How to cut threads with a cutter correctly. Paines for carpentry vice. Trapezoidal thread
Trapeziidal running thread for metal.cutting taps and Lerok
Carpet for cutting the trapezoidal thread is shown in the rice. 200. The angle between the side cutting of the cutter should be 30 °; The length t of the front edge is taken according to the profile of the chopped thread. All angles (α, α1, α2) are selected in the same way as the angles for cutting a rectangular thread. And in this case, the holdings are used to fix the incisors (see. rice. 199). The cutter for cutting the trapezoidal thread is pulled according to the template, like the sharpening of incisors for triangular threads, and in the same order. The sharpened cutter is brought.
Рис. 200. Резец для нарезания трапецеидальной резьбы
Trapezoidal cutting techniques. The cutter is installed when cutting the trapezoidal thread is carried out in the same way as with a rectangular thread. Threads with a step up to 3 mm are cut with one cutter with a full profile. Cutting threads, the step of which exceeds 3 mm, is carried out in several techniques (rice. 201, a). Gigg the width of which is 0.1-0.2 mm less than the width of the threads of the thread, a screw groove is cut through. The diameter of the groove “along the bottom” should be equal to the inner diameter of the chopped thread. After that, two incisors (right and left) spiral groove are given the shape of the trapezoid, and the width of the groove measured in the outer diameter should be 0.3-0.4 mm less than the final. Each of the incisors should have an angle at the top equal to 30 °; The length of the front cutting edge of the incisor is made 1-3 mm less than the width of the hollow of the chopped thread. The final threading is carried out by a cutter with a full profile. Only the side sides of the thread profile are finished with this cutter.
Рис. 201. Приемы нарезания трапецеидальной резьбы
Another, very productive method of cutting the trapezoidal thread is shown in the rice. 201, b. A cutter whose width is 0.3-0.4 mm less than the final width of the screw groove measured along the middle diameter of the thread, the preliminary groove is cut through. The diameter of the groove measured “along the bottom” should be larger than the average thread diameter of 0.3-0.5 mm.
Then the preliminary groove deeps up to the inner diameter of the thread.
The width of the cutter used should be 0.2 mm less than the final width of the hollow. Profile finishing is carried out sequentially by two incisors with a full profile of chopped thread. The first of the incisors has a concave (in the form of a groove) front surface, which provides a greater ease of chips and a clean thread surface. The second cutter should have a flat front surface.
Checking the trapezoidal thread. To check the trapezoidal thread, maximum calibers are used, similar in design with maximum calibers for triangular thread. The profile of the trapezoidal thread is checked by a protrusion from the template if it is necessary to determine the average diameter of the trapezoidal thread, its check is carried out indirectly. To do this, the template is superimposed on the turn of the thread, as shown in the rice. 202. If the bottom of the notification of the template applies to the top of the profile of the thread, and points A and B. its sides, the average diameter of the thread is correct.
Рис. 202. Шаблон для проверки профиля и среднего диаметра трапецеидальной резьбы
It should be noted that this method of checking the average diameter is rough, since the external diameter of the thread, the accuracy of which depends on the result of the verification of rice. 202, processed with a low degree of accuracy. The exception of this is the screws with the trapezoidal thread (running screws), in which the side surface serves as a installation base, when cutting threads using lunets. The outer diameter of such screws is therefore more precise than that of ordinary.
Features that the trapezoid in the thread provides
Original angles-profiles of 15-40 0 and lifting of 30 0 causing drawing of grooves;
Minimum friction (with the correct selection of lubrication);
Self.instruction, practically eliminating the likelihood of deformation of the part, even if serious loads affect it;
Impressive wear resistance (better than pipe or rectangular).
The most clearly these properties are manifested in notches with an average step: with their use, quite accurate axial movements are achieved.
Checking the distance between the turns is easiest with a caliper: measure the plot on the rod, consider the number of grooves, divide the length found for this number, get the result, check it with reference data and make sure that it is within normal limits.
Now about why in the accompanying documentation you can often see the record “Trapeziidal TR thread”: GOST 9484-81, which also regulates the marking, establishes that the Latinage should be used when applying conventions. And these two letters just talk about the form of notches.
Such a profile pattern has a number of advantages:
When placing in the middle of the double radius, it is not difficult to identify radial gaps.
Complex devices and functionally complex objects can be dismantled and designed with it, and the process of their design is simplified.
Due to the screw and nuts, it ensures the transformation of rotation into progressive movement, which means it positively affects the overall performance of the mechanisms.
Allows you to regulate the compression force as necessary, which speeds up the assembly of functional components.
Does not reduce the strength or other useful characteristics of the finished product. the material is affected by the material, not the quantity or geometry of the turns.
But the carving of the trapezoid, the dimensions of which we will consider below, also have certain disadvantages:
If friction is still observed, it provokes the appearance of significant stresses in the areas of the depressions.
Such a cutting pattern is not suitable for the mechanisms used for strong vibrations. with constant fluctuations, fasteners can arbitrarily removed.
High cost in multi.building performance. are relatively high, demanding on the technological base, in their production a lot of electricity and time are spent.
