GENERAL INFORMATION ON TAPPING

Tapping is a mechanically delicate machining operation :.

• There is one parameter of adjustable cutting : the number of revolutions of the tap, the advance is dictated by the thread, the cutting depth is fixed by the tool geometry.
• the tool is almost completely enclosed in the material it machines, frictions is enormous
• lubrication and cooling are random,
• The relation between the chip size and that of the tool can reach considerably unfavorable proportions in the cases of small diameters.

The tapping is an economically delicate operation :.

• The operation is slow - thus expensive
• This operation is often carried out among the last machining cycle, when the part already took value
• Any incident during the operation often has irreversible consequences or at least very deep consequences, the extraction of a broken tap is always extremely expensive.

All these characteristics affect the commercial approach.
Basic questions to ask : .

• Thread type identifictaion (metrics, UN, BS...)
• Pitch and diameter identification,
• Material to be machined,
• Characteristics of the boring to be tapped (blind or through holes, depth).
• Lubrication and cooling conditions.
• Working conditions: handbook, portable machine, device to be tapped, CNC.
• Standard.
• Tolerance.

To read a dimension : .
The coexistence of the diverse world measurement systems sometimes returns the identification of a delicate tool dimension.
If continental Europe usually measures its tools in millimeters, it is not the same for example in the Anglo-Saxon countries, which prefer the use of inches and it fractions, and to help us a little more, the inch changes its size depending on whether they are referring to dimensions for piping or for mechanical parts.