Want a set of standard pitch table, who knows?

The pitch of metric standard teeth is as follows: m1.6 * 0.35m2 * 0.4m2.5 * 0.45m3 * 0.5m4 * 0.4m5 * 0.8m6 *1.0m8 *1.25m10 *. 2.0m16 * 2.0m18 * 2.5m20 * 2.5m22 * 2.5m24 * 3.0m27 * 3.0m30 * 3.5m33 * 3.5m36 * 4.0 Turning Threads The method of machining the workpiece surface into threads is called turning threads. Threads are divided into triangular threads, trapezoidal threads and square threads according to tooth types (Figure 1). Among them, the commonly used metric triangular thread is the most widely used. Figure 1 thread type 1. Basic tooth profile of common triangular thread The basic tooth profile of common triangular thread is shown in Figure 2; The names of basic dimensions are as follows: Figure 2 Basic tooth profile of common triangular thread D- internal thread large diameter (nominal diameter); D- major diameter of external thread (nominal diameter); D2—— internal thread middle diameter; D2—— pitch diameter of external thread; D 1- internal thread diameter; D 1- external thread diameter; p-pitch； The height of the original triangle. There are three basic factors that determine the thread: the included angle between two sides of the internal thread in the axial section of the thread. Metric thread α = 60o; Inch thread α=55o. Pitch p is the distance between corresponding points in the axial direction between two adjacent teeth. Thread diameter D2(d2) It is the diameter of an imaginary cylinder, and its theoretical height is H of a flat thread. The thread thickness is equal to the groove width at the middle diameter. Only when the diameters of internal and external threads are consistent; The two can cooperate well. 2. Methods and steps of turning external thread (1) Preparation for installing threaded turning tool (1); The tool tip angle of the turning tool is equal to the thread profile angle α = 60o; Its rake angle γo=0o can ensure the tooth profile angle of the workpiece thread; Otherwise, the tooth profile angle will produce errors. Only when rough machining or thread precision is not high; The rake angle can be γ o = 5o ~ 20o. When installing the threaded turning tool, the tip of the tool is aimed at the center of the workpiece; And use the template to align the knife; Ensure that the bisector of the tool tip angle is perpendicular to the axis of the workpiece; The tooth profile angle of the car will not be skewed. As shown in figure 3. Fig. 3 Geometric angle of thread turning tool and tool alignment with template 2) Turning thread excircle according to thread specification; And cut the line length termination line according to the required length. Firstly, lathe the outer diameter of the thread to size; Then a micro-visible line is carved on the thread end of the workpiece with the tip of the knife; As a tool withdrawal mark for turning threads. 3) according to the spacing p of the workpiece; Check the signs on the machine tool; Then adjust the position of the handle on the feed box, change the number of teeth of the gear of the change gear box, and get the required workpiece pitch. 4) Determine the spindle speed. Novices should adjust the spindle speed of the lathe to the lowest. (2) Methods and steps of threading 1) Determine the starting position of threading depth; Adjust the scale of the middle slide to zero; Drive; Make the tool tip slightly contact with the surface of the workpiece; Then quickly adjust the scale of the middle skateboard to zero; In order to calculate feed. 2) Try to cut the first spiral and check the pitch. Shake the bed saddle to 8~ 10 teeth from the end face of the workpiece; The transverse feed is about 0.05. Drive; Close the opening and closing nut; Turning a spiral line on the surface of the workpiece; Exit the turning tool at the thread termination line; Open the reverse handle and return the turning tool to the right end of the workpiece; Stop the car; Check whether the pitch is correct with a steel rule. As shown in fig. 4a. 3) Adjust the back eating amount with a dial; Start cutting; As shown in fig. 4d. The relationship between the total reverse feed ap and the pitch of the thread is based on the empirical formula AP≈0.65 p；; The amount of back-eating knife is about 0. 1. 4) When the turning tool approaches the finish line; Should be prepared to stop the knife; First, quickly exit the turning tool; Then reverse the car and exit the tool rest. As shown in fig. 4e. 5) transverse feeding again; Continue cutting until the correct tooth profile is turned as shown in Figure 4f. Fig. 4 Thread cutting method and step 3. Notes on threading 1) Pay attention to and eliminate the "idle stroke" of the carriage 2) Avoid "disorderly threading". When the first spiral is completed; Turn after the second feed; The tip of the knife is not in the original spiral (spiral pile); But left or right; Even the car is in the middle of the top of the tooth; This phenomenon is called "random threading", and the way to prevent random threading is to use reverse (positive and negative) turning method. When turning threads by cutting angle method, the moving distance of the small carriage should not be too large; If the tool is damaged during turning, it is necessary to change the tool again or lift the opening and closing nut unintentionally; Pay attention to the knife in time. 3) Tool alignment: Before tool alignment, install the threaded turning tool; Then press the start-stop nut; Go straight (note that it should be empty) and stop; Move the small and medium-sized carriage so that the tip of the knife accurately falls into the original spiral groove (be careful not to move the large carriage); At the same time, according to the position in the spiral groove, re-mark the feed of the middle carriage; Then take back the turning tool; Open backward; Retract the car to the threaded head; Then feed the knife. Be sure to pay attention to the car on the right when aiming at the knife. 