Therefore, it is relevant not everywhere, but in strictly defined areas. it is applied to specific details, the number of which is usually extremely limited.
How to cut the thread manually
Threaded connections are widely used in the device of various mechanisms and machines. Bolts, studs, screws, nuts. these are universal, interchangeable fasteners. However, there are times when you need to cut the thread manually. A specialized tool will help to perform this work efficiently.
In mechanical engineering, three main systems of fasteners are distinguished: metric, inch and pipe.
Metric threads are most widely used. It has a triangular profile with an angle of 60 °. Its main parameters, diameter and step, are expressed in millimeters. Example of designation: M16. This means that the thread is metric, has a diameter of 16 mm with a large step 2.0 mm. If the step is small, then its value is indicated, for example, M161.5.
The diameters of inch and pipe threads are expressed in inches. The step is characterized by the number of threads per inch. These parameters are standardized, so there is always the opportunity to choose the necessary tool.
External thread cut
The following tools and materials will be required to cut out the outer thread: a dick or a trumpet, a dress holder, a file, a vice, a caliper, machine oil.
The most widespread are round dies (Lerki). They are whole or sequent. Diameters of whole round dies are standardized. This allows you to choose the right option from a large row of size, for example, M10, M12, M14, M16.
A feature of the split dies is the ability to adjust the diameter of the chopped thread within 0.1 0.25 mm. However, they have reduced rigidity, which affects the accuracy of the resulting profile.
The dick is installed in the dress holder of a suitable size. After that, it is fixed using screws. In the case of external pipe thread, a dress holder with a rattle is often used. They provide convenience of working in hard.to.reach places, for example, near the wall.
The thickness of the rod is chosen by 0.1 0.25 mm less than the diameter of the external thread. For example, for M6 with a large step, this is 5.80 5.90 mm; M8. 7.80 7.90 mm; M10. 9.75 9.85 mm. Measurements are performed using a caliper.
To ensure the best cutting of the dick, at the end of the rod, the chamfer is washed down. Its width should be 1. 1.5 mm for M6 M18. The workpiece is lubricated with machine oil, which facilitates subsequent work and allows you to get a better surface.
The dick is applied to the end of the rod so that its plane is perpendicular to the axis of the chopped bolt. Then, with a slight pressure, the plane holder is rotated clockwise (if the thread is left, then counterclockwise).
Когда плашка врежется в стержень на одну-две нитки, её следует повернуть на пол-оборота назад для лучшего удаления стружки. After that, 1-2 revolutions are made again along the thread and 0.5-in the opposite direction.
Acting according to this scheme, the bolt is cut into the required length. The diameter of the outer thread is checked with a regular nut or caliber-ring. If necessary, the step is controlled by the threaded meter.
Inner thread cutting with a tap
The following tools and materials are necessary for the formation of internal threads:
First of all, the workpieces are marking and the center of the future opening is melted. Select a drill corresponding to the required thread diameter. This can be done using reference tables or approximately according to the formula d = d. p. Here D is the diameter of the thread, p is its step, d is the diameter of the drill. For example, for M10 d = 10. 1.5 = 8.5 mm.
A hole is drunk into the part to the required depth, which should exceed the length of the cut part. With the help of a drill with a diameter more than D, on the edge the holes perform a chamfer. It serves for centering and the best tap tap.
Taps for cutting threads: types, tables of sizes, GOST requirements
You can make a thread in a finished metal hole or nut in just seconds if you have a tap. Using this metal.cutting tool, you can apply an internal thread and calibrate the existing.
Of course, taps are not the only tool used to create a thread. For example, dicks and dicks fall into a similar category. They are used to apply a part of the part. But now it’s not about that.
There are quite a few types of taps. experienced masters did not even hear about some of them. Therefore, we will leave the specific types of this tool to narrow specialists and analyze the most popular. Let’s try to choose a tool for specific needs. On the algorithm presented below, this will not be difficult.
Fields of application: home workshop or production
Obviously, when working at home and at work, the master will need a different tool.
Manual taps (they are also locksmith) will be found in any workshop. Due to significant strength and wear resistance, the tool allows you to perform the operation of high accuracy even in domestic conditions. They are usually equipped with a special gorge needed to rotate the tap.
Manual taps are almost always sold by sets of 2-3 pieces of different diameters. Each tool carries out its own task: one carvings are launched by one, the second (if there is). intermediate, the third. finishing, after which the profile meets all GOST standards (about them below).
But manual taps are not designed to work at high rotation speeds. Machine analogues are used for this.
Machine taps are made of better high-speed steel, which easily tolerates serious heating that occurs due to friction and cutting metal. It is precisely in strength that locksmith taps are inferior to their machine counterparts. In addition, machine tools have a small fence part, t.to. The alignment of the tap and the hole of the workpiece is provided by the design of the machine.
There is another third type of taps. wiper. It is easy to guess that they are used exclusively to apply threads in nuts. Washing taps have a long shank, which is installed in a special automatic machine.
After applying the thread, the nuts move to the tail one after another and expect there when the whole series is completed.
After that, the tap is removed from the cartridge, and all the nuts are dumped into the receiving tray. Thus, the time for operation is significantly saved, and the performance increases.
