What tool is used for tapping internal threads
Tools for tapping
Besides the hand-held tool, small triangular thread cutting tools and taps are also used in small series production. Cutters are used for tapping external threads, and taps. for tapping the inside. A round die is shown in Fig. 2.13 and a machine tap in Fig. 2.14.
A tap is clamped in the headstock quill, giving it a manual feed.
Combination tools are widely used in high-volume and mass production (Fig. 2.15).
The materials from which picks are made have special requirements.
The cutting part of the cutter must be harder than the material hardness; strong enough because the cutting forces tend to break the cutter; tough enough because the cutting part is exposed to impact loads; resistant to wear and must retain its hardness at high temperatures for a long time, i.e.е. redness.
Tool materials must have high wear resistance, be technologically efficient and have low cost.
Tool materials are divided into the main groups.
Materials for tools working at low cutting speeds. high quality steels carbon tool steels U10A, U11A, U12A with hardness HRC 60-64 after heat treatment. Used for production of files, chisels, taps, dies etc.д.
Hardenability alloyed tool steels temperature reaches 250-300 °C, permissible cutting speeds 15-25 m/min. These steels are low-deformed during heat treating, that is why they are used for making dies, taps, reamers, drills, cutters, milling cutters, etc.д.
Materials for tools working at high cutting speeds (up to 80 m/min). high speed steels R9, R12, R6M5, R9K5F2, etc. After heat treatment these steels acquire hardness HRC 62-65; resistance to redshift up to 640°C. Tungsten steel P9 is used for making cutters, milling cutters, countersinks; P18. tools with high wear resistance (taps, dies, gear cutting tools).
Tools made of high-speed steels with wear-resistant coatings are used more extensively. Titanium nitride coatings increase tool life by a factor of 2-5.
Materials for tools working at high cutting speeds and hard alloys available in plate form.
How to cut an internal thread in 3 steps by hand
Hard alloys contain carbides of tungsten, titanium, etc., and Cobalt is used as their bond; the percentages of constituents affect the properties of the alloys.
Hard alloys have high wear resistance, hardness HRC 86-92 and red resistance (800-1000°C), suitable for speeds up to 800 m/min.
So, BK group (tungsten-cobalt. BK2, BK5, BK6M) is used for machining fragile materials (cast iron, bronze, nonmetallic materials). Fine-grained hard alloys of group B K (with index M) and coarse-grained (with index B) are designed for machining of stainless and heat-resistant steel, titanium alloys, hardened steel.
Alloy of TC group (titanium-tungsten-cobalt. T5K10, T15K6, T30K4) is used for machining ductile materials and alloys, carbon and alloyed steels.
ТТ7К12 three-carbide hard alloys have increased strength, wear resistance and toughness and are used for machining heat-resistant steels, titanium alloys and other hard-to-machine materials. Carbide inserts are mechanically fastened to tool holders and tool bodies.
Currently, 95% of cutters, 4.5% of milling cutters, 1% of axial tools are made with carbide inserts.
The tools are equipped with inserts with thin layers (5-10 nm thick) of wear-resistant materials (carbide, nitride, titanium carbonitride, etc) and have a thin washer with a nickel layer.), which increases their durability by 5-6 times.
A synthetic material is also used for the cutting part of the pick. mineral-ceramic (CM332) made from alumina (A1203), which has a hardness of up to 12 mm HRA 93, redresistant to 1200°C, very resistant to wear, but are prone to brittleness, thus limiting its use. Mineral ceramics inserts are mainly used for finishing of copper and aluminum alloys. Artificial diamonds are widely used for finishing of non-ferrous metals. No subsequent grinding is necessary when machining with diamond tools. For high performance steels, synthetic materials such as boron nitride are successfully used. Coatings, e.g. with titanium nitride, are used to improve the cutting data.
Tools and attachments used for tapping male and female threads
Special tools are used for cutting of external threads. dies. Tap is a nut with cut grooves that form the cutting edges of the tool.
Working part of the strip consists of two parts. gauge and calibrating part. The fence part is tapered with an angle of 4060º, it is located on both sides of the strip and its length is 1,5 2 threads. Calibrating part usually consists of 35 turns.
When tapping external threads by hand, different designs of dies are used: round dies, called lercuts, sliding dies (tongs) and special dies for tapping pipes.
A round die (lerki) is a threaded ring with several grooves for the formation of cutting edges and withdrawal of chips during thread cutting.
One-piece round die (flank) is fixed in the collar, using two stop screws.
