How to distinguish between coarse thread and fine thread, what is the difference between fine thread

The difference between the coarse tooth thread and the fine tooth thread is the difference in the pitch size, the coarse tooth is a large pitch, and the fine tooth pitch is smaller, according to the thread self-locking schematic diagram, it can be seen that the spiral rise angle of the fine tooth is smaller, which is more conducive to the self-locking of the thread, so the fine tooth is generally used in the place where it needs to be prevented from loosening. The thread pitch of the fine thread is smaller, and compared with the coarse thread, the number of teeth screwed into the fine thread thread is more at the same thread length, which can play a role in reducing fluid leakage, so it is used in the occasion of sealing. Fine threads can also play a role in fine-tuning due to the advantages of small pitch.

The coarse thread is the general standard thread, that is, the coarse thread is generally used, which can facilitate the interchangeability of the equipment connection.

In general, coarse teeth are used. The coarse thread has a small number of teeth of the same length, so there is no cross-sectional size of one tooth.

Larger, better stressed, more suitable for bearing greater tension and impact.

In short, the two kinds of threads have their own characteristics, the key depends on what occasion it is used, there is no fixed who is good and who is bad, the key depends on the place used.

Not according to the big trail, but according to the trail.

The thickness of the thread you are talking about is relative to the ordinary triangle thread, and there is such a provision in the triangle thread standard: how much pitch is used for the thread under normal circumstances. If you want to use a pitch smaller than the standard pitch, it is called a fine thread. Because the pitch is different, so the trail is also different.

No, the fine thread and the coarse thread are relative to the nominal diameter, such as m25*2. Do you think he's coarse-toothed or fine-toothed?

Although there is a national standard thread too.

But it doesn't apply in many places.

The pitch is not the same.

The pitch of the fine tooth is small, which is suitable for precision parts or thin-walled parts.

The pitch must be marked after the fine tooth thread, and the coarse tooth is not marked.

The G thread is the pipe thread, and the M thread is the normal thread. The various screws and nuts we commonly use are M threads, and the various pipe connections we use at home are G threads, such as tap water taps, water heater halts, and interfaces are G threads.

Hello, 1, the unit is different.

G represents the imperial pipe thread, the tooth angle is 55 degrees, and the large, medium and small diameter dimensions and the number of teeth per inch are marked in imperial units, and M represents the metric ordinary triangular thread, and the tooth angle is 60 degrees. The dimensions of each part are in millimeters.

2. The sealing is different.

G refers to the pipe thread of non-threaded sealing: the tooth angle is 55 degrees, the internal and external threads are cylindrical pipe threads, which do not have tightness after fitting, and only play a connecting role in the pipeline, and can be used for low-pressure pipelines under static load with the help of sealing rings. The top and bottom of the tooth are rounded.

M refers to the pipe thread sealed with threads: the profile angle is 55 degrees, and it has tightness after screwing. The top and bottom of the tooth are rounded. The taper of the taper thread is 1:16. There are two kinds of fits:

The G thread is a 55 degree non-threaded seal pipe thread and belongs to the Wyeth thread family. The national standard can be found in GB T7307-2001

Generally, 1 8 3 8 1 2 or 2 points 3 points are used.

M threads are generally 60 degree triangular buckles. Metric threads, standard in mm outer diameter.

Although it is confirmed that the demand curve arises naturally from the theory of consumer choice, the derivation of the demand curve itself is not a theory that proposes consumer behavior. Simply determining how people react to change doesn't require a rigorous analytical framework. However, consumer choice theory is extremely useful.

As we will illustrate in the next section, we can use this theory to more deeply determine the factors that determine family behavior.

Instant Answer Draw budget constraint lines and indifference curves for Pepsi and pizza. Illustrate what happens to the budget constraint line and consumer optimum when pizza** rises. Use your graph to divide this change into income effects and substitution effects.

Four applications. Now that we've established the basic theory of consumer choice, we can now use it to illustrate four questions about how the economy works. However, since each problem involves family decision-making, we can address these issues with the consumer behavior model we just proposed.

Are all demand curves sloping to the bottom right?

In general, when an item** goes up, people buy less. Chapter 4 refers to this normal behavior as the law of demand. This pattern manifests itself in the demand curve sloping to the lower right.

However, as far as economic theory is concerned, the demand curve also sometimes slopes to the upper right. In other words, consumers sometimes defy the law of demand and buy more when one item rises. To illustrate how this can happen, look at Figure 21-12.

In this example, the consumer buys two items – meat and potatoes. Initially, the consumer budget constraint line was a straight line from A to B. The best advantage is c.

When the potato ** rises, the budget constraint line moves inward and is now a straight line from A to D. Now the best thing is e. It is important to note that the rise in potatoes has led consumers to buy more potatoes.

The thread diameter is the nominal diameter of the product. The large diameter of the thread refers to the nominal diameter of the product, and the small diameter of the thread is the diameter of the valley bottom, that is to say, it refers to the diameter of the bottom of the external thread, and the middle diameter of the thread refers to the imaginary cylinder, and the cylindrical bus bar is at the same place as the width of the tooth groove and the protrusion, and the middle diameter is the diameter of the cylinder, which is usually the average of the large diameter and the small diameter.

Definition of the large diameter of the threadFor example, the large diameter of the M2 external thread is 2, the small diameter is, the middle diameter is, what does the large diameter of the thread mean and the middle diameter of the thread means, the large diameter of the thread means the nominal diameter of the product, and the small diameter of the thread is the diameter of the valley bottom, that is to say, it refers to the diameter of the bottom of the external thread. The middle diameter of the thread refers to the illusion of a cylinder, and its cylindrical busbar is at the same width as the tooth groove and the protrusion, and the middle diameter is the diameter of the cylinder, which is usually the average of the large diameter and the small diameter.

g stands for non-sealed cylindrical pipe thread, 55 degree tooth profile.

