Question 2: What is the difference between self-tapping screws and ordinary screws? What does "self-attack" mean? Self-tapping screws are screws that do not need to be matched with existing tapping parts.
Machine screw is a kind of screw that must be matched with threaded parts. I don't know what you mean by "ordinary screws".
In fact, both self-tapping screws and machine-threaded screws are common, but the pitch is common.
Question 3: What do self-tapping screws 4×35 4 and 35 mean respectively? Yu Wenlong, a fastener consultant, believes that 4 indicates that the thread size of the self-tapping screw is 4mm, and 35 indicates that the screw length is 35 mm
Yu Wenlong, a fastener consultant, thinks it's best to look up relevant information yourself. Everything I got online was fake. If you don't know how to pretend, you can answer casually. It is simply false or deceptive, which will directly mislead you and even hurt you. The light products are unqualified, and the heavy ones will be fined. Of course, Yu Wenlong, a fastener consultant, thinks that if you have the strength, it is also a good choice to ask relevant consultants to refer to your technology, grasp the development direction of the enterprise, locate products and customers.
Question 4: What is a self-tapping screw? What does "self-attack" mean? Tapered screw. Screw the tapered thread directly into the object to fix the two objects together. Generally used in wood, plastic, sheet metal, etc.
Question 5: What is a self-tapping screw? What does "self-attack" mean? There are three definitions here: 1. "Self-tapping screw" needs to be drilled in advance, and the drilled hole is slightly smaller than the diameter of the screw. For example, drill a 4 mm screw with a 3.2 drill bit. Then, when the self-tapping screw is screwed in, it can "tap" the thread. 2. The "self-drilling screw" can be directly drilled (installed on the electric drill) without drilling in advance. However, "self-drilling screws" can only be driven into thin iron sheets below 0.5 mm. There is also a kind of "drilling tail screw", which can directly drive in 3-4mm angle steel without drilling in advance. In fact, there is a drill bit at the front end of its screw, so it is more appropriate to call it "drilling screw". Self-tapping screw means: the hole drilled is a hole without tapping, and the screw used is different from the general one. The head is sharp and the pitch is large, which is a bit like tapping without tapping, so you can screw it in directly. This method is usually used for metals and plastics. Self-tapping screws: generally refers to end wood screws, with thick teeth and hard texture, and are also used in aluminum alloys and plastics. A special self-tapping screw used to tap metal holes is called tapping. Screws refer to all, including screws and screws; Self-tapping screws are used for nonmetal or soft metal, and there is no need to drill low holes and tap; Self-tapping screws are pointed to enable self-tapping. Ordinary screws are flat-headed, with the same thickness.
Question 6: The difference between self-tapping screws is 10 points 1. Self-tapping screws are generally fingertip tips, coarse teeth and hard surfaces, and are used for nonmetallic or soft metals such as wood and plastic, such as aluminum alloy and sheet metal parts, without drilling low holes and tapping.
2. Self-tapping screws are generally pointed and have a certain taper, so that they can be self-tapping; Ordinary screws are flat-headed and have the same thickness.
3. It can use its own thread to "drill, squeeze, press and tap" the corresponding thread on the fixed material to make it fit closely.
4. Types of self-tapping screws:
(1) (thread-rolling self-tapping screw)-triangular self-tapping screw, also known as type (Thai type is still patented), is developed according to the principle of forming tapping. The thread-rolling self-tapping screw has a specially designed thread and tail end, which enables the screw to roll itself into the matching internal thread under intermittent pressure.
(2) (Self-drilling and self-tapping screws)-Also called Tec, in all the processes of assembling self-tapping screws, the most expensive thing is the preparation of pre-drilling. You must drill holes before using self-tapping screws. And the aperture must be limited. Without pre-drilling, the cost can be saved in some aspects. This is a self-tapping screw that can be drilled, tapped and tightened in one operation.
High C and low self-tapping screws-used for plastics or other low-density materials. Double thread design, high thread (with larger tooth outer diameter) has flatter and sharper thread type, and the thread angle is 30 degrees. The thread angle of low thread (with small external diameter of teeth) is 60 degrees, and the height of teeth is only half of that of high thread. The combination design of high and low threads reduces the rotating torque, improves the pull-out strength, and greatly reduces the risk of fracture of the combined workpiece. It is also used for drywall assembly in the construction industry and has the following advantages.