Manual threading of bolts, pins and screws is done in a vice by fixing rods vertically by filing chamfer on the end face and removing scale.
Sliding dies thread the thread in two or three passes, and round. in one pass. Turn the clip with reciprocating motion of the hands. Apply moderate pressure when turning the tool. In order to keep the dies and to obtain high quality threads, the diameters of the bars to be threaded must correspond to the diameter of the thread.
Sliding dies are set in the clincher according to the numbers on the die and clincher frame. It is necessary to put a drying plate between the strip and the setscrew so the strip is not broken under pressure of the screw.
Turners for round dies are designed as a round frame with a counterbore in which a round die is inserted. The plate is held in the hole by three locking screws whose tapered shanks fit into the recesses on the forming surface of the body of the plate. The fourth screw allows you to adjust the average thread diameter.
Pipe threads are cut at the ends of water and gas pipes in order to connect them with fittings and fittings.
You can thread pipe manually using extensible and nonextensible dies attached to the dies. For threading, the pipe is clamped in the clamp, the edges of the pipe end are filed, cleaned of scale and the cut part is lubricated with olive oil.
Two sets of cutting dies. One set is designed for cutting pipe threads of nominal diameter of 15 and 20mm and the second set for 25, 32, 38 and 50mm. For threading of the pipe with 50 mm diameter the guide dies are to be changed and placed inside the clip with their short side (from the stud).
There are two standard sizes of Mayevsky tools:
Tube cluppes for tapping threads of 15 and 20 mm diameter. for 25 and 32mm diameter threads.
Thread cutting cutting cutting cutting cutting fluids are used to improve the working conditions of the tool, to decrease the roughness of the machined surface, and thus to improve the quality of the threads produced during thread cutting. Selection of coolant depends on the material of the workpiece to be machined.
A special tool, the tap, is used for tapping internal threads.
A tap is a hardened screw that has several straight or helical grooves cut into it to form the cutting edges of the tool. Chisel grooves also provide placement of chips generated during cutting, along them the chips can be carried out of the cutting zone.
Tap consists of two parts. a working part and a shank, the end of which is made a square (a manual tap).
The cutting (intake) part, which provides removal of the main part of the machining allowance;
calibrating part, which performs the final machining of the thread;
feathers (thread coils separated by chip grooves);
The core, which provides the tap with sufficient strength and rigidity for machining.
Tail part of the tap is used to secure it in the collar, which is made by working and idle movement of the tap.
The tap is fastened in the square hole of the screwdriver. The tap has four longitudinal grooves for chip evacuation and four cutting grooves. A set of three taps is used to produce a high-quality internal thread: roughing, medium, and finishing.
A roughing tap is used to set the thread in the hole.
Medium and finish taps thread to the full depth of the profile.
When threading with the tap, care must be taken that the axis of rotation of the tap aligns with the axis of the hole, otherwise the thread is tapered. Tap to be turned smoothly without jerking. A quarter-turn backwards for each revolution of the tap to break the chips. It is useful to counterbore the hole slightly to make it easier to start threading.
To thread internal threads with taps by hand, you use a device. a screwdriver, which is installed on the square end of the tail end of the tap and give it a rotary motion.
A universal screwdriver is a frame with two knuckles, a sliding knuckle and a fixed knuckle, which form a square hole. One of the handles ends with a screw that moves the slide and secures the square shank of the tap. Reliability of fastening is provided with a socket with a hole for a stopper.
Tapping internal threads
Cutting of internal threads is preceded by drilling and countersinking, and it is very important to choose the right drill of the right diameter. It can be approximated by the formula
d ws = D. P, where d ws. required drill diameter, mm;
If the diameter of the drill bit is not chosen correctly, you can not avoid defects:
If the bore diameter is larger than required, the thread will not have a full profile;
A smaller hole will make it harder for the tap to enter, which will either cause the thread to break or the tap to jam and break.
The order of tapping is as follows:
mark the workpiece and set it either on the workbench or in a vise;
drill a hole (through or to the required depth) and countersink it by about 1 mm using a 90 or 120 countersinkº;
pick up a rough tap of the required diameter with the required pitch and type of thread, lubricate its working part of oil and install it by the intake part in a hole, check its position relative to the axis of the hole with a square, put on the square of the shank screwdriver and slowly, without jerks rotate the tap clockwise to plunge it into the metal workpiece for a few threads;
further rotation of the tap should be as follows: one or two turns clockwise, then ½ turn counterclockwise (to break up chips). At the same time clockwise rotate the tap with downward pressure, and counterclockwise. freely;
threading should be performed until the working part of the tap enters the hole completely;
Turn out the rough tap from the hole and continue threading with the medium tap and then the fine tap (the fine tap must be screwed into the hole without a screwdriver. The screwdriver is put on its shank already when the tap has properly passed over the thread).
