Hello everyone, today I'm going to introduce the thread type knowledge. Regarding the thread part, we actually use it very often in life or in the industry. There are actually many types of threads, unless we are people in a specific field . Some people may have some misunderstandings or problems of confusion, such as the most common confusion between metric and imperial, or the confusion between imperial and American, and sometimes we will see what threads are PT and PF. You may know It is not clear, and some machine tools use trapezoidal threads or some special ones . I will introduce how to distinguish threads in a while. In fact , there are quite a few types of threads. Today, we will divide them into five categories. Explanation Because if you learn too much , some threads that are not used often will cause greater misunderstandings, so today they are divided into five categories. As long as we know these five categories, basically the threads we encounter in life or in the industry are basically the same. It can be processed and distinguished here . How do we know it? Let’s keep reading. The first thing to introduce is the metric thread. The most commonly used metric thread is the screw and the nut . There is a detail here. Enlarge the place. It is some related thread parameter calculation formulas. We will not use them in general formulas. Unless you want to draw a real thread , it may be used. There are some special tools for general processing, such as thread tapping or Marukoma . It is possible to directly use the car to turn the thread out. Here is the metric thread representation. There will be an M in front of it . The most important thing is to know that its angle is 60 degrees. It is expressed by the thread pitch. So if you want to know this The screw specification or thread specification see the lower left corner. The general metric coarse tooth representation is like this. If it is M3x0.5, you can know that the nominal diameter is 3 and the pitch is 0.5. Like here M6x1.0 pitch 1.0 The nominal diameter is 6 M12x1.75 The pitch is 1.75 and the nominal diameter is 12. This side belongs to the coarse tooth part . For example, sometimes fine teeth may be used, such as M8x1.0 M10x1.25, etc. Generally, if there is no mark, it is mainly expressed in metric coarse tooth. Here, let's get to know you first. Generally , the most common is the metric thread, which is expressed as nominal diameter x pitch. Let's get to know it here . Next, we will introduce the inch thread, the inch thread, which has another name , Webster or Wyeth thread . There will be a W in the notation. It is often seen that the British thread is confused with the American thread. When I talk about the American thread, I will mention it a little. The British thread is very common in Taiwan. Usually , it is expressed in Taiwanese for 2 points. , 3 points, 4 points, like this way . How to distinguish the representation of the number of teeth. There is another chapter for more details. The understanding of the inch teeth. If you are interested, you can go to the description at the bottom of the video. What you need to know is that in the inch thread, it is W , so the thread angle on this side is 55 degrees, this side needs to be special Note that the metric system is 60 degrees just now , which is different in the imperial system. It is 55 degrees. Its representation will also be different. In addition to W, the size of the inch system is followed by the size of its teeth. What is the number of teeth in an inch? As seen here, 1/4-20 has 20 teeth per inch, and 3/8-16 has 16 teeth per inch. Basically , the imperial system is generally Generally speaking , if you want to buy screws, the ones that are often seen in Taiwan should be 2.5 or 3 points. Like this, let me introduce you to everyone. If you are in the engineering field, you will basically know There is an extra W here, so that you will know the inch thread or the Wyeth/Webster thread. Here , let's get to know you first . The next thing to introduce is the American thread, which has another unified standard thread. This place is basically It is most likely to be confused with the imperial system because its representation is very similar. The difference is that there is a UNC/UNF or No at the back. The main difference is actually the thread angle. The imperial system is 55 degrees in In the American system, it is 60 degrees. Note that it is 60 degrees here. Others are basically the same. Its representation is very similar. For example , 3/8-16 in the American system is UNC and UNF. Where is the difference? UNC is coarse tooth UNF, it is fine tooth So seeing 3/8-16 UNC so it's US coarse 3/8-24 UNF it's US fine Here we would like to say 3/8-16 is in imperial and it 's also 3/8-16 here It is easy to be confused, so look at it . If there is a W in front of it, it means it is inch. The inch here is 55 degrees, so when you buy screws or screw taps, if you buy 3/8-16 UNC , there is basically no way to lock the inch screws. Attached here to pay special attention , here in Taiwan, pay attention to in "Taiwan" Taiwan will use American thread is very, very, very rarely, so if you are expressing it, it is for Taiwan processing plants , which basically use the British system, here is special Note that the imperial system is 55 degrees, so you must be very careful when it is expressed like this. Some processing factories will find this American-made screw tap and make it for you according to your needs, and then you will find that the screw cannot be locked in . Be careful not to confuse the British system with the American system. Other special ones like this 4-point tooth 1/2 are -13 in the American coarse tooth. The number of teeth per inch is 13 in the British system. 