4) Borrowing tools: after the depth of thread turning is fixed; Move the carriage forward or backward a little before turning; Pay attention to the moving distance of the carriage when borrowing knives; So as not to cause the "disorderly buckle" of the width of the tank car; 5) When threading with two thimbles; When the workpiece is unloaded and then rotated again; You have to set the knife first; 6) Safety precautions: (1) Check whether all handles are in the threading position before threading; Prevent blind driving. (2) the clues should be concentrated; Quick action; Sensitive response; (3) When turning threads with high-speed steel turning tools; Head speed should not be too fast; So as to avoid tool abrasion; (4) Prevent the lathe tool, tool rest and carriage from colliding with chuck and bed end; (5) When tightening the nut; The turning tool should be withdrawn from the workpiece; Prevent turning tool from cutting hands; Do not drive to tighten or pull out nuts; (6) The rotating thread cannot be touched by hand or wiped with cotton yarn. 4. Quality analysis of turning external threads The causes and prevention methods of waste products when turning threads Table Calculation of thread diameter First of all, you should understand the detection of threads; The bottom diameter is not the main dimension; Thread is used to measure the pitch diameter; Of course, the base diameter is a free tolerance. Generally cutting external threads; The base diameter is equal to the product of the nominal diameter minus the pitch and 1.3; This 1.3 is a constant; I ask for memories. Secondly, it depends on the obtuse angle or arc radius of the tip of the thread cutter you grind; This means that the depth of cut 2.4 mentioned in the book is actually an example; For reference; Is not an exact value; Measure the pitch diameter with a thread micrometer during thread cutting; Or clamp the steel needle at both ends of the thread; Measure with an outside micrometer; But the tolerance needs to be calculated according to the diameter of the steel needle and the angle of the thread; Generally, the thread micrometer is used to measure the above example: base diameter =30-2* 1.3=27.4, while the thread outer diameter needs to be reduced by pitch * 10%=0.2, and the cutting depth = outer diameter-base diameter =(30-0.2)-27.4=2.4. & gt comment on thread types; According to the different purposes of threads, they can be divided into: 1. International metric thread system: threads adopted by China's national standard CNS. The top of the tooth is flat; Easy to turn; The bottom of the tooth is round; To increase the thread strength. The thread angle is 60 degrees; Specifications are expressed in meters, and external threads can be divided into coarse teeth and fine teeth. Expressed as M8x 1.25. (m: code, 8: nominal diameter, 1.25: pitch). 2. American standard thread: the top and root of the thread are flat; The strength is even better. The thread angle is also 60 degrees; Specifications are expressed in teeth per inch. This thread can be divided into coarse teeth (NC); Fine teeth (nf); Very fine tooth (nef) class iii. Expressed as 1/2- 10NC. (1/2: external diameter; 10: number of teeth per inch; NC code). 3. Unified thread: formulated by the United States, Britain and Canada; Is a common English thread at present. The thread angle is also 60 degrees; Specifications are expressed in teeth per inch. This thread can be divided into coarse teeth (UNC); Fine teeth (UNF); Very fine teeth (UNEF). Expressed as 1/2- 10UNC. (1/2: external diameter; 10: number of teeth per inch; UNC code) 4. Pointed v thread: the top and root are pointed; Weak strength; Not good either. Not often used. The thread angle is 60 degrees. 5. whitworth thread: the thread adopted by British national standard. The thread angle is 55 degrees; The symbol is "w" Suitable for rolling manufacturing. The expression is as follows: W 1/2- 10. (1/2: external diameter; 10: number of teeth per inch; W code). 6. Joint thread: standard thread specified by DIN in Germany. Suitable for the connection of light bulb and rubber tube. The symbol is "Rd". 7. Pipe thread: thread used to prevent leakage; Commonly used for gas or liquid pipeline connection. The thread angle is 55 degrees; It can be divided into straight pipe thread code "P.S., N.P.S" and inclined pipe thread code "N.P.T."; Its taper is1:16; That is, 3/4 inch per foot. 8. Square thread: high transmission efficiency; Second only to ball thread; But it can't be adjusted by nut after wear; Because of its shortcomings. Generally used for vice screws and crane threads. 9. Trapezoidal thread: also known as trapezoidal thread. The transmission efficiency is slightly less than that of square thread; But it can be adjusted with a nut after wearing it. The metric thread angle is 30 degrees, and the English thread angle is 29 degrees. Generally used as the lead screw of lathe. The symbol is "Tr". 