The procedure for tapping blind holes has some peculiarities:
firstly, the depth of the hole for a blind thread must be drilled deeper by 5-6 threads than it is provided in the drawing;
second, after a series of two or three working and reverse turns, the tap should be unscrewed from the hole and the hole cavity cleaned of shavings.
The quality of the cut thread is checked visually: so that there are no burrs, ripped threads and the accuracy of the thread can be checked with thread gauge stoppers for through holes and a control bolt. for blind holes.
tapping of male threads
When tapping the male thread it is important to select the diameter of the rod where the tapping is to be carried out. In the case of an improper selection, defects can occur here as well as in the case of internal threads.
The order of tapping is as follows:
select the workpiece of the desired diameter, fix it in a vise and on the end of the workpiece, designed for threading, remove the chamfer of 23 mm in width;
fix a strip (round or sliding) in a collar-plate-holder with stop screws so that the marking on the strip is on the outer side;
lubricate end of the rod (blank) with machine oil and cut at 90° angleº place a strip (marking on strip should be at the bottom);
press the strip with force against the workpiece and begin to turn the collar of the strip holder clockwise until the thread is cut to the required length. make rotary movements in the following order: one or two clockwise revolutions, ½ turn. against;
after threading to the required distance, remove the die from the workpiece by reverse rotary movements.
When threading pipes designed for pipe-laying, the order of rotary movements of the toolholder has one peculiarity. at the beginning of the thread, as usual: one or two turns forward (clockwise) and ½ one or two revolutions backwards (counterclockwise) and do not turn backwards when cutting the last few threads. The thread cut in this way has a so-called run-out, i.e. the last threads of the thread are cut to a shallower depth, which contributes to better locking of the pipeline.
To thread to a specific, fixed length, you can proceed in two ways. Either periodically measure the thread with measuring tools, or use a tool holder with a guide flange and sleeve: put the tool holder on the workpiece until the thread stops, unscrew the sleeve to the desired thread length and secure it; when the tool holder rotates, the flange will screw onto the sleeve, taking the tool behind it.
If you thread a particularly fine external thread on a cylindrical blank with a diameter of 4 to 42 mm and a pitch of 0.7 to 2 mm, you can use thread rolling dies instead of the usual dies.
In addition to the fact that such dies give a cleaner thread, it turns out to be more durable (metal fibers are not sheared during this operation, and undergo plastic deformation and sort of squeezed).
Check the quality of the cut external thread by visual inspection for broken threads or burrs. We use a test nut to check the accuracy of the thread: it must screw on without effort, but must have no backlash (swinging).
Thread cutting with a pipe tongs is carried out in the following sequence:
the tongs are put on the preparatory face of the pipe;
then the guide dies are pressed against the pipe by turning the corresponding platter secured by a clamping screw;
the cutting dies are also clamped by orienting on the risk of the faceplate;
rotate the clipper clockwise, slightly pressing it;
the threads are tapped in several steps, each time bringing cutting dies closer to each other by rotating the corresponding faceplate and the subsequent fixation with a clamping screw.
The basic tools used in tapping are taps and dies.
A handheld tap is a cutting tool designed for tapping holes. A tap is a screw that has several longitudinal straight or helical grooves that form its cutting edges. A tap has a working part I and a shank.
Tapping head is where you attach the tool in a chuck or collar while tapping 15-4186 225. Hand-held taps have a square shank end.
The working part is the tapped part of the tap that taps a thread; it is subdivided into a fence part and a gauge part.
The tapered (cutting) part of the tap is the front tapered part that first enters the hole to be tapped and performs the bulk of the cutting work. Calibrating part finishes and calibrates the tapped hole.
Hand taps are used for tapping by hand. Tapping is carried out with a set of two or three taps, depending on the thread size. A set consists of three taps for main metric or inch threads and two taps for small metric or pipe threads.
Fig. A nut-cutting tap made with an elongated shank for threading nuts on it is shown in Fig. 3, a. There are also tap and sinker taps. With a tap (fig. 3, b) preliminary (to a depth of up to 0,09 mm) threading is carried out in dies and with a master tap (Fig. 3) threads are tapped. 3, c) final (stock removal, deburring and calibration). Taps are also used to deburr the threads of dies and to clean the threads of dies in service.
