Threading Tools

Threading Tools Explored

Hands up if you have been there, you are trying to cut a thread, and the tap snaps mid-turn, or you finish the job only to find the bolt does not quite fit.

If you have, you are aware that the problem with threading is not usually the metal; it is using the wrong bit of kit for the job.

As here, cutting precise threads is actually a very delicate task, and choosing incorrectly here can lead to costly scrap, wasted time, and endless frustration on your part.

It is especially trickier when you are faced with the sheer amount of options available to you - HSS, Carbide, BSP, Metric, Roll Form and more - as well as just having the technical jargon, which can also feel overwhelming.

So much so that we know how much this can slow down your work and eat into your profits at the same time. That is why we have put together this handy guide to threading tools to help you find the solution for the application you are facing.

For instance, here we will simplify the technical terms, clearly explain the difference between Taper Taps and Spiral Flute Taps, and show you exactly which standards (from Metric Coarse to UNC) you need for any material.

So stop guessing and start threading right, first time, every time.

Then, if you are still not sure in any way, our helpful customer service team is on hand to answer any questions you may have before you buy as well.

What Are Threading Tools?

Definition: Threading Tools actually constitute a category of precision instruments that have been engineered to generate or repair helical screw threads on cylindrical forms, either internally (tapping) or externally (die cutting).

As a result, here you will; find primary tools which include Taps (hand, machine, spiral flute, spiral point, or fluteless/roll form) and Dies (round adjustable or hex).

Due to this, these tools typically feature multiple cutting edges (flutes) for material removal, or use plastic deformation (forming taps) to shape the material without creating swarf.

They are also manufactured from high-performance alloys like HSS-E or Carbide, often featuring coatings such as TiN or TiCN for improved wear resistance as well.

Then, high-quality tools here will also conform to specific thread standards, including Metric ISO, Unified National (UNC/UNF), and Pipe (BSP/NPT) forms, to make sure that you get the correct mechanical interoperability that you come to expect as well.

Understanding the World of Threads

If you have ever worked with metal, wood, or even plastic, you will know that threading really is a fundamentally important process.

Simply put, threading is just the creation of a helical ridge (a thread) on the inside or outside of a component, allowing two parts - like a bolt and a nut - to be screwed together securely.

Without precise threads, your machinery just would not hold together, pipes would leak, and structures would fail.

As a result, this category of Threading Tools is actually very large and varied, but at its heart, it is all about creating these threads accurately and reliably.

Due to this, threading tools can be broadly split into two main families: Taps, which cut internal threads (like those inside a nut or a hole), and Dies, which cut external threads (like those on a bolt or a rod).

But which one is right for you?

Taps, The Art of Internal Threading

A tap is used to cut, or re-cut, a female thread inside a pre-drilled hole.

This process is actually called tapping, and if you need to attach a bolt to a component, you first need to tap a thread into the hole where the bolt will go.

There is also a huge variety of taps available, such as for instance:

Spiral Point Taps (or Gun Nose)

These are mainly for holes that go right through (through-holes), and they have a unique cutting face that pushes the swarf forward and out of the way, allowing for faster, continuous machine tapping as a direct result.

Spiral Flute Taps

These are then best for holes that do not go all the way through (blind holes), as here their helical flutes are designed to lift the swarf back and out of the hole as the tap turns, preventing it from packing up at the bottom and causing the tap to snap.

Roll Form Taps (or Fluteless Taps)

Roll form taps are different because they do not cut any material.

Instead, they cold-form or push the material into the shape of the thread, meaning no swarf is produced.

This then in turn results in a stronger thread and longer tool life, but please note: they only tend to work with ductile materials, which are materials that can undergo significant plastic (permanent) deformation, often by processes like pulling, bending, or hammering.

Cutting Taps (e.g., Hand Taps)

These then physically remove material and are categorised by their taper - Taper, Second (Plug), and Bottoming.

As a result, they are usually used sequentially for general-purpose handwork due to this.

How They Differenate From Each Other

However, threading tools are generally differentiated by how they create the thread (cutting or forming) and what they do with the metal shavings, or swarf, they produce.

The Hand Tap Family (The Set of Three)

For instance, for most general-purpose jobs, especially when tapping by hand, you will often find a set of three taps used in sequence.

