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Screwing Taps 
A rotating tool to screw thread in holes, consisting essentially of a threaded body having two or more straigth or helical flute, or without the flute having lobes, intersecting lines with the threaded body of which form the cutting profile of the tool. It is provided with a shank and a driving square for holding and driving.

Types of Screwing Tap
Cut Thread Screwing Tap: A screwing tap in which the threads on the body are formed by cutting or rolling, while the screwing tap blank is still in unhardened condition.
Ground thread Screwing Tap: A screwing tap in which the threads on the body are finshed by grinding, When the screwing tap blank is in hardened and tempered condition.
Serial Screwing Tap: A set of two or three screwing taps with identical general dimensions but progressively increasing major diameter and varying chamfer lengths. They are designated as Rougher, intermediate and Finisher screwing taps.
Non-serial Screwing Tap: A set of two or three screwing taps with identical general dimensions and varying chamfer lengths. They are designated as Taper, Second and Bottoming screwing taps.
Hand Screwing Tap and Short Machine Screwing Tap: A screwing tap with shorter shank length for general purpose. These screwing taps can be used for manual tapping as well as for machine tapping.
Long Shank Machine Screwing Tap: A screwing tap with longer shank length for longer reach, to be used for machine tapping.
Right-Hand Screwing Tap: A screwing tap which cuts while rotating in clock-wise direction when viewed from the shank end of the screwing tap.
Left-Hand Screwing Tap: A screwing tap which cuts while rotating in anti-clockwise direction when viewed from the shank end of the screwing tap.

Types of Ground Thread Taps

Straight Fluted Tap:


This regular basic tap is designed as a general-purpose tool for hand and machine operation. This basic tap will give acceptable performance in most materials and for short production runs. Straight Fluted Taps are usually the most economical tap to use. However, it performs best in materials where the cutting action results in chips, which break us readily and do not present problems of chip disposal.

Spiral Pointed Tap:


Spiral Pointed Taps (also known as Gun pointed taps) are intended for machine use. These have straight flutes and supplement angular flutes (at point), Which are in the opposite direction to that of cutting. In their usual from they have a second tap lead, this design propels the ahead of the tap, leaving the flutes clear for the free flow of coolant to the point.

Designed mainly for use in through holes, these taps can be used in blind holes provided there is ample clearance after the threaded section of blind hole.

The advantages of a gun tap are:
The shearing action of the angular cutting faces produce a fine finish on the threads.
A shallower flute achieve a stronger cross section, and allow the tap to withstand higher cutting force and torque.


Spiral Flute Taps:





These taps are designed primarily for machine tapping of blind holes. They are used to the best advantage in soft materials such as aluminium and steel, which produce long, stringy chips. The shear action provided by the spiral flutes draws the chip out of the hole allowing greater depth of threading without chip clogging.

Pipe Taps (Parallel):


These taps are generally used for pipe fitting and coupling, as their name implies. The norminal size of a pipe tap is that of the pipe fitting and not the actual size of the tap.
British Standard :- BSP
American Standard :- NPS


Pipe Taps (Taper):


These taps are used for taper threading required in pressure tight joints for fluids, gas etc.
British Standard :- BSPT
American Standard :- NPT


Machine Nib Taps:

Special designed taps, to give perfect thread in Nuts; used extensively in Nut manufacturing industry.


Roll Taps (Fluteless Chipless Tapping):







These taps are designed for machine tapping in ductile materials. " Roll Taps " have no flutes or cutting faces, but have special roll forming lobes with circular lands and have short taper leads for through or blind holes.
Since the displacement of metal has to be considered, specially calculated tapping drill sizes are necessary.
Some of these taps have Oil Groove for the lubrication purpose.



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