(3) (Double-lead self-drilling point self-tapping screw)-When assembling, you can easily screw in the gypsum board, drill holes in the steel bar, and tap the matching internal thread. The horn head has a concave bearing surface, which will not damage the wallpaper or plaster surface when screwing in. Most self-tapping screws are used for commercial purposes. For example, when self-tapping screws are provided as assembly screws (SEMS), they can provide a closer service.
5. Identification characters of standard self-tapping screws, including symbols for thread and tail shape:
(1) Self-tapping screws have one or two characters representing threads to represent mechanical threads or spacer threads.
"B" stands for wide thread screw.
No "b" refers to mechanical thread.
(2) The tail character is used to distinguish whether the self-tapping screw is thread forming, cutting, rolling or self-tapping drilling.
The thread angle of wide thread is 60 degrees, but the pitch is wide, and the thread lead is larger than that of mechanical thread because of the wide pitch and steep thread.
Another thread specially used for plastics, with a thread angle of 48 degrees, is commonly known as PT tooth screw.
(3) Thread-forming tapping screws A, AB, B, BP and C have been gradually replaced by thread-rolling tapping screws, which are not recommended in the new design. AB, B, BP just have different shapes of tails. AB has a tapered tail with thread, B has a blunt tail, and BP has a tapered tail without thread. The center of the pointed tail enters the pre-drilled hole and begins to shape the thread.
(4) Tapping screws for thread cutting are in the form of BF, BP, D, F, G and T, BF and BP are wide threads, and the rest are mechanical threads. The difference of a recognized character lies in its truncation. Each cutting tail is shaped to collect the cut waste. If the self-tapping screw is screwed into a blind hole (not a through hole), its fragments will remain and be sealed at the bottom of the hole. However, if it is tapped into the through hole, the waste will fall on the other side of the workpiece. Therefore, this must be considered when choosing this type of self-tapping screw. Waste may cause pollution, fall into moving parts or make electronic substrates inoperable.
6. All thread-rolling self-tapping screws are mechanical threads, which are the same as the coarse threads of Anglo-American unified threads. Please refer to SAE J8 1. For metric threads, please refer to SAE J 1237 and DIN 750 ...>>.
Question 7: What do self-tapping screws mean? Where self-tapping screws are used, it is not necessary to drill holes and tap teeth on the workpiece before driving. Self-tapping screws have self-tapping function.
Question 8: What are self-tapping screws and metric screws? Generally, it is a wooden screw with thick teeth at the fingertips, and aluminum alloy and plastic are also used. A special self-tapping screw used to tap metal holes is called tapping. Self-tapping screws are used for nonmetal or soft metal, and there is no need to drill low holes and tap; Self-tapping screws are pointed for self-tapping; Ordinary screws are flat-headed and have the same thickness. Self-tapping screw means that the drilled hole is a chip-free self-tapping hole, and the screws used are different from ordinary ones. The head is sharp and the pitch is large, which is a bit like chipless tapping. You can screw it in directly without tapping. This method is usually used for metals and plastics. Self-tapping screws are screws without nuts. It can use its own thread to "drill and squeeze" the corresponding thread on the consolidated material to make it fit closely.
Question 9: What is the difference between self-tapping screws and ordinary screws? Threads are divided into external threads and internal threads. Generally speaking, the thread on the bolt is external thread, while the thread on the nut is internal thread.
Self-tapping screws do not need internal threaded nuts, and internal threads are drilled on the material when screwing in.
Self-tapping screws are generally used for materials with low hardness, such as aluminum alloy, and the thickness of the material is not very thick.
If it is steel, even stainless steel, you can't use self-tapping screws.
Question 10:3/4 What does self-tapping screw mean? This is an inch thread, that is, a self-tapping screw with 3/4 inch thread. If you want to buy it, just quote directly. But you still need to know the length In addition, domestic English screws are not easy to buy, so it is best to find a monopoly place.