The tap It is a manual tool whose axis is contained in the plane and a helical path is drawn around it. This element is used to thread the female part. It can also be used for machine threading. The tap is a cutting tool with which threads are made on the inside of holes in a part, which can be made of metal or plastic.
Uses of tap
This tool is used to obtain internal threads of limited diameter. It is made up of a cylindrical or partially conical element, similar to a screw and whose thread has the same geometric characteristics as the nut with longitudinal channels for the chip outlet.
The threaded manual is used in industrial and mechanical maintenance for reworking threads, in electrical installations and assemblies. To carry out threading by hand, a series of 3 is generally used. taps in succession: the first tap has a long, completely conical entrance and lacks teeth, it is used to start and guide the thread; the second conical only at the end is used to rough the thread and the third totally cylindrical which is the one that finishes and calibrates the thread.
The threaded industrial, or serial, uses a single tap, conical at the end and cylindrical at the rest; instead it is done with machine taps. The threading is carried out on holes in parts that have been previously drilled, some with blind holes and others through. The through hole is the one that goes through all the metal and the blind is the one that has a certain depth, but does not go through the part that is being drilled. We can differentiate machine threading into two types, the first is done with taps chip starter and the second with lamination taps.
Types of taps
There are four main types of taps:
- Male with straight channel
- Male with right hand helical channel
- Left-hand helical groove tap with right-hand cutting, used to tap holes with an interrupted cut such as longitudinal holes or transverse holes. The chip goes in the direction of the advance of the male avoiding being trapped between the walls of the hole and the teeth of the male.
- Straight tap with corrected entry used in through holes, the chip is driven forward.
We must point out that the threads can present several defects: the first is associated with their calculation and design, since they may not have been selected for the dimensions of the thread, the system and the appropriate material. This produces premature deterioration.
In addition, the thread can also deteriorate through oxidation and corrosion, resulting in loss of clamping pressure and could lead to failure.
Selection of taps
When purchasing a tapBear in mind that there are different types of threads, such as BSP, NPT, BSF, BSPT, etc. and also we must know the diameter that we must make. On the other hand, and as we mentioned above, there are three numbers of taps: to start the thread, to rough the thread and finally to finish the thread.
Parts and nomenglature of taps