How to calculate the length of the thread and how to calculate the basic size of the thread?

The length of the female thread should be consistent with the length of the screw.

The length of the screw refers to the length of the part of the two threads that fit each other along the axis of the thread, the value of the screwing length should be moderate, increasing the screwing length within a certain range can effectively improve the bonding strength, but the length of the spinning is too long not only will not improve the bonding strength, but will also reduce the quality of the joint, and increase the cost. According to the size of the nominal diameter and pitch of the thread, the national standard stipulates three sets of screwing lengths for the thread connection: short screwing length (S), medium screwing length (N) and long screwing length (L).

The value of the medium length of the rotation is a multiple of the nominal diameter. Specific to your design, you only need to select the screw length group and mark it in the part drawing, e.g. M6 medium screw length group is not marked, refer to the thread marking method).

Length of screw** can be found in GB T197-2003 or in the mechanical design manual.

Of course, the longer the thread screw length, the better the threaded connection strength. For example, a threaded screw length of 3 mm, and a 50 mm, 50 mm screw connection is definitely better.

Generally speaking, the larger the pitch, the stronger the threaded connection. Because the threads are shaped, such as the commonly used triangles, the larger the pitch, the larger the thread, and of course the more stable the connection.

The hole can be measured with a vernier caliper.

The effective length of the hole is not necessarily. You can check the thread length of the bolt of the M3.

Pipe thread standard: The basic size that measures the size of the pipe thread.

M3 is 3 threads with a spacing of 3 10 mm.

Thread diameter basic size (d1 or d1) = thread basic size (d or d) - pitch (p) coefficient (coefficient =

The working height, the distance between the overlapping parts of the two-phase fitting thread profile perpendicular to the thread axis, etc. The nominal diameter of the thread is the nominal diameter except for the pipe thread, which is the nominal diameter of the inner diameter of the pipe. Threads have been standardized and are available in metric (metric) and imperial systems.

The international standard uses the metric system, and China also uses the metric system.

Pipe threads are used for tight connections of pipe fittings. The rectangular thread has high efficiency, but it is often replaced by trapezoidal thread because it is not easy to grind and it is difficult to screw and center the inner and outer threads. The working edge of the serrated threaded tooth is close to the rectangular straight edge and is mostly used to withstand unidirectional axial forces.

Metric thread basic size calculation formula:

Pitch t Outer Spiral Diameter D - Nominal Diameter of External Thread.

Median diameter d2= t

Inner diameter d1= t

The theoretical height h= t

Working height h= t

Corner radius r=h 6= t

The thread size is calculated as follows:

Calculation of the basic size of the ordinary thread: the most basic size of the thread determined by the design is the nominal diameter and pitch l about the nominal diameter, the national standard has been serialized, and the largest pitch of each nominal diameter is called the coarse tooth ordinary thread (except for the third series), and the rest are fine tooth ordinary threads. The national standard stipulates that the profile angle of ordinary threads is 60°

Theoretically, the calculation is; Thread minus (pitch multiplied by. Assume M16* thread. The threaded bore is 16-(this is the metric thread algorithm.)

To put it simply, it is. We know that the metric thread is an equilateral triangle, in fact, the thread inner hole is to find the height of this equilateral triangle. The formula for calculating the height of an equilateral triangle is the metric thread calculation method for dividing the side length by 2 times the root number 3 or more.

The imperial thread is an isosceles triangle with a apex angle of 55 degrees. To convert the bottom edge. In the search for high. Then calculate according to the above formula. Assuming that the metric circle is converted from imperial to metric, the inner hole of the 16 * thread (the length of the bottom edge of the thread) is 16-(.

Model M22: StandardPitch

The pitch categories are as follows:

1. Thread pitch. It refers to the axial distance between two points corresponding to two adjacent teeth on the thread on the middle diameter line.

2. The pitch in the model airplane. Propeller.

The distance traveled by the plane of the paddle by making one rotation in the air.

3. Pitch of particles in a magnetic field. If the velocity v of a charged particle is angular to b when it enters a uniform magnetic field b, the particle will move in a spiral.

The pitch is calculated as follows:1. Metric thread.