The hand taps considered have, as a rule, a straight groove; in these taps, the grooves become clogged with chips during threading, resulting in increased friction of the tap against the walls of the hole. This often breaks the tap. To remove chips from the grooves in through-going thread taps in steel and ductile metalsr, a bevel is sharpened at an angle of 6° to 10° on the tapping end, in the opposite direction to the direction of the thread. Consequently, right-hand threads make a left-hand bevel and left-hand threads make a right-hand bevel. This bevel allows the chips to escape in a spiral shape through the hole drilled for the thread.
Instead of a through groove can be made on a tap and a short groove (on a length of 6-10 mm) with a slope to the axis at an angle of 9-12 °. The inclination allows the chips to come off as a long, spiral strip. Such a tap. The “rope-free” technique is used for cutting through holes. For large-diameter blind holes, taps with internal chip-removal are used (Fig. 5, в). These taps have a single no-slip groove and a hole for passing chips.
Machine taps differ from hand taps in the shape of the tail end, and through-hole taps also have a longer (up to six thread pitches) tapping end. Machine taps for tapping non-cutting holes have a short fence (up to two steps of thread).
Craftsmen thread connections using hand tools, industrial equipment. Cutting steel is performed with taps, which are fixed on special handles or machine spindles. To thread the inner side of different diameters, you need to choose dies of the right size. They are divided according to different factors, which include:
- According to the method of use. manual, machine. The first option is equipped with a screwdriver, a handle for holding. The second option represents tools that are fixed in the chucks of industrial equipment.
- According to the method of cutting the inner coils on the metal, complete, universal taps are distinguished. The first are tools, the working part of which is divided into 3 zones. The former do the roughing, the latter bore out the grooves, the latter bring the surfaces to the finish state. The second option is a set of individual taps, each for a specific application.
- The division by type of hole. There are tools for working with blind and through holes. The first variant has a long rod that has an elongated tapered shape, called a lead.
Taps are divided by design. They can be straight, helical, and with cut grooves to remove metal chips.
Taps are used to create metric threads. In addition, they can be used for inch, pipe threading. The shape of the tool can be tapered or cylindrical.
THREADING AND THREADING TOOLS
Thread-cutting is the formation of a helical surface on the outer or inner cylindrical or [-tonic] surfaces of a workpiece.
Which tools are used for cutting a helical surface on the external cylindrical surface of a workpiece??
Threading on bolts, rolls and other outer surfaces of parts can be done manually or by machine. Manual tools include: round chisel and non-cutting dies as well as quadrilateral chisels. and hexagonal inserts, tubing tongs for tapping threads. Dies are fastened using tool holders and tongs. The round die is also used for machine tapping.
The number of tap holes d depends on the thickness of the chip azt removed by the teeth of one hole, the angle of the taper f and the thread pitch t:
The greater the number of holes on the hob, the thicker the cossette material, the finer the cossette material and vice versa.
Depending on the diameter of the thread to be tapped, the number of holes ranges from 3 to 14.
Tapping of external threads by machine can be done on lathes with thread cutters, chasers, threading heads with ra. 76 diagonal, tangential and circular combs, whirling heads, and on drilling machines with thread cutters, on milling machines with thread cutters, and on thread grinders with single- and multi-strand wheels.
Obtaining the outer thread surface can be accomplished by rolling it with flat dies, round rollers on thread rolling machines. Threading Applications. Axial feed head taps are used for tapping external threads on drilling and turning machines.
Name a tool for tapping holes.
Threading of holes with taps is done manually and mechanically. A distinction is made between cylindrical and tapered taps. Hand taps are single, two-piece, and three-piece. Usually a set consisting of three taps is used: a roughing tap marked with one line or the number 1, a middle tap marked with two lines or the number 2, and a finishing tap marked with three lines or the number 3 (tab. 12, fig. 29).
As calibrating and running taps
For 6-24 mm coarse pitch metric threads For x/4-2″ inch threads For 4″ pipe threads
For coarse pitch metric threads in 24 to 52 mm diameter For difficult-to-tap metals regardless of thread diameter and thread type
Special taps are available for taps (tap taps with a long cutting edge), nuts, pipes, light alloys, and tapered taps. Taps can be used to tap threads in through holes and blind holes or to calibrate previously tapped threads with a master tap. 77
A screwdriver with a fixed or adjustable square hole is mounted on the shank of the hand-held tap ending in a square head.
