, stainless steel galvanized passivated or untreated GB/T70 .2-2008 Hexagon socket head screw steel, stainless steel galvanized passivated or untreated GB/T70.3-2000 Hexagon socket head countersunk head screw steel, stainless steel galvanized passivated or untreated GB/T71-1985 Open Slotted taper end set screw steel, stainless steel galvanized passivated or untreated GB/T73-1985 slotted flat end set screw steel, stainless steel galvanized passivated or untreated GB/T74-1985 slotted concave end set screw Screw steel, stainless steel galvanized passivated or untreated GB/T75-1985 slotted long cylindrical end set screw steel, stainless steel galvanized passivated or untreated GB/T77-2000 hexagon socket flat end set screw steel, stainless steel Galvanized passivated or untreated GB/T78-2007 Hexagon socket set screw steel, stainless steel galvanized passivated or untreated GB/T79- 2000 Hexagon socket set screw steel, stainless steel galvanized passivated Or untreated GB/T80-2007 Hexagon socket set screw steel, stainless steel galvanized passivated or untreated GB/T818-2000 Cross recessed pan head screw steel, stainless steel galvanized passivated or untreated GB/ T819.1- 2000 Cross recessed countersunk head screw steel 4.8 grade steel galvanized passivation GB/T819.2- 1997 Cross recessed countersunk head screw steel, stainless steel A2-70, non-ferrous metal CU2 or CU3 steel, stainless steel or non-ferrous metal plated Zinc passivated or untreated GB/T820- 2000 Cross recessed half countersunk head screw steel, stainless steel galvanized passivated or untreated GB/T822- 2000 Cross recessed cylinder head screw steel, stainless steel galvanized passivated or untreated Treated GB/T823-1988 cross recessed small pan head screw steel, stainless steel galvanized passivated or untreated GB/T833-1988 slotted large cylindrical head screw steel, stainless steel galvanized passivated or untreated GB/ T837- 1988 Slotted pan head non-prolapse screw steel, stainless steel galvanized passivated or untreated GB/T838- 1988 Hexagon head non-prolapse screw steel, stainless steel galvanized passivated or untreated GB/T2671.1- 2004 Hexagon socket head low cylindrical head screw GB/T2671.2-2004 Hexagon socket head screw GB/T2672-2004 Hexagon socket head pan head screw steel galvanized passivation GB/T2673-1986 Hexagon socket countersunk head screw steel plated Zinc passivation GB/T13806.1-1992 Fasteners for precision machinery ten Slotted Screws Steel, Copper: H68 or HP59-1 Zinc Passivated or Untreated
Screws and bolts are common connecting fasteners. The diameter of the thread is as small as less than one millimeter and as large as several hundred millimeters or even larger. The vast majority of threaded connections are pre-tightened during assembly in order to enhance the rigidity, tightness, anti-loosening ability of the connection and prevent the sliding of the bolted connection under lateral load. The pre-tightening force is determined according to the force of the bolt group and the working requirements of the connection. For important threaded connections, the preload must be measured and controlled.
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