3 4 refers to 3 4 inches, and the number of teeth in each is 14, pitch.

for, the thread tooth is high.

The basic diameter of the thread: the large diameter and the small diameter.

Inch threads. The size of the thread is marked in the imperial system, and it is divided into two types: cylindrical and conical according to the shape; According to the angle of the tooth type, it is divided into two types. The 8 mark in a thread refers to the diameter of the thread size in inches.

One inch is equal to 8 points, 1 4 inches is 2 points, and so on.

In thread calling, coarse and fine teeth are distinguished by pitch.

Coarse thread: no need to mark the pitch, such as M8, M12-6H, M16-7H, etc., mainly used as a coupling thread, compared with the fine thread, due to the large pitch, the thread angle is large, if the tooth deformation becomes larger, the self-locking becomes worse: the tooth pitch becomes larger, the tooth profile also becomes deeper, and the strength of the main component is also reduced.

Fine thread: The pitch must be marked to show the difference from the coarse thread. These characteristics are the opposite of coarse teeth. It is specified to supplement the special requirements for coarse threads. Fine teeth are also available in pitch series.

Difference 1: The labeling is different.

Coarse thread: There is no need to mark the pitch, such as M8, M12 6H, M16 7H, etc.

Fine thread: The pitch must be marked to show the difference between the thread and the coarse thread.

Coarse thread: mainly used for coupling threads, compared with fine threads, due to the large pitch, the thread lifting angle is also large, the self-locking performance is poor, generally used with spring washers, the pitch is large, the tooth profile is also deep, and the strength of the body is also reduced. The advantage is that it is easy to disassemble and assemble, and the standard parts supporting it are complete and easy to interchange.

Fine thread: the characteristics are just the opposite of the coarse thread, in order to supplement the coarse thread can not meet the special use requirements and stipulated, the fine thread also has a pitch series, mainly used in the hydraulic system of metric pipe fittings, mechanical transmission parts, thin-walled parts with insufficient strength, space-limited internal parts and shafts with high self-locking requirements.

For example, the external thread:

1. The largest diameter is the large diameter.

2. The bottom of the screw is the path.

3. The middle diameter is used to check the size of the through, and it is also the standard for testing the thread angle, which is in the middle part of the thread fastener.

4. Each different thread has the same standard size as the slag infiltration, and you can consult the thread standard.

The differences between the use of coarse threads and fine threads are as follows:

1. The characteristics are different.

Coarse teeth do not need to mark the pitch, mainly used for coupling threads, compared with fine threads, because of the large pitch, the thread rise angle is also large, the self-locking performance is poor, generally used with spring washers: the pitch is large, the tooth profile is also deep, and the strength of the body is also reduced. The advantage is that it is easy to disassemble and assemble, and the standard parts supporting it are complete and easy to interchange.

Fine tooth must be marked with pitch, in order to show the difference with the coarse thread, the characteristics and coarse thread is just the opposite, in order to supplement the coarse thread can not meet the special use requirements and stipulated, fine thread also has pitch series, mainly used in the hydraulic system of metric pipe fittings, mechanical transmission parts, thin-walled parts with insufficient strength, space-limited machine internals and self-locking requirements on the shaft.

2. The strength is different.

The strength of the coarse thread is high, and the sealing of the fine thread is good. The same level ensures that the load difference is not much (slightly higher for the fine teeth), and the preload of the two is close when fastening. When anti-loosening measures are not taken, the anti-loosening effect of fine tooth threads is better than that of coarse teeth, and is generally used for thin-walled parts and parts with high requirements for vibration resistance.

3. Different application occasions.

Coarse threads are generally used for the mass production of threaded fasteners, such as bolts, screws, nuts, etc. It has unique advantages in the barbaric operation occasions that require rapid assembly or disassembly and some barbaric operations that are prone to rust and damage. However, its self-locking performance is not as good as fine tooth and ultra-fine tooth thread.

Fine threads are often used where high strength of fasteners is required. Because the fine thread is shallower than the coarse thread and the thread diameter is larger, the thread strength is higher than that of the coarse thread of the same nominal specification. In addition, fine threads can be used for fine adjustments.

The differences between metric threads and pipe threads are as follows:

1. The application is different.

Pipe thread is a thread machined on the cone of the pipe, which is used to connect various pipes, and is conducive to the sealing of the pipe due to the taper. It is an inch thread. Ordinary threads are used to tighten bolts and nuts for various equipment, and are divided into metric and imperial systems.

Pipe threads are mainly used for the connection of pipelines, and the internal and external threads are tightly matched, and there are two kinds of straight pipes and conical pipes. The nominal diameter refers to the diameter of the connected pipe, and obviously the large diameter of the thread is larger than the nominal diameter.

2. The unit representation is different.

Metric threads are expressed by pitch, and American and British threads are expressed by the number of threads per inch, which is their biggest difference, the metric thread is 60 degrees equilateral, the imperial thread is isosceles 55 degrees, and the American thread is 60 degrees. Metric threads are in metric units, and American and British threads are in imperial units.

3. The numbers are different.

There are two types of buckles, one is imperial and the other is metric. Compare the thread with the buckle rail, and that fit belongs to that kind of thread. Graduation number of metric threads:

Wait a minute; Graduation number for inch threads, etc. He means something different.

The number of the metric thread indicates the distance of the thread. The number of the imperial thread represents the number of teeth per inch.