How to choose the drill under the tap

When working with metal, it is often necessary not only to solder it, but also to drill it. In this case, the right tools play a huge role, and how close they are to each other. And here there is a moment how to pick up the drill under the tap, so that the work was of high quality.

Tap scheme

Tap scheme.

But at first we will sort each tool separately.

Drills: their purpose and varieties

The drill is a universal tool as it is used everywhere. Looking at what material to deal with, you can use a conical, spiral, centering, or pen-like appearance.

The most common option are twist drills. With the help of them, deep holes are created, and with the actual work process, the design of the part makes it possible to extract used shavings, which helps not to clog the working surface.

If it is necessary to process the center holes, then choose the centering type. Can be double-sided with a “tail” or with a safety cone.



When drilling pipes, steel sheets or plastic, it is best to use tapered models. In addition to drilling, such a device performs a deburring of the burrs and develops various holes. Due to this tip there is no slippage of the product.

But for work related to wood, the selection of the drill is carried out in the direction of cylindrical options. It will help to drill holes for hinges when assembling furniture, in addition, it is possible to make blind holes with a large section value.

Separately, it is worth noting products that are designed for threading, that is, in the holes after them, you can safely tighten the screws. Although a similar tool with such purpose is also a tap. But this does not mean that they are not comparable. Just under the tap and selected drills of appropriate diameters.

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Tap use: features

Set of cutting tools

A set of cutting tools: a - drills, b - countersinks, c - reamers, d - taps, d - dies.

The tap is a cutting tool through which holes are created with internal threads. Kinda it performs the function of threading.

The design of the tap is represented in two parts: cutting and tail. The first part has a calibrating and sampling fragment. "Tail" is designed to be fixed in the cartridge. With the help of the working part (screw with grooves), the hole is just drilled, while the intake part makes a thread notch, and at the expense of the calibrating part, the hole is cleaned.

The cutting of the material occurs by means of cutting feathers, which are located on the threaded part of the tap.

The grooves on the base help to remove waste material. The non-circular shape of the rear part contributes to the avoidance of friction.

Tap can be performed trapezoidal, metric, pipe and cylindrical threads. Such a process can be carried out with both hands and with the help of machines. Depending on the purpose, threads are made in one, two or four times. At this point affect:

  • hole type;
  • thread pitch;
  • necessary roughness;
  • mechanical properties of the treated metal.

If you need to work with a large thread, then pick up a few taps. Focusing on the type of work, the tool can be:

Recommended diameters of bores and rods

Recommended diameters of bores and rods.

  1. Machine-manual or just machine. Accordingly, it is used for manual or machine thread. In this case, the selection is carried out among these types: straight, screw or with shortened grooves, through which the chips.
  2. Wrenches. Intend for works under nuts. For the selection of the tap pay attention to the straight model or with a curved "tail" on the elongated.
  3. With carved thread. This is used in the processing of sheet metal or when working with ductile metal.
  4. Locksmiths The main purpose is manual cutting. They are part of the kit, which includes finishing, roughing and medium tap. Draft is used if the accuracy of cutting is not critical, the middle one corrects it, and the finishing one completes all the work. The choice of such a tap is rational when a thread with a diameter of 0.8 to 1.8 cm is needed.
  5. Conical. The intake part is not equipped with full thread, but the calibrating part is full. With this type of thread is applied to the through holes.
  6. Plochechnye. The intake cone is large. Used to create a pre-thread in the dies.
  7. Uterine. Have a spiral on the right side in the grooves. With their help, the thread is trimmed.
  8. Crankless. The receiving cone has a shorter base and there are no longitudinal grooves. Using this view, productivity increases, and the tool itself is less likely to break.
  9. Combined. Through the "neck" are connected in two parts - rough and finish. By using such a tap, the time to perform work on the thread is significantly reduced. One such example is the drill bit. They can perform and drilling, and cutting.
  10. Special. These are tools of a narrow focus. These include mounted, ship and tandem tap.
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The parameters of the selection of the drill under the tap

The drill-tap is such a tool that helps to carry out two operations simultaneously: drilling a hole and cutting internal threads on it.

In order to qualitatively carry out all the work, you need to choose the right drill. This choice is largely influenced by the required hole diameter and pitch.

There is a standard thread, from which repelled when selecting drills:

  • the size of the cutting is M2, the approximate interval is 0.45, which means that the required drill diameter is 1.5 mm;
  • M3, approximate interval - 0.5, drill diameter - 2.5 mm;
  • M4, spacing - 0.7, required diameter - 3.3 mm;
  • M5, approximate interval - 0.8, the required cross section - 4.2 mm;
  • M6, spacing - 1, the required cross section - 5 mm;
  • M7, approximate - 1.25, cross section - 6 mm;
  • M8, approximate - 1.25, diameter - 6.7-6.8 mm;
  • M9, approximate interval - 1.25, the required cross section - 7.7-7.8 mm;
  • M10, approximate interval - 1.5, diameter - 8.5 mm;
  • M11, step - 1.5, the required cross section - 9.5 mm;
  • M12, spacing - 1.75, cross section - 10.2-10.3 mm;
  • M14, spacing - 2, section - 1.2 cm;
  • M16, step - 2, section - 1.4 cm;
  • M18, approximate step -2.5, section - 15.5 cm;
  • M20, spacing - 2.5, the required cross section - 17.5 cm;
  • M22, spacing - 2.5, the required cross section - 19.5 cm;
  • M24, approximate interval -3, the value should be - 21 cm;
  • M27, step - 3, the required value - 2.4 mm;
  • M30, interval - 3.5, parameter - 26.5 cm;
  • M33, step - 3.5, the required parameter - 29.5 cm;
  • M36, approximate - 4, the necessary section - 32 mm.

In addition to the above standard requirements, there may be times when you still have to deviate from them.

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