Type of hole: deaf or through
The purpose of your work is of no small importance: are you going to create a profile in a dense hole or a through hole? Depending on this and the tool will need various. In particular, grooves for the tap tap will play a big role. They can be twisted (both left and right), but can be located directly.
Right.line grooves are used in universal taps.
Tools with right deepening of the grooves are more often used to create a profile in deaf holes. On such grooves, the chips are squeezed back, out, and does not clog the hole.
Rifle grooves directed to the left are used to create a profile in through holes. The chips are squeezed right in front of the tap, thereby preserving the incapacitated thread from damage.
There is another version of taps with chopped grooves of shortened length, known as non.binding, or rolleries. This design helps to create a thread in products made of viscous materials, for example, from alloyed high.strength and low.carbon viscous steels, as well as aluminum alloys.
There are several state standards in production that differ in the measurement system. With the help of marking on a tap, you can understand which of them the tool belongs to. metric or inch. Based on the type of tap device, you can apply three types of threads.
Metric taps are useful to create a profile, the dimensions of which are measured in millimeters. They are marked with the symbol “M”. The profile of taps of this type is an isosceles triangle with an angle at a top of 60 °.
The dimensional row of metric taps is quite extensive. with their help you can create almost any profile. Each size of the tap has its main step. the distance between the turns of the thread. The larger the size, the greater the main step. A special table based on state standards (according to GOST 19257-73) is used to select the tool.
Unlike metric, the size of inch taps is indicated in inches. Such a system came to us from abroad. In particular, from the USA and the UK. The main step is indicated by the number of threads (or the number of turns) per 1 inch. The higher the indicator, the smaller the thread step.
Using a TAP as Thread Boring Tool
The angle at the top in an inch thread can be different. The angle of 60 ° is characteristic of taps common in North America. Maximum popularity was gained by UNC thread. Such fasteners are often found on the equipment imported in technology (lawn mowers, generators, cultivators, etc.P.).
The inch thread of the British Standard BSW has a corner at a top of 55 °. Below are the inch dimensions of taps of the most popular standards.
Among the inch taps, it is worth highlighting a group of tools used to create a profile in pipe connections. Especially often pipe thread is found in elements of water supply systems.
The dimensions of pipe taps are specially adjusted for standard types of metal pipes. They are divided into cylindrical and conical. The former are indicated by the letter “G”, after which the figure corresponding to the passage diameter is placed. Pipe conical taps are marked with symbols “R” or “RC”. The thread is applied on the surface with a cone 1:16 and reaches the stop.
In order to correctly cut the thread with a tap, you must also stock up, in addition to electrical equipment, below the listed devices.
- A drill more than the main hole, diameter. It removes the holes from the edges of the holes, smoothes this edge.
- Drill-shurupert capable of working at low speeds.
- Manual tap. Without it, it would be necessary to pinch the tap into the cartridge of the drill, and this is not always acceptable.
- The vice is locksmithing. It is better if they can be fixed on a workbench.
- Kern and hammer, machine oil and rags.
- Having prepared all this inventory, they begin the process itself.
Here is a step.by.step guide.
- Nap the hole for the future inner thread.
- Apply a little oil to the place of the mark and on the drill itself. Excess friction will be eliminated, the drill will not overheat, which is important for its long service life. If there was no machine oil, then you can apply oil development, solidol, lard or harsh fat, for example. If a more viscous alloy is drilled, for example, stainless steel, then it is recommended to use exclusively engine oil.
- The details of small dimensions are fixed in a vice. their low weight would not allow them to stay in place. Having drilled a hole, using a drill slightly larger diameter, a sharp protrusion is removed on the surface of the part, which allows you to give a more neat view to the processed area. You can use a stepped or conical drill. make sure that you do not “overshadow”: the groove of the ditches should not go deeper than a millimeter. For holes at 4 mm, you can use “drilling” at 5, for 5. by 6 mm, for 6. by 8 mm, for 8. by 10 and 12 mm and t. D.
- In the process of cutting the thread, make sure that the tap moves straight, without deviating to a degree in any of the sides. Do not forget to lubricate it and the hole itself before starting work. The cutting rule is as follows: two turns are made during the cutting of the thread, one. back. It is unacceptable to promote the tool only in the right direction, t. to. Due to increased friction and pressure, the working screw groove can dull, despite the relative hardness of instrumental steel, and the tap will immediately work worse-it will be much more difficult to form. The smallest chips formed during the cutting of the groove in the workpiece should leave the cutting part: if this is not done, then according to the laws of physics, the load on the tool will increase. Increased hardness of ordinary steel, in which a screw groove is cut, requires more oil.
- If all of the above conditions are met, the result is a free and light screwing of the hairpin or bolt into the just “chopped” hole.
Before testing the quality of work, rinse the internal walls of the hole from traces of sawdust and waste oil before lubricating it again.
Do not use a drill and other mechanical tools for cutting threads. The exception is a universal drilling machine, whose turnover is adjusted up to 0.3 per second, as well as which have reversal functions (reverse rotation). A simple drill can be damaged, like the tap itself.
