Threading Tool

What is Threading Tools?

Threading is the process of making external threads (i.e on shafts/rods) by using a conventional lathe machine (by using a knife edge tool with zero back rake angle). for example threads on bolt. Tapping is the process of making internal threads (i.e inside or internally in the hole) by using tap set. for example the threads produced inside the nut. Moreover threading or tapping cannot be represented as forming process because while making the threads (internal/external) some amount of material will be removed in the form of chips. Therefore both are treated as cutting process only.

Taps drill, Dies and Turning Insert are some tools used to create screw threads or also known simply by threading. Many are cutting tools; others are forming tools. Taps and dies are tools used to create a screw threads, which is called threading. The process of cutting or forming threads using a tap is called tapping, whereas the process using a die or a turning insert operation are called threading.

A die cuts an external thread on cylindrical material, such as a rod, which creates a male threaded piece which functions like a bolt. Dies are generally made in two styles: solid and adjustable.

Solid dies cut a nominal thread form and depth, whose accuracy is subject to the precision with which the die was made, as well as the effects of wear. Adjustable dies can be slightly compressed or expanded to provide some compensation for wear, or to achieve different classes of thread fit (class A, B and more rarely, C).

The work piece (blank) to be threaded, which is usually slightly smaller in diameter than the die’s major diameter, is given a slight taper (chamfer) at the end that is to be threaded. This chamfer helps center the die on the blank and reduces the force required to start the thread cutting. Once the die has started it will self-feed. A periodic reversal of the die is often required to break the chip and prevent crowding.

Die nuts, also known as re-threading dies, are dies made for cleaning up damaged threads, have no split for resizing and are made from a hexagonal bar so that a wrench may be used to turn them. The process of repairing damaged threads is referred to as “chasing.” Rethreading dies cannot be used to cut new threads.

A tap is used to cut or form the female portion of the mating pair (e.g. a nut). A die is used to cut or form the male portion of the mating pair (e.g. a bolt).

Both tools can be used to clean up a thread, which is called chasing. However, using an ordinary tap or die to clean threads will generally result in the removal of some material, which will result in looser and weaker threads. Because of this, threads are typically cleaned using special taps and dies made for this purpose, which are known as chasers. Chasers are made of softer materials and are not capable of cutting new threads, however they are still tighter fitting than actual fasteners and are fluted like regular taps and dies (to provide a means for debris like dirt and rust to escape). One particularly common use is for automotive spark plug threads, which often suffer from corrosion and a buildup of carbon.

The term “Hand-Tap” has traditionally been applied to fractional size taps having a standard general purpose length. Most manufacturers don’t limit the description to fractional sizes. Assumed to be straight-flute, these are taps whose flutes are provided as a space to accommodate chips created as the tap cuts. Some research suggests the terminology originated in the early 1800’s, when most threading applications were literally done by hand. Yet, when the “Machine Age” hit it’s stride after the 1880’s, the term Hand Tap was still used for taps that were unchanged in design, and now used on machines, as well as by hand.

As “machine” tapping is a much faster operation than turning a tap by hand, chip evacuation became more difficult to control. “Machine taps” would become defined as those with flutes designed with geometry to direct the flow of chips out of the hole. Spiral-point and Spiral-fluted taps fit this category. These alterations in flute geometry improved tap efficiency. Today, with the increasing use of coolant-holes in taps, and external directional coolant-flow, a straight-flute “hand” tap can offer a similar assist with chip evacuation, and yet it is still perceived by some as different than the “machine” tap.

Both Hand Tap and Machine Taps are manufactured from the same base materials, and can be used by either method. The decision of which design to use should be influenced by the needs of the job.

The use of a suitable lubricant is essential with most tapping and threading operations. Recommended lubricants for some common materials are as follows:

Carbon (mild) steel

Petroleum-based or synthetic cutting oil.

Alloy steel

Petroleum-based cutting oil mixed with a small amount (approximately 10 percent) of kerosene or mineral spirits. This mixture is also suitable for use with stainless steel.

Cast iron

No lubricant. A low velocity air blast should be used to clear chips.


Kerosene or mineral spirits mixed with a small amount (15–25 percent) of petroleum-based cutting oil. In some cases, products such as WD-40, CRC 5-56 and 3-In-One Oil are acceptable substitutes.


Kerosene or mineral spirits.


Kerosene or mineral spirits mixed with a small amount (10–15 percent) of petroleum-based cutting oil.

Metalextra offer a complete range of Threading and Tapping tools covering all thread profiles and material groups – optimized for ISO-specific materials and optimized for flexibility.



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