10. sawtooth thread: also known as oblique thread; Only suitable for one-way transmission. Such as screw jack, pressurizer, etc. The symbol is "no" 1 1. Ball thread: the thread with the best transmission efficiency; Difficult to manufacture; Extremely high cost; It is used in precision machinery. Such as the lead screw of a numerical control machine tool. British bolt LH 2n5/8× 3-13 UNC-2A (1) LH is left thread (RH is right thread; Can be omitted). (2)2N double threads. (3)5/8 inch thread; The outside diameter is 5/8 inch. (4) The length of three bolts is 3 inches. (5) 13 thread has 13 teeth per inch. (6)UNC unified standard thread coarse teeth. (7) Secondary coordination; External thread (3: tight fit; 2. China cooperation; 1: loose fit) a: external thread (can be omitted) b: English thread with internal thread: the size of English thread; Usually expressed by the number of threads per inch of thread length; Called "teeth per inch"; Exactly equal to the reciprocal of the pitch. For example, a thread with 8 teeth per inch; Its spacing is 1/8 inches. Thread processing method (Figure) The method of processing internal and external threads on the workpiece; There are mainly two kinds of cutting and rolling. The application of the thread principle can be traced back to the spiral water lifting tool created by the Greek scholar Archimedes in 220 BC. 4th century AD; Mediterranean countries began to apply the principle of bolt and nut to the press of wine making. At that time, the external threads were all wrapped around a cylindrical rod with a rope; Then carve according to this mark. The internal thread is usually formed by hammering with soft material wrapped around the external thread. About 1500 years; Italy Leonardo? In the sketch of thread processing device drawn by Leonardo da Vinci; There is an idea of machining threads with different pitches with the mother screw and the exchange gear. Thereafter; The method of mechanical thread cutting has been developed in European watch manufacturing industry. 1760; British brothers J. Wyatt and W. Wyatt obtained a patent for cutting wooden screws with a special device. 1778; Englishman J ramsden once made a thread cutting device driven by a worm gear pair; It can process long threads with high precision. 1797; Maudslayh, England. On his improved lathe; Turning metal threads with different pitches by using mother screw and exchange gear; The basic method of turning thread is established. 65438+1920s; Maudslay manufactured the first batch of taps and dies for thread processing. At the beginning of the 20th century; The development of automobile industry has further promoted the standardization of thread and the development of various precise and efficient thread processing methods. Various automatic die opening heads and automatic shrinkage taps have been invented one after another; Start applying thread milling. In the early 1930s; Thread grinding appeared. Although the wire rolling technology was patented as early as19th century; However, due to the difficulty in mold manufacturing; Development is very slow; Until world war ii (1942 ~1945); Due to the need of ammunition production and the development of thread grinding technology, the precision problem of mold manufacturing has been solved. Achieve rapid development. 1) thread cutting generally refers to the method of machining threads on the workpiece with forming tools or abrasives; There are mainly turning, milling, tapping, tapping, grinding, grinding and cyclone cutting. When turning, milling and grinding threads; Every rotation of the workpiece; The transmission chain of the machine tool ensures that the turning tool, milling cutter or grinding wheel moves a lead accurately and evenly along the axial direction of the workpiece. When tapping or tapping; The cutter (tap or die) makes relative rotation with the workpiece; And the tool (or workpiece) is guided to move axially by the preformed thread groove. Forming turning tool or thread combing tool can be used to turn threads on lathe (see thread processing tool). Turning threads with a forming turning tool; Because of the simple structure of the tool, it is a common method to produce threaded workpieces in small batches. Turning the wire with a wire comb cutter; High production efficiency; However, the cutter structure is complex; It is only suitable for turning fine teeth and short threads in medium and large batch production. Generally, the pitch accuracy of trapezoidal thread turning by ordinary lathe can only reach 8~9 grades (JB 2886-81; +0; The same below); Machining threads on a special thread lathe; Productivity or accuracy can be significantly improved. 2) Thread milling: milling with disc milling cutter or comb milling cutter on the thread milling machine. Disc milling cutter is mainly used for milling trapezoidal external thread on screw, worm and other workpieces. Comb milling cutter is used for milling internal and external common threads and tapered threads; The length of the working part of the multi-edge milling cutter is greater than the length of the thread to be processed; Therefore, the workpiece can be machined only by rotating 1.25~ 1.5. High productivity. The pitch accuracy of thread milling can generally reach 8~9 grades; The surface roughness is R5~0.63 micron. This method is suitable for mass production of threads with average precision or rough machining before grinding. 