It is not recommended to deviate from the vertical and perpendicularity when drilling, otherwise the drill will break. If you do the same with a tap, then you can bend it, and the centering attached to it at the factory will be violated. You can straighten the tap only using a lathe or a drill as a guideline. However, the imperfect, slightly twisting tap immediately leads to a poor.quality internal carvings in the workpiece. the bolts and studs turn hard or refuse and completely twisted to twisted.
How to cut thread on a lathe with a cutter, number of revolutions, dimension
Cutting threads on a lathe is one of the most common operations performed daily on thousands of lathes. As a working tool, cutters, threaded heads, dies and taps are used. Performing a thread using a cutter requires a special dexterity and knowledge.
The design of the lathe allows you to cut the internal and outer thread. For this, many varieties of incisors related to three large groups have been created:
Rod. the easiest type of cutting tool. This is a rod (any shape of the cross.section) with a working head. The profile is determined by the shape of the head. One of the varieties of rod incisors. with fan.fitted working faces. They are more resistant to washing and do not require frequent sharpening. Round and prismatic refers to the shaped category.
Prismatic cut only the outside. Compared to rods, they are able to work with large surfaces. The cutter is held in the holder “Swallow tail”. Capable of a larger amount of lasting than core.
Round perform external and internal threads. They cut more conveniently and have a greater range of application than prismatic. They can be dragged more times. The holder is installed relative to the end and holes.
Thread cutting technique
The cutter evenly moves along the workpiece and cuts out a fishing line for a trimmer in the shape of a screw with its vertex. The slope of the line to the axis, perpendicular to the movement of the cutter, is called the angle of increasing the screw line. This indicator depends on:
During the contamination of the cutter into the blank, it is covered with a screw groove. The thread provides reliable fastening, compaction or movement of elements in the planned direction.
Depending on the configuration of the blank, the name is given: cylindrical or conical. The profile, which is simultaneously the transpower of the projection onto the thread plane, is selected taking into account the purpose. The following profiles are most applicable:
They are cut by single.rise or multi.assembled. The second are created by several grooves located on the same gaps from each other, the first. a single groove.
The properties of the thread are determined by concepts such as step and move. the distance between the same coil elements. It equals the work of the number of suits one step.
Types and properties of incisors
The current cutting cutter consists of a holder and a working head. The quality of processing parts directly depends on these elements. The holding has a rectangular or square section. With its help, the cutter is fixed on a lathe.
The work head processes the details. It is composed of various cutting planes and edges. The angle of tightening the head is due to the material from which the part is made.
External and internal threads are cut by threaded cutters of different types.
Rod incisors consist of a rod with a working head. These types are different profiles. The most wear.resistant. incisors to which the carbide facial work faces are soldered. They do not need frequent turning, as they remain sharp for a long time.
Prismatic incisors are used to process only the outer side of the blank. Their advantage over bitch is the ability to process large surfaces. But they should be more more likely to be shifted.
Round incisors are used in the process of cutting the threads of internal and outer. These tools are very convenient to work, the field of use is wide enough. Round incisors allow reusable draining.
The threaded cutters are round
According to constructive differences, metal.cutting tools are divided into several types:
The top of any threaded tool is a rounded head or chamfer. Thread profile is formed by the cutter of the proper configuration. Cutting tools of bent shape cut a threaded thread on the surface of the blank.
Direct incisors are rarely used here. The thread inside the part is made with curved incisors, sometimes straight, fixed in a special holder.
Carriers are divided into categories:
- made from high.speed alloy steel;
- with a carbide plate attacked on a working element;
- cutting devices with interchangeable multifaceted plates fixed on the head.
In the direction of spy cutting, tools differentiate on the right and left. When working, the first is the supply from left to right, the second. the feed goes to the left. The right is used more often.
Work performance increases due to the use of threaded heads. They have 4 segments with incisors. Having cut to the end, the device is opened, releasing the part. Do not twist the tool. The thread is cut quickly, like a tap. Diameters can be processed up to 100 mm.
Threading heads have a complex design and are used in mass production of parts.
The cutting of the cutter is carried out according to the flat template, regardless of the type of thread. The angle must exactly correspond to the hollow, repeating its contours. After cutting the top of the threads should be cleaned and slightly dull. In trapezoidal profiles, the corners of the vertices and cavities are rounded to R 0.3-0.5 mm. Otherwise, the thread will be poorly twisted and rested with the peaks. With the cleaned tops when twisting the threads glide on the side surface, creating a strong connection. The maximum load and the tightness of the connection increases.
The highest performance when processing holes gives a tap for cutting internal threads. Details exhibited in the axis, he cuts out all the turns, regardless of the number of visits.
Cutting threads on turning machines
Cutting threads. an extensive theme in metalworking using turning machines. This technology is used in more than 40% of the work. The strength of the connective elements of structures or mechanisms depends on the quality of the threads. Read more about this in the article.
Methods for obtaining threads
Threaded joints are used in mechanical engineering and construction. The use of metizes with thread allows you to combine the details of the mechanisms and structural elements during construction by using bolts, nuts, screws, studs. Thread products are also designed to transmit efforts or movement in mechanisms such as a jack, gearbox, press, machine.
Jacks and running screws are made with trapezoidal thread.
