What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The main categories of screws include ordinary screws, machine screws, self-tapping screws and expansion screws. Cap screws used to be limited to full-thread fasteners. Hex cap screw and Hex bolt Hex bolt As the name suggests, it is a male threaded fastener with a hexagonal head, designed to be turned with a wrench. According to the ASME B18.2.1 standard, the head height and shank length tolerance of the hexagon head screw (Hex cap screw) is smaller than that of the general hex bolt (Hex bolt), so the ASME B18.2.1 hexagon screw is suitable for installation in all hexagon bolts that can be used. places, also including places where the large hex bolts are too large to be used. Socket cap screw (also known as socket head screw or) is a screw with a hexagonal inner hole on the head, which can be tightened or loosened only after a hexagonal ruler (hex key, Allen wrench or Allen key) is inserted into the inner hole. The most commonly used hexagon socket head screws are cylindrical head screws with a head diameter of about 1.5 times the main diameter of the thread (1960 series). Countersunk head cap screw. The counterbore design allows the screw head to rotate without being exposed on the surface of the fixed object, so it is mostly used in places where the surface is small and traditional wrenches are inconvenient to use. Machine screw is generally a screw (4#~12#) with a diameter less than ¼ inches, usually full teeth and rotated by a screwdriver, such as slotted, cross or hexagon socket. Wood screws, machine screws; but can be divided into many categories according to different uses; machine screws can be divided into longitudinal tightening screws and horizontal expansion screws; according to the thread can also be divided into: A: Triangular thread (60 degrees ) : combined/locked/expanded B: triangular thread for pipe (55 degrees): combined/locked 3) C: trapezoidal thread (30 or 29 degrees): power transmission D: square thread (90 degrees): power transmission stainless steel screw Stainless Steel Anti-Drop ScrewsStainless Steel Anti-Drop Screws Machine (Treadmill) Screws And Shafts For Motorcycle Or Bicycle Needle Car Screws, Axes Screws And Shafts For Sewing Macing Socket Set Screws Stainless Steel Wide Thread ScrewsStainless Steel Coarse Thread Screws Stainless Steel High-Low Thread Screws Stainless Steel Machine Screws Stainless Steel Self Drilling Screws Stainless Steel Self Tapping Screws Stainless Steel Self Tapping Screws Stainless Steel Thread Cutting Screws Stainless Steel Triangle Stainless Steel Tri-Lobular Thread Screws Model Description P refers to the head type is PAN head; A refers to the pointed tail teeth, B refers to the flat tail teeth, namely PA round head pointed steel teeth, PB round head flat mouth steel teeth. Self-tapping type: ◆Round head self-tapping screw PA ◆Round head flat tail self-tapping screw PB ◆Round head cutting tail self-tapping screw PT ◆Round head belt self-tapping screw PWA ◆Round head belt and flat tail self-tapping PWB ◆Round head belt Jiecut tail self-tapping PWT ◆Countersunk head self-tapping screw KA ◆Countersunk head flat tail self-tapping screw KB ◆Countersunk head cut-tail self-tapping screw KT ◆Semi-countersunk head self-tapping screw OA ◆Big head self-tapping screw BA ◆Big head flat tail self-tapping screw BB ◆Large flat head self-tapping screw TA ◆Large flat head flat tail self-tapping screw TB ◆Large flat head cutting tail self-tapping screw TT ◆Thin head self-tapping screw CA ◆Thin head flat tail self-tapping screw CB ◆Cup head hexagon socket self-tapping HA ◆Drywall/Wallboard/Fiber Nails Machine Wires: ◆Round Head Machine Screw PM ◆Round Head Machine Screw PWM ◆Large Flat Head Machine Screw TM ◆Countersunk Head Machine Screw KM ◆Half Countersunk Head machine screw OM ◆Large head machine screw BM ◆Thin head machine screw CM ◆Cup head machine screw HM
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 13 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
Many existing products need to use screws in the production process, especially in the field of nuclear power sluice gates, it is necessary to fill a part of the sluice gate with screws to fix the size and structure. If the fixing effect is not good, then It will lead to more leakage of water gates, waste a lot of water resources, and even cause safety accidents.
Standardized mechanical parts for fastening connections. Standard fasteners mainly include bolts, studs, screws, set screws, nuts, washers and rivets. There are many structural types of bolts, and most of the heads are hexagonal. For bolts subjected to shock, vibration or variable load, in order to increase flexibility, the polished rod part is made into thin sections or hollows. The seat end of the stud is screwed into the threaded hole of the connected piece, and the nut used at the nut end is similar to the bolt nut. The structure of the screw is basically the same as that of the bolt, but the shape of the head is various to adapt to different assembly spaces, tightening degrees and connection appearances. Set screws have different head and tip shapes to accommodate different levels of tightening. Nuts are also available in a variety of styles, with hexagons being the most widely used.
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