For example, where is the pitch, there is no need to calculate;

2. Imperial and American threads.

The algorithm is to divide by the number of teeth within an inch to get the pitch.

For ordinary threads, the tooth angle is 60 degrees, then there is a formula for tooth height = pitch, and the pitch cannot be calculated by the formula, but the fixed value specified in the national standard.

Summary. Dear, hello, I have found out for you that the length of the thread is counted from the head of the thread to the length of the tail of the thread, that is, the effective length of the thread. 1. The thread length is calculated according to its bearing capacity, and there is an upper limit.

The lower limit is set according to the actual processing situation. 2. Your case should be between 20-30mm in length, the thread is a figure composed of wire types, and there are many kinds of it. The most intuitive is the spiral protrusion with a specific cross-section made on the surface of a cylinder or conical matrix.

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Dear, hello Paiyuan, I have found out for you that the length of the thread is from the head of the thread to the length of the tail of the thread, that is, the effective length of the thread. 1. The thread length is calculated according to its bearing capacity, and there is an upper limit. The lower limit is set according to the actual processing situation.

Dust Ming State 2, your case should be between 20-30mm in length The thread is a graphic composed of line types, and there are many types of it. The most intuitive is the convex part of the Huaiyan spiral with a specific cross-section made on the surface of the cylinder or conical matrix.

Calculation of the large diameter of the thread:

The upper limit calculation formula d-ges is the basic size of the thread with a large diameter - the benchmark deviation;

The formula for calculating the lower limit is d-ges td, i.e., the basic size of the thread with a large diameter - reference deviation - tolerance.

Calculation of trails:

The basic size of the thread diameter = the basic size of the internal thread - the pitch factor.

Precautions for calculating the large diameter of the thread:

1. The large diameter of the thread is determined by the diameter of the thread smooth rod blank and the tooth wear degree of the thread rolling wheel of the thread rolling plate, and its value is inversely proportional to the middle diameter of the thread on the basis of the same blank and thread processing tools, that is, the small middle diameter is large and the diameter is large, and the large diameter is small on the contrary.

2. For the parts that need to be processed by heat treatment and surface treatment, considering the relationship between the processing process, the large diameter of the thread should be controlled at the lower limit of 6H level during the actual production, such as the large diameter of the external thread of M8 in the rolling (rolling) wire should be guaranteed to be above and below.

Notes on the calculation of the diameter of the thread:

1. The tooth height of the internal thread is directly related to the size of the bearing moment of the internal thread, so it should be within the upper limit of 6h level as far as possible in the production of blanks.

2. In the process of internal thread processing, the smaller the diameter of the internal thread, the more effective the use of the tool-tap. From the point of view of use, the smaller the trail, the better, but when considering comprehensively, the trail is generally between the middle limit and the upper limit, and if it is cast iron or aluminum, the lower and middle limit of the trail should be used.

3. The diameter of the 6G grade of the internal thread can be implemented according to the 6H level in the production of the blank, and its accuracy grade mainly considers the plating of the middle diameter of the thread, so only the middle diameter size of the tap is considered in the thread processing and the diameter of the light aperture is not considered.

17835mm。

Inner diameter = outer diameter 10825x pitch. The calculation formula of the inner diameter is: inner diameter = outer diameter 10825x pitch, for example, the inner diameter of the thread of M20*2 = 200825*2 = 17835mm.

Thread profile:

Normal, trapezoidal, rectangular and zigzag threads. Thread thread types mainly include ordinary threads, namely triangular threads, trapezoidal threads, rectangular threads, and creepy zigzag threads.

Meaning of thread large diameter and small path:

The large diameter of the thread refers to the nominal diameter of the product. The thread diameter is the diameter of the base, which means that it refers to the diameter of the base of the external thread.

The thread has large diameter d, d, medium diameter d2, d2, small diameter d1, d1, and the nominal diameter is used when representing the thread, and the nominal diameter is the diameter representing the thread size. The nominal diameter of an ordinary thread is the large diameter.

For example, the large, medium and small diameters of the external thread are represented by d, d1 and d2. The internal threads are represented by d, d1, and d2. The large diameter refers to the imaginary cylinder diameter of the base brigade stool tangent to the crest of the external thread or the base of the internal thread. The underpath is the base of the external thread. <>