There are the following methods for making threads:
- manually (tap or dick);
- On machines:
- turning and engine (mod. 16k20);
- threaded using rollers and flat dies;
- milling (mod. RTS 161F4) to obtain threads with a large step;
- grinding using circles with a given profile for the manufacture of small and accurate threads;
- screwed (mod. 1622);
- for cutting threads on nuts (mod. 2064);
- providing vortex cutting of threads using multi.cut heads.
Vorthy cutting is provided by 4 incisors located in a rotating head from its engine. This device is fixed on the caliper of the lathe. Due to the alternate cutting of the incisors, a high processing speed is provided, since the incisors heat up slightly. The smaller roughness of the resulting threaded surface and the increased accuracy of the profile are also ensured.
Thread is a screw fishing line for a trimmer formed on the surface of the body of rotation by the top of a protrusion of a certain shape. The distance between the nearby protrusions equal to the thread of the thread. The form of protrusion depends on its type. Between the two neighboring ledges is the cavity.
- Direction of the screw line:
- right (its rise occurs from left to right, and the screw screwing is carried out by the clockwise movement);
- left (screwing occurs against the movement of the clockwise).
- Forms of the protrusion in the form:
- unequal trapezoid,
- External surface of the part (cylindrical or conical).
- Locations on parts (internal or outer).
- The number of visits (one, two, three);
- Appointment (fastener and chassis).
The trapezoidal thread is inherent in greater strength than rectangular, with a lower labor intensity of manufacturing. The purpose of the trapezoidal thread is the transformation of the rotational movement into progressive.
In addition, they use a thread called modular. It is used where rotation is transmitted from the worm to the worm wheel, the axes of which are at an angle of 90⁰.
The thread is indicated: M12x1,25–7n. This means: metric internal (7n), diameter 12 mm, step. 1.25 mm, tolerance field 7n. For outdoor threads, the tolerance field is recorded: 6h. The value of a large step in the designation is not given (M16–8G). The left thread in the designation adds the letters LH (M16–8G. LH). GOST 8724–81 shows a table indicating the diameter and step of the desired size.
Dick. On the outer surface, the threads are cut into dies. They are made as a nut. To obtain cutting elements and remove the chips, holes are drilled in them. On each side, the trash has cutting elements that form a fencing cone (angle 20⁰. 30⁰). In the middle part there is a calibrating zone.
The dick is fixed in the gorge with screws. After each turning of the dick, you need to turn it back into a third of the circle. This is necessary to clean the holes from the chips and obtain a high.quality threaded surface.
Tap. The tap is used to cut the inner thread. It has cutting edges obtained in the manufacture of longitudinal or screw grooves. The grooves form the front surfaces on the teeth. The working area of the tap forms a fence and calibrating areas. The fence is also called the cutting. It is conical shape and cutting occurs gradually.
Distinguish manual, machine and ward taps. Manual taps are made single and in the kit: for draft and finishing passages when cutting threads. The kit consists of 3 taps. Its number is indicated by the number of circular scorks on the shank (1. Chernova, 2. Aporatory, 3. finishing).
The largest fence part of the draft tap. The shank in taps is made in the form of a square to transfer the working effort with a gorge. Taps are divided for cutting threads in through and deaf holes. Washing taps are made with a straight or curved shank.
Cutter. The thread is cut by the top of the cutter fixed in the caliper, when moving it relatively rotating workpiece. In this case, the threaded step formed by the cutter is equal to the distance between the peaks of neighboring protrusions along the axis of the part.
Cutters for cutting threads constructively perform:
- solid (made of high.speed steel or solid alloy);
- with attacked hard alloy plates (GOST 18885–73);
- teams with mechanical bore (interchangeable multifaceted plates).
A threaded cutter with an attacking or replaceable multifaceted plate (SMP) should have sharpening angles that ensure the receipt of the appropriate profile on the thread. Such incisors are used to cut metric and trapezoidal threads.
- SMP cutters are used on CNC turning and milling machines that can provide the necessary cutting modes and obtain the finished part for one processing cycle (processing centers).
- To ensure the quality of the thread when cutting it, coolants are necessarily used (emulsion, sulfofrezole and others).
- Stamps of high.speed steel for incisors: P6M5K5, P6M5, P9M4K8, P9K5, P12F3, P9M4K8.
Cutting threads with cutters
A widespread element of machines parts is external and internal threads in mechanical engineering, fasteners with a triangular profile, chassis with a rectangular and trapezoidal profile and conical threads are used.
The cutting of the threads is carried out by incisors (motionless and rotating), combs, dies, threaded heads, threaded cutters and taps, finishing thread processing. with grinding circles. The manufacture of threads by plastic deformation is widely used. rolling with dies and rollers.
Cutting threads with cutters
Cutting cutting by cutters is carried out on lathes.
The part installed in the cartridge or centers rotates, and the cutter, fixed to the hazeller, moves along the forming thread, and these movements are strictly agreed: for one revolution of the part, the cutter moves to the size of the thread step.
The movement of the caliper when cutting the thread is transmitted from the running screw, which is connected to the spindle through the gearbox (the gear ratio is equal to the ratio of the pitch of the cut thread to the step of the running screw).
