How to thread in hardened metal

Technology: how to use a thread tap

There are several steps, each of which is important. These are preparatory procedures, 1, 2, 3 or more approaches of rotation, finish grinding. Let’s talk more about preparation below. The manipulation of the tool itself is conventionally simple. You need to guide the tip, set it flat, and then use a turner to make a rotary motion.

  • We recommend that you do not start cutting if the workpiece is unprepared. If you already have a sheet of metal, where a through hole is obtained by punching or other metalworking, it is necessary to cut the edges, that is, countersink or reamed.
  • For a smoother run, bevel the sample at the top 0.5 cm. You have to do it at an angle of 60 degrees.
  • The tool must be lubricated and cooled in the process, otherwise you will get an additional thermal treatment, during which the metal surface may acquire additional strength.
  • Make a backstroke every 1-2 turns. This allows the working area to be cleared of chip buildup.

Watch the video. It shows not only working with a tap for tapping internal threads, but also with a die for external threads:

Tapping internal threads

When it is necessary to thread inside cylindrical parts, fasteners and mounting holes, a tap is used. It is a metal rod, the working part of which has a cutting edge in the form of transverse notches or a helical mowing line. Before threading, you drill a hole in the part, and its diameter must be 0.3-0.7 mm less than the required thread diameter (it depends on what metal you work with). A roughing tap is fixed in the tap holder and screwed into the prepared hole it removes up to 75% of the material. After that, it is necessary to go through a finishing tap, which will remove the remaining 25% of the material and bring the thread to the desired parameters.

Threading with a tap

To cut the external thread the following tools and materials are required: ram or pipe tongs, a ram, a file, a vice, a caliper, machine oil.

The most widespread are round dies (lerki). They can be made in one piece or split. Diameters of solid round dies are standardized. This allows a wide range of sizes, e.g. M10, M12, M14, M16, to be selected.

The special feature of dies is the ability to adjust the diameter of inserted thread in the range of 0,10,25 mm. However, they have lower rigidity, which affects the accuracy of the resulting profile.

Insert the ram into a ram holder of the proper size. After that fix it with screws. In the case of male pipe threads, ratchet dies are often used. They make it easy to work in hard-to-reach places, such as the wall.

Thickness of a rod is chosen on 0,10,25 mm less diameter of external thread. For example, for M6 with coarse pitch it is 5,80 5,90 mm; M8. 7,80 7,90 mm; M10. 9,75 9,85 mm. Measure with a caliper. The diameters of bars for medium metric threads of accuracy class 6g are shown in the table below.

There is a chamfer on the end of the rod to improve the penetration of the ram. Its width should be 1. 1.5 mm for M6 M18. The workpiece is lubricated with machine oil, which facilitates subsequent work and gives a better surface finish.

Cutter is placed on the end of the rod so that its plane is perpendicular to the axis of the bolt being cut. Then turn the tap holder clockwise (counterclockwise if left-hand thread is being tapped) under moderate pressure. When the die cuts into the rod by one or two threads, it should be turned back by half a turn for better chip removal. After that, 1-2 turns in the direction of the thread and 0,5 in the opposite direction are made again. Using this procedure, thread the bolt to the desired length.

The diameter of the outer thread is checked with a conventional nut or gauge ring. If necessary, the pitch can be checked with a thread gauge.

How to thread with a tap on the aluminum profile

In this article I will tell you how to thread with a tap on a structural aluminum profile. Note: when buying the 20 series (2020, 2040), I noticed that different manufacturers have different diameter of inside holes. Some have 4.2 mm holes and others have 5 mm. Accordingly, different threads are tapped and such profiles are fastened with different screws. In the profile with a 4.2 mm hole we cut an M5 thread, and in the profile with a 5 mm hole we cut an M6 thread. See the table at the end of the article

This is what I wanted to point out at the beginning of the article. Now, step-by-step instructions for threading:

A step-by-step guide on how to thread with a tapping tool in a structural profile

Tapping, Tapping Bit Holder, Lubricant, Vise, Countersink, Brush or Brush, Rag, Angle

How to tap steel | tapping steel | ultimatehandyman

Let’s fit the thread tap into the screwdriver and oil it (ideally with kerosene). We wrap the profile in rags and clamp it securely in a vise. Chamfer the edge of the hole with a countersink or larger drill bit.

Place the tap in the hole perpendicular to the workpiece. Turn the tap clockwise by pressing it. After 2 or 3 threads, we turn the tap counterclockwise by half a turn, breaking chips. Then we cut as follows: after half a turn forward, make a quarter turn backward.

After we have cut the thread to the right depth, screw a suitable bolt into the hole. It doesn’t have to screw in with force or wiggle.

And now a bit more about some of the steps. I don’t use a vice, I just hold the profile in my left hand and thread it with my right. It’s just more comfortable for me.Angle is needed at the beginning of cutting, only for the first 5-10mm pass. Threads are cut in the tube, the tap aligns itself at 90 ° with respect to the workpiece. Tapping a thread of 20 mm, I unscrew the tap several times and clean it and the hole from shavings. Aluminum is a soft metal and chips easily clogged in the grooves.

