Classification of screws
Screws can be divided into machine screws, self-tapping screws, drilling screws, wallboard screws, fiberboard screws, wood screws, hexagonal wood screws, loose screws, combined screws, miniature screws, furniture screws and electronic screws.
International specification for screws
There are two versions of screws in international standards, one is GB70-76,76, and the other is GB70-85,85.
In M8 series hexagon socket products, the international standard diameter of GB70-76 is12.5mm.. The international standard specification of GB70-85 is13.27mm..
M 10 series hexagon socket products, the international standard round head diameter of GB70-76 is 15mm, and the international specification of GB70-85 is16.27 mm.
M 12 series hexagon socket, the diameter of round head in GB70-76 international standard is 18mm, and the international specification in GB70-85 is18.27mm..
In addition, the international standard round head diameters of M 16 and M20 series hexagon socket GB70-76 are 24MM and 30MM respectively. The international specifications of GB70-85 are 24.33MM and 30.33MM respectively.
China standard for screws.
The commonly used screw standards in China are: GB52, GB6 170, GB6 172 and DIN934.
In M8 nut series, the opposite sides of DIN934, GB6 170 and GB6 172 are all 13MM, and the opposite side of GB52 is 14MM.
For nuts with M 10, the opposite sides of DIN934 and GB52 are 17MM, and the opposite sides of GB6 170 and GB6 172 are 16MM.
For the nut of M 12, the opposite sides of DIN934 and GB52 are 19MM, and the opposite sides of GB6 170 and GB6 172 are 18MM.
For the nut of M 14, the opposite sides of DIN934 and GB52 are 22MM, and the opposite sides of GB6 170 and GB6 172 are 21mm..
M22 nut, the opposite sides of DIN934 and GB52 are 32MM, and the opposite sides of GB6 170 and GB6 172 are 34MM.
Description method of specifications and names of combined screws
① Nominal thread outer diameter: divided into metric system and English system.
Metric thread? →? The commonly used specification is 2; 2.3; ? 2.5; ? 2.6; ? 2.9; 3? ; 3. 1; 3.5; 4; ? 4.2; 4.5; 4.8; ? 5; ? 6? ;
8; 10; 12; 14; 16; 20? . The unit is mm (millimeter).
English thread? → The common specification is 2 #; 4#; 6#; 8#; 10#; 12#; 1/4; 7/32; 5/ 16; 3/8; 1/2; 9/ 16; ? 3/4? . single
Bite in? (inches).
② Number of teeth/pitch:
What is the definition of the number of teeth? →? Number of tooth lines included in one inch (25.4 mm) length.
Definition of pitch? →? The distance between two adjacent threads.
Number of teeth and pitch conversion? →? Pitch = 1 inch/number of teeth
③ Nominal length: For the length measurement method of screw assembly, please refer to "Our Common Methods for Measuring Screw Length", and the nail length is not affected by the washer.
Ring; Nominal length is divided into metric system and English system.
Metric nominal length? →? Common values are 5, 6, 6.5, 7, 8, 9, 9.5, 10,1,12, 13, 14,/kloc-0. 18、 19、? 20、
2 1、25、28、30、3 1、32、35、40、42、45、50、55、60、65、? 70、75、80、? 85、90、95、 100、 1 10、 120。 The unit is mm (millimeter).
English nominal length? →? Common values are 1/4,5/16,3/8,7/16,1/2,5/8,3/4,1,? 2、3; Unit? Inches? )。
4 head type? : Use letters to indicate the type of head type. Please refer to "Classification of Screw Head Types".
⑤ Tooth type/tail type? :? Please refer to the previous "Classification of Common Screw Tooth Types/Tails" for the types of tooth types/tails indicated by letters.
⑥ Combination code: Reference? The type of screw assembly commonly used in our company is "= 1, =2, =3".
⑦ Slot type: Refer to the above "Classification of Slot Types of Common Screws in Our Company". There is no need to mark cross grooves or no grooves (such as hexagon-head screws) here. What else is there? cell type
It needs to be explained in words.
8 Special mark:? Generally, labeling is not required. When expressing its characteristics, describe it in words at this position.
For example, the specification name of the screw is described as "6-1.0x16tm =1φ12.5 string of plastic washers", which means that "6" is the nominal diameter of the thread;
"1.0 is the pitch; ? "16" is the nominal length of the screw, "t" means that its head shape is oblate, and "m" means its tooth type? /tail type
It is a mechanical tooth; "= 1" is a combination generation? Code; ""means that its groove type is "groove", and it can also be expressed as "adding and subtracting grooves"; "Φ 12.5
"String plastic washer" is a special label, especially indicating the head diameter of this screw. The value is φ 12.5, and the series of gaskets are plastic gaskets.
Why is the specification difference of screws so big? Moreover, domestic specifications are different from international ones. In addition to the different applications in different places, the most important point is that we all use millimeters as the unit, while the United States uses inches as the unit. Everyone knows that millimeters and inches must be different, right? Just like the exchange rate of coins, the exchange rate and its value are of course different from place to place. Well, that's the brief introduction I gave you. I hope I can help you.