Flat, tangential and disk single.profile or multidisciplinary (combs) cutters are used (Figure 1). Cutting profile corresponds to the profile of the threads of the thread.
Cutting Right Hand External Acme Threads on the Metal Lathe
To prevent distortion of the thread profile, it is usually dragged from the front angle equal to zero, and installed so that the front line is at the height of the centers.
The cutter is submitted in two ways: the part of the part (Figure 2 A) is perpendicular to the cutter, and the cutter works with the entire profile, and in parallel forming the thread (Figure 2b); In this case, the cutter works with one cutting edge.
When cutting threads with a large step, preliminary processing is carried out with a slotted cutter with a profile angle that differs from the angle of the thread profile by 5-10? On turning machines, threads are cut on long details or in cases where the thread should be strictly concentrative with other surfaces processed in the same installation.
Labor productivity is low, since cutting is carried out in five to ten or more passes, a lot of time is spent on the reverse progress and installation of the cutter per size. In addition, this work is performed by highly qualified workers and requires intense attention, especially when cutting the internal thread.
On accurate machines, it is possible to cut the first.class accuracy carvings.
On turning and thread.cutting machines, the threads of rotating incisors are cut. vortex or covering cutting. To do this, a device with a head driven from an electric motor is installed on the caliper of the machine.
The head is installed at an angle equal to the angle of the thread. In the head there are cuts for cutting threads (Figure 3). The part is fixed in centers or cartridge. The speed of the part is less than the speed of rotation by the cutter.
The head rotates with the number of revolutions, providing cutting speed of 100-300 m/min, and moves along with the caliper by the size of the thread step in one turn of the part. Thread cutting is carried out in one pass.
Vorthy cutting is used to process threads no higher than the second accuracy class and for pre.cutting a large thread on long parts.
The material of the article is written on the basis of the literary source “Technology for the production of internal combustion engines” m. L. Yagudin
Types of thread
Carving blanks are used in the form of cylinders and conical (conical) components. In turn, the thread is cut in the form of an external spiral (spiral) groove or as an internal. The structure of the threaded joint is determined by its profile. In practice, several specialized types are applied:
In turn, the threaded grooves are made in one or more visits. In the first case, the spiral groove is presented in the only performance: only its turns are adjacent to each other, others (related) are not used. Thread step. the distance between the central edges (recesses) of the turns adjacent to each other. The course of the threaded groove is determined by multiplying the threaded step by the number of turns or the calls of several grooves (if not one is used, but more).
Having decided on the type of threaded connection, the appropriate incisors are selected. Such a tool is a combination of a shank and working part. The quality level of screw cutting is determined by the execution of these components. The shank has mainly a square or correct multifaceted transverse section, which ensures its centering. It is difficult to fix the cutter in the clamping cartridge without a shank. The working part cuts the screw groove. It includes cutting planes and sharp edges. The angle of sharpening of the cutter is determined by the alloy from which the part is made. Basically cut steel and color metal details. Choosing the type of cutter, they begin the technological process.
Methods of cutting
Moving along the axis of rotation, the cutter leaves the screw groove on the workpiece. One of its main characteristics is the angle of rise (increasing). The angle between the imaginary axis passing through the screw groove and the plane, the perpendicular axis of the rotation of the workpiece, is calculated in accordance with the value of the cutting of the cutter and the frequency of the drive revolution (gearbox). The magnitude of the thread step is measured when moving along the axis of the chopped workpiece.
As a result, the carrier-performer will receive the cut that the client ordered. When cutting several grooves (visits), all of them are located in the form of uniform spiral recesses. An example of a multi.assembly thread cut. PET bottles and appropriate polyethylene covers, for example, for sunflower oil. The difference between lids for bottles and nuts is that in the first case the thread is short, does not contain more than one turn.
The course of the thread with a single.shot groove is equivalent to its step, and in a multi.building thread it depends on the number of agreed, but independent turns. The manufacture of incisors for one- and multi-building threads is regulated by GOST 18876-1973 standards. The same GOST prescribes a cutting of a metric, not an inch thread. According to these norms, incisors are produced in the form of prismatic, rod and round cutters.
The outer thread is cut using a bent cutting, and the internal one. through the hidden and curved cutters fixed in the working rimmer. The top of the cutter is identical to the profile of the screw groove, which it leaves for itself. Prismatic cutters are divided into single and multidisciplinary.
Disk, except for the same two varieties, is also available as a separate tool for an internal threaded groove.
This performance, in turn, takes into account the following parameters. The front angle of the cutter is determined by the parameters of the material from which the part is worked out. The angle value is from 0 to 250 degrees. When the groove is performed by means of machine equipment on parts from simple medium or low-carbon steel alloys, the angle in front is zero. The more steel is saturated with alloying additives, the larger the angle is selected, but, as a rule, it cannot be more than 100 degrees.
Increasing the shock viscosity of steel alloy forces to increase, increase hardness and fragility, on the contrary, reduce this value. If you leave the angle for fragile alloys noticeably large zero, then chips and cracks will appear on the parts. It is unacceptable to use a cutter, which at least slightly different in the profile of the cutting edges from the groove that you will need in the future.