And finally, a brief table of drillable hole diameters for standard threads

thread, hardened, metal

How to thread? ?

Do not throw tomatoesI wanted to install camber plates, and the threads are not enough to put a nut.Now a question!Take it to an experienced turner?Sorry for the poor quality photo, but I think it is clear that the threads can be made and made

Комментарии и мнения владельцев 32

I wouldn’t have a problem threading it. The hardened one is nothing.everything is sharpened. The key is to know how. turner himself.

or like in the wrist to weld the diameter with a semiautomatic machine and bluntly turn and thread the same

It takes the turner 20 minutes, but everything will be straight, the fact that they are hardened is bullshit, they are only hardened on top, inside is raw dumplings. same thing happened when the special nut fell offThe photo shows it standing on the support is blurry but maybe you can see the point

My turner made it! It’s pretty quick, it’s not hard at all

I will see what my turner has to say about the rod first.If he says I’m a joker then we’ll make a nut.Thanks for the photo 🙂

To the turner of course.You can’t do it with a die and your hands

Nut threading is not an option? What the heck, grind and cut, why ruin the rod? It’s a real shame to drive around and wait for it to tear off near the weld.

About welding, I am also shocked.And about threading I just noted in the second picture is not the work surface that it would screw up

Nut should do, just above even gave a picture of how it works)

Just a man has screws with the upper cup and I have a different story without them

Grinding on a carburon and trimming with a die may not work, t.к.most likely this rod is hardened, the die from such metal will blunt in a moment and the threads will not come out. I made one of those caps. Т.е.Turn the cap with the same male and female threads and screw it on to the thread of your tap and thus increase the length. And after you have screwed the cap on the rod, I advise you to weld it with a semi-automatic welding.

On a carbaron, grind the body at the bottom to the desired diameter and tap the thread, just try to spin it evenly when you tap it)

thread, hardened, metal

How to thread with a tap: algorithm, recommendations, size tables

The question of how to thread with a tap occurs in those cases where a previously made hole must be prepared to accommodate a bolt, screw, stud and threaded fastener of any other type. Just a tap in such situations is the main tool that allows you to quickly and accurately cut the internal thread with the required geometric parameters.

Manual tapping of the internal thread is done with locksmith taps, complete with a screwdriver

How to determine the correct hole diameter?

Before threading, a hole is made, the diameter of which is determined according to standardized tables. If you prepare a hole with a cross-section smaller than the recommended value, the tool will fail, if larger the result will be of poor quality.

Table of correspondence of metric threads and hole diameters for them

Thread designation Diameter, mm Thread designation Diameter, mm Thread designation Diameter, mm
М 2 1,6 М 8 6,7 М 22 19,4
М 2.2 1,75 М 9 7,7 М 24 20,9
М 2.5 2,05 М 10 8,5 М 27 23,9
М 3 2,5 М 11 9,5 М 30 26,4
М 3.5 2,9 М 12 10,2 М 33 29,4
М 4 3,3 М 14 12,0 31,9
М 5 4,2 М 16 14,0 М 39
М 6 5,0 М 18 15,4 М 42 37,4
М 7 6,0 М 20 17,4 М 45 40,4

Table of correspondence of inch threads and hole diameters for them

Thread size, inches Diameter, mm Thread size, inches Diameter, mm
1/8 8,8 7/8 28,1
1/4 11,7 1 30,5
3/8 15,2 1 1/8 35,2
1/2 18,9 1 1/4 39,2
5/8 20,7 1 3/8 41,6
3/4 24,3 45,2

Types of taps?

As you know, there are various threaded connections in machines, equipment, machinery, and they differ not only in basic parameters such as diameter, thread pitch and depth, but also in shape, direction and type of thread. Accordingly, for each element for the application of the internal thread, it is necessary to select and tap. So let’s list the main parameters that distinguish them.

By thread direction:

  • Right-hand threads. make a groove in a clockwise direction (right-hand threads are predominant in most fasteners).
  • Left-handed. threading in a counterclockwise direction (fasteners with left-handed threads are usually installed on rotating parts so that the connection is not loosened by rotation).

According to the shape of the profile:

  • Tapered. used to create threads at fasteners where tightness is required, such as on parts under pressure of liquid or gas.
  • Trapezoidal tools are used for cutting so-called running threads, which are usually present in parts that convert rotary motion into translational motion.

In addition, a distinction is made between metric and inch taps (depending on which units of measurement indicate the characteristics of the diameter and thread pitch). As for their purpose, there are universal tools and highly specialized, designed to work with one type of part, for example, pipe, wrench, spark plug. Knowing all these parameters, you can easily choose a tap for threading in a particular part or fastener. For example, if you need to restore the thread of a spark plug seat hole in a car engine, you’ll need a tapered spark plug tap like the Jonnesway AI060001.