What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The performance grade 8.8 of stainless steel bolts refers to the material's tensile strength limit of 800MPa and yield limit of 640MPa. The performance grades of stainless steel bolts, studs and studs are divided into 10 grades: from 3.6 to 12.9. The number before the decimal point represents 1/100 of the tensile strength limit of the material, and the number after the decimal point represents 10 times the ratio of the material's yield limit to the tensile strength limit. There are 7 grades of performance grades for nuts, from 4 to 12. The numbers roughly represent 1/100 of the minimum stress that the stainless steel nut is guaranteed to withstand. For unified inch threads, there are three thread grades for external threads: grades 1A, 2A and 3A, and three grades for internal threads: grades 1B, 2B and 3B, all of which are clearance fits. The higher the rating number, the tighter the fit. Classes 1, 1A and 1B, very loose tolerance classes, which are suitable for tolerance fits of internal and external threads. Grades 2, 2A and 2B are the most common thread tolerance grades specified for inch series mechanical stainless steel fasteners. Grades 3, 3A and 3B, screwed together to form the tightest fit, suitable for tight tolerance stainless steel standard parts, for safety critical designs. Metric threads, there are three thread grades for external threads: 4h, 6h and 6g, and three thread grades for internal threads: 5H, 6H, 7H. Thread fit is best combined into H/g, H/h or G/h. For bolts, stainless steel nuts and other refined fastener threads, the standard recommends 6H/6g fit. Carbon steel: The strength grade is marked by ? It consists of two separated numbers. The meaning of the number part before the ? in the marking code represents the nominal tensile strength, for example, 4 in grade 4.8 represents 1/100 of the nominal tensile strength of 400N/MM2. The meaning of the ? and the number part after the point in the marking code represents the yield-strength ratio, that is, the ratio of the nominal yield point or the nominal yield strength to the nominal tensile strength. For example, the yield point of grade 4.8 products is 320N/mm2. The strength grade mark of stainless steel products consists of two parts separated by —. The symbol before — in the sign code indicates the material. Such as: A2, A4 and other signs — indicate strength, such as: A2-70 Carbon steel: The mechanical properties of bolts can be divided into: 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9, 12.9 in total 10 performance levels
slotted screw comprises a screw rod, one end of the screw rod is connected to the middle of the bottom surface of the screw head, the side wall of one end of the screw rod away from the screw head is provided with a screw slot in the vertical direction, the screw The bottom surface of the head is in seamless contact with the top surface of the buffer wear-resistant pad, the buffer wear-resistant pad is connected with the screw rod by threads, and the buffer wear-resistant pad is provided with several shock-absorbing holes equally spaced along the circumference.
Figure 1 is a schematic structural diagram of Guangdong Yueluo Hardware Industry Co., Ltd. Figure 2 is a front view of the structure of the riveted positioning block. FIG. 3 is a top view of the structure of the riveted positioning block. Figure 4 is a front view of the structure of the riveting lower die. Figure 5 is a side view of the structure of the riveting lower die. 1, I is a rivet, 2 is a riveting positioning block, 3 is a product, 4 is another product, and 5 is a riveting lower die. [0017] Referring to Figure 2, Figure 3, 2-1 is a positioning pin, 2-2 is a rivet hole, and 2-3 is a through hole. Referring to Figure 4, Figure 5, 5-1 is a positioning hole, 5-2 is a guide block, 5_3 is a countersunk screw hole, and 5_4 is a vacant hole.
The side wall of the bolt hole is threaded, and the top of the nut is provided with several flattening notches. According to the locking nut of the preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the number of flattening notches is three. Due to the above features, the three flattening notches can be used as the focal point of the tightening tool, and the
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