The corners of the back and from the sides of the cutter are taken such that the cutting teeth and ledges do not wash about the insides of a spiral groove that has begun. Despite the fact that it will win or high.speed steel of special hardness as a working material, washing the cutting sharp edges will gradually lead to their diligence, and the cutter will be spoiled.
The values of these angles are set on both sides of the same value. In the case when the angle of rise, on which the working state of the thread depends, is selected less than 4 degrees, then the rear.sided angles should be set to a value from 3 to 50. With a coal, which is more than 4 degrees, the same corners will stop from 6 to 8 degrees corresponding to it.
The internal threaded groove is cut into the openings pre.drilled through the part. An alternative option for obtaining holes. pulling. Details worked from steel are finalized on a machine with carbide inserts made on the basis of steels T15K6, T14K8, T15K6 or T30K4. In the case of cutting threads on a cast.iron workpiece, other carbide cutters are used: from alloys VK4, B2K, VK6M and VK3M.
Dies and taps
Taps and dies are a wretched and screw type of tools, the inner surface with carvings in which is divided into sectors, equidistant from the central axis of the tool. The neighboring sections will be far from each other at the same distance. The current machine provides mainly by cutting metric threads. The cutters themselves also do not differ in the large value of the diameter of the workpieces for which they are designed. In the case of the use of cutters designed for machine, and not manually, the session of cutting is carried out in one reception.
The difference between machine taps and simple manual taps is the presence of a picking and calibration working zones on them. When ordinary cutters are used when cutting threads, then the master cannot do without the presence of tools for the process. In this case, the first tool cuts the threaded thread, managing 60 percent of the load, the second brings this execution to 90%, the latter completes the cutting of grooves.
This combination may change: black cuts are carried out on three quarters of the total volume of work (load), finishing. for the last quarter. At the draft cut, the picking area is noticeably longer than the final.
To prepare for cutting threads using a dick. a circular cut with an internal thread made of high.speed steel, perform several actions.
- Sip and align (if necessary) the rod or a segment of the pipe of a certain length.
- Cross the edge, on which it is first planned to perform a cut in a circle. This will facilitate the rotation of the dick, set it the right trajectory of movement. The turn is carried out at least a millimeter of the length. it has an even bevel in the context. Perfectly even turn on a lathe on a lathe.
- Squeeze a segment of the pipe or rod into a locksmith. Ideally, when the workshop of the workbench on which they are fixed is located at the level of (or just below the level) of the working belt. Check that the pipe or rod is located perpendicular to the Earth. according to the laws of physics, it is easier to start and control the cutting of the thread.
- Lubricate the inner thread of the dick and the pipe itself (or rod) with motor or transmission oil, oil waste.
- Screw manual dress holders on a dick, or install it in a low.speed machine. An ideal option will be a current machine with an adapter for a circular (machine) dress holder.
After that, put on the dick, and start rotating it around the workpiece.
Cutting the thread of the dice is carried out in a calm atmosphere, in a reliable place where the prerequisites for any random jerk action are excluded. Not installed parallel to the horizon of the dick. provided that the pipe or rod is fixed strictly perpendicular. will provide an unsuccessful start for cutting the screw groove around the chopped base. Although the dick leases itself, having passed at least a couple of turns, it is better not to allow this. the first turns will become uneven, and screw up the nut, as well as to tighten the rod into a massive detail prepared for it, it will be extremely difficult. The result is a markedly spoiled ratio of blanks that does not withstand the maximum of weight, bursting and tearing loads, which is declared according to the diameter of the “cut” blank, the dimensions of the nuts and the massive part, where this workpiece is subsequently screwed up. If the thread is spoiled, then the master will grab and scurry it with welding, which the task is set to do without starting work to create a threaded joint.
Having leveled the dick in parallel to the ground, turn it along the course of your own internal carving. A simple dick is a tool in contact with the surface of a chopped pipe or rod from four sides along the arcs of a circle, which is the surface of the workpiece on the transverse cut of the last. The equidistance of the neighboring edges (arcs of this circle) from each other and from the central axis of the pipe/rod (and the tool itself) allows the dick to move smoothly, provided that the beginning (first two turns) are clearly made.
The right thread is carried out by twisting clockwise, the left is on the contrary.
The first turns are carried out extremely carefully. the combination of cutting edges along the groove of the first turn is important, which will make it possible for the others to clearly follow the one that served the “most front”. Follow the first turn of the dick on the angle up to 90-180 degrees-you need to make sure that the process goes according to plan, the dick did not sharply turn to the side in any of the directions. If it curls, and the cutting of the thread stopped, then reach the spoiled edge by turning, and try to cut the same thread again. Even for newcomers who had never before held a dick in their hands, cutting threads quickly becomes a simple process.
Having made the first half of the turn, continue carefully, periodically returning the dick back, against the turn of the twist, move it forward in small corners. The technique is this: for example, 10 degrees go ahead. half of this angular distance (in this case, it is 5 degrees) hand back. That is, you need to cut the thread with jerks in order to prevent the overheating of the dick and the workpiece. and, as a rule, release of hardened high.speed steel, from which a cutting tool is made. Periodically remove (lead) a dick and add a few drops of machine oil to it, remove a metal chip from the tool grooves, for which a piece of rags is used.
