Which hand tool is used to form internal thread in a hole?

Concept:

Tapping:

• It has been defined as a process for producing internal threads using a tool (tap) that has teeth on its periphery to cut threads in a predrilled hole.
• A combined rotary and axial relative motion between the tap and the workpiece forms threads.

Reaming:

• The process of enlarging the hole is called reaming.
• A reamer is a type of rotary cutting tool used in metalworking.
• Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides.
• There are also non-precision reamers which are used for more basic enlargement of holes or for removing burrs.

Drilling:

• It is a cutting process that uses a drill bit to cut a hole in a circular cross-section in solid materials.
• The drill bit is usually a rotary cutting tool, often multi-point.

Scrapers:

• The mechanical scraper tool is made up of old files and the cutting edge of the scraper is hardened and tempered.
• They are mainly used to scrap metal surfaces by rubbing the work surface.

The following types of scrappers according to shape are commonly classified as

• Flat
• Hook
• Triangular
• Half-round

• From the above definitions, we conclude that Reaming is performed after a hole already exists and it is done for providing a good surface finish and accuracy.
• So, it can be performed after drilling, boring, and counterboring but cannot be done after Tapping. 
• As in tapping, we create internal threads in a predrilled hole so if after tapping reaming is done then it will lead to the destruction of the internal threads as the reamer flutes move across it which is not desirable.