4 points (1 / 2-12) The number of inch teeth is 12. This place is quite different. Others are basically the same. Also let everyone know that it has No. For example, No.12-24 UNC UNC is coarse teeth - 28 UNF is fine teeth, the same is true In No.12, 24 teeth and 28 teeth represent 28 teeth per inch, and the number of teeth is relatively thin. In addition, it has other representations, such as 12#, which means American standard screws or It's a nut. Another way of saying it is called the number of teeth. If you see this type of number of teeth or 12#, 10#, 8# screws and nuts, you must be very careful. Generally , it is relatively rare in Taiwan, so pay attention to it. Yes No, it actually needs the imperial system, but there may be some confusion after the query, so you should pay special attention when selecting or designing. Basically, the biggest difference is the angle. The American system is 60 degrees, and the British system is 55 degrees. Here is to pay attention to the American system and the British system. Where is the difference? Taiwan does use less American teeth . Pay attention to this, and you will not choose the wrong one. Next , I will introduce the pipe thread. The pipe thread may not be clear to some people. This meaning is used in pipes. Threads are roughly divided into two categories: straight pipes and tapered pipes, and then tapered pipes are more common . Pipe threads are often seen like water pipes or some air pressure oil pressure joints . PT teeth are often seen, and PT teeth are often heard. It refers to pipe threads. The tapered tube inside can be roughly understood first. Note that it is also 55 degrees here. It is more common . Of course, there are also American ones. The American system is 60 degrees . The thread is used as a demonstration of a 55-degree straight pipe. It can be seen from the picture. This is straight. The tapered pipe means that it has an inclination angle . The inclination angle is 16:1. Here is the taper of the standard taper PT tooth. As long as you know that it has a taper and then 55 degrees, it can be PF or G in the straight tube representation. It is the same as the number of teeth per inch as indicated on the screen. It is very similar to the inch system. It is often seen here . It is a tapered pipe thread. Generally , it can be compared with other PT teeth or Rc and R. PT teeth are the most common . 3 points of PT teeth The size of PT teeth here is not the same as that of the imperial system, and the calculation formula is not the same. If you want more details here, you can go to the pipe thread knowledge article, where there is a more detailed talk. Today is the main point of identification. Threaded PT teeth are very common and generally seen in hardware stores, such as T-shaped water pipe joints or three-way crosses , or pneumatic tools such as air guns or pneumatic screwdrivers, etc., PT teeth will be seen, so PT teeth will generally be attached to The combination of "Busilu" and "Puxilu" is the anti-leakage tape (leakage tape) when it is used to lock the PT teeth, it will be wrapped around the "Puxilu" to lock it in. In this way , the anti-leakage effect will be improved. Better, its main taper is leak-proof, leak -proof, air-leakage, water-leakage or oil-leakage. PT teeth are all used, so the places where PT teeth are used are very extensive. As long as you understand, you will know. Here, let everyone know what the pipe thread is and how to use it. Go to those parts. Next , we will introduce the trapezoidal thread. The trapezoidal thread may be very unfamiliar to some people. If you are in the field of mechanics, you may have heard of the Aikem thread in school or during the exam . In fact, the Aikem thread is a trapezoid. Thread It is very common to hear that Aikem thread is used here, such as machine tools, machine tools such as lathes and milling machines, and you may see trapezoidal threads . It is a transmission component, so there are roughly two types of trapezoidal threads. Tr It is very easy to distinguish between Tw metric system and imperial system. When you see the metric trapezoidal thread Tr, it is 30 degrees here, and the imperial system is 29 degrees. This kind of resolution is enough. You don’t need to know too much about other details . The most important thing to know is whether it is 30 degrees or 30 degrees. 29 degrees and then again, the metric Tr size is the most common, the inch part has to be touched, and it is enough to understand it in depth. For example, the representation of Tr10x2 here is very similar to the metric thread, that is, the nominal diameter is followed by the pitch , which is it. P Tr10x2 is the nominal diameter of 10 , and its pitch is 2. Tr22x5 means the nominal diameter is 22. The pitch is 5. See that it is very similar to the metric thread. Because the inch part is relatively rare, I will not introduce it more deeply to avoid confusion. Let everyone know it here. Aikem thread is a trapezoidal thread, and the most common one is metric 30 degrees. Finally, let’s summarize the thread types. In fact, today we mainly introduce five types of threads, which are the more common types of threads. In fact, there are many types that have not been introduced, as you may hear You may have heard of needle thread, round thread, square thread, or even bicycle thread, but these are relatively special and may only be used in some specific industries. Basically , the general industry is less used here. What may be unclear is the metric system or the British system and the American system, especially the British system and the American system, which are too similar to be confusing, and the PT teeth may not be clear to some people. Here are the five main categories to know . How to distinguish the type of thread and how to look at the specification to choose the correct thread . Generally, when making threads, you may need a screw tap. To choose a screw tap , you must find the correct specification. For example, the inch and the US system choose the wrong specification. You may not be able to find such screws . For example, American-made threads are rare in Taiwan. It may be imported from abroad. It will be more troublesome here. When you want to know the thread, you are often confused. There are many kinds of information on the Internet, but you are still not clear . You can use this method to understand how to quickly distinguish these five categories. Today's teaching is mainly here, and we are looking forward to it. Let's teach next time Bye~ Bye~