Combination taps that can be used for drilling and tapping are used in some cases.
Machine taps are used for tapping internal threads on all types of drill presses and lathes. They can be used to threaded in one or more steps
Passes. Threads with a pitch of up to 3 mm are tapped in one pass, and threads with a larger pitch, particularly long threads, and smooth threads in hard-to-tap materials are tapped in 2-3 passes, regardless of the pitch.
Nut taps are used for tapping nuts on machines. They operate without reversing and thread the nut onto the shank when threading. A distinction is made between straight shank and curved shank taps.
Threading heads with adjustable combs or converging dies are used for cutting large-diameter internal threads.
Tapping elements. the working part, which consists of a cutting and gauging parts and a shank. The T8 working part has a spiral thread and longitudinal grooves to remove chips. The cutting edges are obtained at the intersection of the spiral rifling and the longitudinal grooves for chip removal. The tail ends with a square head for insertion into the chuck. Taps are made of carbon tool steel U12 and U12A, high-speed steel R12 and R18, alloyed steel X06, XB, TX.
What is a helical surface?? A helical surface is a surface described by a curve that rotates uniformly around a
The axis and at the same time making a uniform translational motion along this axis. A thread surface is a triangle (for metric and inch threads), a trapezoid (for trapezoidal threads), or a rectangle (for rectangular threads, such as in jacking screws).
A thread profile is a contour obtained by dissecting the helical surface by a plane passing through the screw axis.
A thread profile consists of the protrusions and depressions of the coils. The axis of the shaft is the axis of the helical surface
What parameters define a thread in each screw and each nut?
The parameters of threads are the outside diameter d, inside diameter du, middle diameter d%, pitch I, thread profile angle os. The thread profile is divided into two parts: protrusions and troughs. Threads may be single threaded and multiple threaded.
The thread pitch should be understood as the progressive movement of the center point of the formative profile, corresponding to-
corresponding to one complete revolution of the thread in relation to the thread axis.
The thread pitch is defined by the distance between the axes of two identical points of one thread turn after another. or by the distance by which the nut is moved on the screw during one complete revolution for a single thread (tab. 13 и 14).
What is the stroke of a multi-turn thread?
The helical surface of a multiple thread can be thought of as several helical grooves having
A. triangular; b. trapezoidal symmetric; c. trapezoidal asymmetric; d. rectangular; e. semi-circular.
The nominal diameter (and therefore one nominal pitch, which in multi-tap threads is called a t-tap) and formed on one smooth cylindrical surface with evenly spaced runs around the circumference. Thus, the thread stroke t is the distance between the nearest homonymous sides of the profile, belonging to the same helical surface, in a direction parallel to the thread axis. Thread stroke is the relative axial movement of a screw or nut per revolution.
What is the relationship between threading stroke and thread pitch?
If the thread is single threaded, the thread stroke t equals the thread pitch P. If the thread is multi-tapped, the thread pitch t is equal to the product of the pitch P by the number of starts n:
Creating a thread with a cutter
Special picks are used for turning on the lathe. They are of the following kinds:
Their characteristics must comply with GOST 18876-73. The upper part of the pick which is in direct contact with the metal to be cut must correspond exactly in shape to the slot being produced.
Prismatic and bar threads are used to cut the outer threads. There are disc threads for both male and female threads. Multi-field tools, which cut several grooves at the same time, are used on a lathe.
Cutters made of sintered carbide are installed on shank cutters. They retain their sharpness for a long time and practically do not need sharpening. If they lose their sharpness, the cutting part is usually replaced. Prismatic picks differ from solid picks in that they make contact with the metal over a wide area. They tend to lose their sharpness very quickly during use and need to be sharpened periodically.
Cutters can have design differences. They can be of the following types:
The straight shape is rarely used on a lathe. Bent picks are the most frequently used for thread-cutting.
Made of alloyed high-speed steel.
Using soldered carbide inserts.
It is possible to use replaceable multifaceted blades. After the cutting part is ground, the other working face of the pick can be used.
There are cutters, for the production of which cermet is used.
In the first case parts made of steel, plastic or non-ferrous metals are usually machined. Cutters are characterized by particularly high strength and high thermal conductivity. But they have the following disadvantages: poor wear resistance, insufficiently high hardness. These qualities limit the speed of machining parts when creating threads on the machine.
Carbide-tipped cutters are most commonly used. They are known for their high hardness and long service life without the need for sharpening. the maximum cutting speed is 2-3 times higher comparing to high speed steel cutters. Such cutters are available in a wide range of products, making it easy to select the appropriate one for a specific job.