By cutting out two turns, you can increase the intensity and amplitude of movements, for example, up to dozens of degrees. but do not overdo it: the tool and workpiece should not overheat. If this nevertheless happened, take a technological break. both a pipe (rod), and the dick should cool down.
If you cut the thread on the lathe, then turn on the reduced gear.
An attempt to twist immediately at high speed can damage the workpiece, and the dick, and the gearbox itself (or engine) of the machine. For beginners instead of a gaykovrt, they insert a suitable analogue of a machine grocery holder into a screwdriver, include the lowest speed. but before that they reinforce a screwdriver, for example, in a vice, or using brackets on a specially made elevation (support) installed on the workshop of a workbench.
Of course, you can act on the contrary. rotate the pipe by holding it in a lathe (or rod in a drill/screwdriver), and fix the dick in a vice. But this method will require a serious design of stops and guides, similar to the fact that they are used on a milling machine or a flight. Do not create additional difficulties for yourself. it will turn into extra costs for you.
Cutting the thread on one workpiece, proceed to the next. On the factory conveyor, where a constant production of the daily standard for blanks is needed, for example, a thousand rods per day, use a machine with cooling of the dick and other moving mechanisms. The cooling of the instrument that is constantly warming from friction is carried out, for example, using a technical vacuum cleaner attached to the pipe of a working (closed) compartment. You can also design a similar camera where, in addition to removing chips, which did not have time to stick to the oil supplied to the work point, the temperature of the working dick is also dumped, suppose from 100 to 150 degrees, which extends its service life. The result is neat, even blanks, as from the manufacturer. For example, this is how the end cutting of threads for studs from smooth (round) reinforcement.
Design features of the machine
The rear grandman of the lathe 1K62, consisting of a stove, a case with a landing hole and a draw.up pinoli, can move along the guides of the bed. Departure adjustment, fixing pinoli and rear center, which are installed in the rear grandmother, are carried out using a special handle. Pinoli’s landing hole has a conical shape, which allows you to fix various tools in it: drill, scan, zenker, tap, etc.
Kinematic scheme 1K62 (click to increase)
The speed box 1K62 and its back grandmother are distinguished by the simplicity of their design, the basis of which is a number of shafts (one of them is friction). On one of the shafts of the speed box there is a pulley, to which the torque is transmitted from the device electric motor. In addition, the box has a friction clutch, various blocks (triple, intermediate, etc.), supports and rolling bearings. A special oil pump is responsible for the lubrication of all moving core units.
The mechanism of the speed box
Rear grandmother 1k62
The longitudinal and transverse movement of the caliper of the machine occurs due to the running shaft and the running screw, the rotation frequency of which is regulated by the 1K62 feed box. In the design of this assembly of the machine responsible for the speed of the supply, the following elements can be distinguished: the three.stage block Nordon, shafts, switched couplings, stubborn wheels, bearings blocked together, bearings.
There is a feed box at the bottom of the equipment of the equipment, which greatly facilitates its maintenance and repair. The shaft of this box is rotated using interchangeable guitar wheels, through which it is also associated with the spindle of the device, which ensures the consistency of rotation of the spindle and feeds made by the caliper of the unit. A wheel moves along the shaft of the feed box, on one end of which there is a gear gear, and on the second. the handle, which can be installed in one of ten positions.
The device of the gearbox
The most important element of the apron of the lathe is the fallopian nut, which is in conjunction with the running screw and provides longitudinal movement of the caliper. A nut, which often fails due to wear, has the ability to self-control about the running screw, which ensures the accuracy of moving the caliper.
The apron of the machine, in which the rotation of the running shaft and the running screw is converted into the longitudinal movement of the carriage and into the transverse. the caliper, works according to the following scheme.
- Rotation from the running shaft through several sequentially located gears is transmitted to the worm wheel.
- The movement of the caliper, possible in four directions, is ensured by couplings with end teeth introduced into the engagement at the required moment.
To use the uterine nut and insert it into the hook with the running screw, the handle located on the front of the apron of the machine is used. Simultaneous involvement of the running shaft and running screw to communicate the caliper of longitudinal movement is excluded, for which a special shaft with fists is responsible.
Apron of the machine 1K62
The caliper. the most important device of the lathe. consists of such structural elements as:
Moving the carriage along the guide of the lower slopes is ensured by the screw and the silent nut. Rotation of the screw can be transmitted by means of a handle (manual control) or a toothache (automated control). On the upper surface of the carriage there are circular guides with a rotary stove. The design of this plate also provides guides, on which a four.position hazeller is installed.
The caliper of the machine 1K62
The characteristics of such a node and its design features allow you to install a rotary plate and, accordingly, a cutter with a tool at any angle to the longitudinal axis of the machine. To fix the rotary slab in the required position in the design of the carriage, special clamping bolts are provided. Use such a device if you carefully study the instructions for equipment, maybe even a novice turner.
Technical characteristics and passport of the machine 1k62
All technical characteristics of the turning and engine-cutting machine 1K62 are presented below in table format:
Characteristics 1k62. Part 1
Characteristics 1K62. Part 2
Characteristics 1K62. Part 3