3) Thread grinding is mainly used to process the precision thread of hardened workpiece on the thread grinder. Thread grinding can be divided into single-line grinding wheel and multi-line grinding wheel according to the different cross-sectional shapes of grinding wheels. The pitch accuracy that can be achieved by single-wire grinding wheel grinding is 5~6 grades; The surface roughness is R 1.25~0.08 micron; Grinding wheel dressing is more convenient. This method is suitable for grinding precision screws, thread gauges, worms, small batches of threaded workpieces and shovel grinding precision hobs. Multi-line grinding wheel grinding is divided into longitudinal grinding method and cut-in grinding method. The width of grinding wheel in longitudinal grinding method is less than the length of grinding thread; When the grinding wheel moves longitudinally for one or several strokes, the thread can be reversely ground to the final size. The width of grinding wheel in plunge grinding method is greater than the length of grinding thread; The grinding wheel cuts into the surface of the workpiece radially; The workpiece can be ground for about 65438 0.25 revolutions; Higher productivity; But the accuracy is slightly lower; Grinding wheel dressing is more complicated. The cut-in grinding method is suitable for large-scale shovel grinding of taps and grinding of some fastening threads. 4) Thread grinding is a nut or thread grinding tool made of soft materials such as cast iron; Carry out forward and backward rotary grinding on that position where the thread to be proces has pitch error on the workpiece; So as to improve the pitch accuracy. Hardened internal threads are usually eliminated by grinding; Improve accuracy. 5) Tapping and tapping are to screw the tap into the pre-drilled bottom hole on the workpiece with a certain torque to process the internal thread. Turning thread is to cut the external thread on the rod (or tube) workpiece with a mold. The machining accuracy of tapping or tapping depends on the accuracy of tap or die. Although there are many methods to process internal and external threads; However, the internal thread with small diameter can only be processed by tap. Tapping and tapping can be operated manually; Lathe, drilling machine, tapping machine and tapping machine can also be used. 6) thread rolling: the workpiece is plastically deformed by a forming and rolling die to obtain threads. Wire rolling is generally carried out on a wire rolling machine. Thread rolling machine or automatic lathe with automatic thread rolling head; Suitable for mass production of external threads of standard fasteners and other threaded connectors. Generally, the outer diameter of the rolled thread does not exceed 25mm; The length shall not exceed 100 mm; Thread accuracy can reach Grade 2 (GB197-63); The diameter of all blanks is approximately equal to the middle diameter of the thread to be machined. Internal threads generally cannot be rolled; However, for soft workpieces, the internal thread can be cold extruded by slotless extrusion tap (the maximum diameter can reach about 30 mm); The working principle is similar to tapping. The torque required for cold extrusion of internal thread is about 1 times of the torque required for tapping; Machining accuracy and surface quality are slightly higher than tapping. The advantages of wire rolling are: the surface roughness is less than that of turning, milling and grinding; Due to cold working hardening, the strength and hardness of the rolled thread surface can be improved; High material utilization rate; Productivity is twice as fast as cutting; Easy to realize automation; The rolling die has long service life. However, rolling thread requires that the hardness of workpiece material should not exceed HRC40；; It requires high dimensional accuracy of the blank; The precision and hardness of the rolling die are also high; It is difficult to make molds; Not suitable for thread with asymmetric hobbing. According to the different rolling dies; Thread rolling can be divided into thread rolling and thread rolling. Two thread thread thread rolling plate are arranged oppositely, and that staggered interval is1/2; Fixed static plate; The moving plate does reciprocating linear motion parallel to the stationary plate. When the workpiece is fed between two plates; The moving plate moves forward to press the workpiece by friction; Its surface is plastically deformed to form threads. There are three kinds of thread rolling: radial thread rolling, tangential thread rolling and head thread rolling. Radial thread rolling: two (or three) thread tooth thread rolling wheels are installed on parallel shafts; The workpiece is placed on the bracket between the two wheels; The two wheels turn in the same direction at the same speed. One of the wheels also moves radially. The workpiece rotate under that drive of the thread roll wheel; The surface is radially pressed to form a thread. Lead screw with low precision requirement; A similar method can also be used for roll forming. Tangential thread rolling: also known as planetary thread rolling; The rolling tool consists of 1 rotating center line roller and 3 fixed arc line plates. When rolling silk; The workpiece can be continuously fed; Therefore, the productivity is higher than that of wire rolling and radial wire rolling.