Ceramic metal cutters are cheaper. Their main disadvantage is brittleness. Their main application is the creation of fine threads on workpieces made of steel and cast iron.
Cutters with cutting parts made of polycrystalline diamond or cubic boron nitride are highly durable. They are used for precise threading on workpieces of high-strength parts. The main disadvantage of such tools is their high cost. In the first case, such tools are used for machining aluminum, copper or tungsten carbide parts. In the second case, such tools work on workpieces made of hardened cast iron or hardened steel.
The following special features must be taken into account when working with cutters:
The selection of the rake angle is important. Its value depends on the hardness of the material being cut. The value is within the range from 0 to 25 degrees from perpendicular to the machined surface. A zero angle is chosen for normal steel, but for high-alloyed steel a 5-10 degree angle is usually required. Its value depends not only on the hardness but also on the toughness of the material to be machined.
When selecting the right pick, it is important to remember that the shape of the cutting edge has to correspond exactly to the thread profile.
The trailing lateral corners must be narrow enough so that the groove made by the chisel is not affected. They must be the same on both sides.
To thread a part internally, the part is drilled and bored beforehand.
Threading takes place at high speed. The work can also be done on a CNC machine.
Types of pipe threading tools
Parts and elements with threading are used in various areas: construction and sanitary engineering, industry and mechanical engineering, on the joinery. In this article we will look at tools for tapping pipe and round workpieces. Depending on the frequency and quantity of work, a distinction is made between handheld and power tools for tapping.
The tools shown in this section are manufactured by the following companies:
Threaded connections are widely used in the construction of machines, devices, instruments and appliances of various industries.
The basic method of thread production is threading on external surface (with tap, turner, thread cutter or cutter) and on internal surface (with tap, thread cutter or chisel) of the parts. Internal threads can also be obtained by plastic deformation by rolling, for this purpose tapless taps (rolling taps) are used. Their main difference from cutting taps is the absence of chip grooves.
Thread cutting tools are divided into metric, inch and pipe threads according to the profile of the thread to be tapped. Each sub-section contains several dozens of thread profiles for different applications.
Metric threads with pitch and basic parameters8 of threads in fractions of a meter. Metric taps and dies are commonly used with nominal diameters of 1 to 600 mm and pitches of 0 to 6 mm.25 to 6 mm and have a profile. Equilateral triangle (apex angle 60).
Inch thread All thread parameters are expressed in inches, pitch in fractions of an inch (inch = 25.4 mm). inch taps and dies are used for this thread type. Depending on the pitch, inch threads are subdivided into: UNC (Unified Coarse); UNF (Unified Fine); UNEF (Unified Extra Fine); 8UN; UNS (Unified Special). Inch taps and dies are common in the United States and have an apex angle of 60.
Pipe threads are commonly used in two kinds, cylindrical threads marked G and tapered threads marked R.For inch pipe threads, the inch size is a notional measurement of the clearance in the pipe, while the outside diameter is actually much larger.
There are cases when it is necessary to tap threads which do not fit into any of existing standards. In such cases special taps and dies are used, which are made according to drawings and have special parameters. Special taps and dies allow us to form threaded connections that meet the requirements of special parts as much as possible.
Hand taps are the most common type of threading tool for producing internal threads in pre-drilled holes. Handheld taps have straight grooves to remove chips from the cutting zone. They can be used for both machine tapping and hand tapping. Hand taps are available for tapered, through and blind holes.Machine taps are thread-tapping tools for forming inside thread shapes on machine tools. They differ from handheld taps in special geometry that allows you to increase the productivity of the threading process by several times.
dies and lerks. Threading tool for tapping external threads by hand or machine. The division into dies and lerks no longer exists today. Previously, the name die was used for set and adjustable threading tools, preferably of large diameters. The term lerka was used to represent a plate with a threaded hole and grooves for chip evacuation. Lerks were used to make finer threads of smaller diameters.
Thread gauges are used to control the resulting thread profiles and are divided into several types. Internal threads are monitored with the Caliber plug, which has two sides. one through (to monitor the lower dimension deviation) and one not through (to monitor the upper dimension deviation). which together allow you to check the thread size accuracy within the tolerance zone. To control external threads, thread gauges in the form of Calibre-ring are used. The set consists of two calibrating rings, the first one through (to control the lower dimension deviation) and a non through (to control the upper dimension deviation). The threaded gauges supplied by Vetka can be supplied with an international certificate.