They are actually designed to gradually deepen and finish the thread, reducing the strain and chance of breakage due to this.

These can consist of, for instance:

Taper Tap

This is the starting tap, and has a long, gradual taper on the end, meaning only a few threads are engaged at any one time.

Due to this, this makes it easy to start the thread straight and removes the least amount of material in one go.

As a result, this is perfect for holes that are open all the way through, or for starting a blind hole (a hole that does not go all the way through the material).

Second Tap (or Plug Tap)

Following the Taper Tap, the Second Tap has a shorter taper, usually around four or five threads, and it continues the thread, cutting deeper into the hole.

This is also the most commonly used tap for general use.

Bottoming Tap

This tap has virtually no taper at all, only about one thread’s worth, as its purpose is more to finish the thread right to the very bottom of a blind hole.

Pro Tip: You should never start tapping with a Bottoming Tap, as the sudden resistance is very likely to snap the tool you are using by doing so.

Machine Taps, Built for Speed and Efficiency

When threading is done on a machine, such as a milling machine or a CNC (Computer Numerical Control) lathe, machine taps are used, as these are designed for faster, continuous operation, and they manage the swarf differently as well.

Due to this, you will tend to see more often the following Threading tools used here:

Shank Size

Machine taps are also manufactured to precise shank size specifications to make sure that you get an accurate alignment and secure clamping in a CNC, lathe, or milling machine spindle.

Spiral Point Taps (or Gun Nose Taps)

These are common for through-holes (holes open at both ends), as the cutting edge is designed to push the swarf forward, ahead of the tap.

As a result, this is great because it prevents the swarf from clogging the flutes, allowing for continuous, high-speed tapping in turn due to this.

Spiral Flute Taps

Spiral Flute Taps are then used primarily for blind holes, as here the helical flutes (like a regular drill bit) are designed to lift the swarf up and out of the hole as the tap advances.

This then prevents the swarf from packing up at the bottom of the hole and seizing the tap, which we want to avoid occurring.

Roll Form Taps (Fluteless or Forming Taps)

These taps are then a lot more revolutionary in the space because they do not cut metal; instead they form or cold-form the thread by pushing the material into the thread shape directly.

Key Benefits of Roll Form Taps

• ✔ As no metal is cut away, there is no swarf produced, eliminating the problem of clogged flutes.
• ✔ The cold-forming process also work-hardens the material, resulting in stronger, more accurate threads as a result.
• ✔ Since the tap is not cutting, it usually lasts much longer than a conventional cutting tap due to this.

Pro Tip: Roll Form Taps require a slightly larger pilot hole than cutting taps, and they are only suitable for materials that are ductile (malleable) enough to be pushed into shape, such as certain steels, brass, and aluminium as well.

Dies and Accessories, External Threading

While taps create internal (female) threads, dies create external (male) threads, typically on rods, dowels, or bolts.

Pro Tip: As a result of this, this process is called threading (or sometimes die-cutting).

Thread Rolling

For high-volume external threading on long rods or tubing, thread rolling is often preferred.

As this method uses hardened thread rolls (instead of cutting edges) to cold-form the thread, similar to a roll-form tap.

These rollers, or diehead parts, can then sometimes be subject to reconditioning to extend their life as well.

Types of Dies

When it comes to Dies and Accessories, there are actually a lot of types of them available here, such as, for instance:

Round Adjustable Dies (Circular Dies)

These are the most common type you will find here, and are circular as well as feature a small adjusting screw, allowing you to slightly tighten or loosen the die as a result.

These features then make this brilliant for either cutting a slightly undersized thread for a tight fit or compensating for wear on the die itself as well.

Hexagon Dies (or Die Nuts)

These are then shaped like a hexagonal nut and can be driven by a standard spanner or socket.

As a result, they are primarily used for chasing or repairing damaged threads on bolts, rather than cutting new threads on raw material, as they offer you less control than adjustable dies do for instance.

Die Chasers

Die Chasers are then individual thread-cutting elements that are used in more complex, adjustable die heads, which are often seen in production environments or on pipe threading machines, especially.

Holding and Driving Tools

As you will know, a die must be held securely and driven straight onto the workpiece.

To help achieve this, this is where Die Stock (or Die Handles) come in.

As here this is the frame or holder that is used to turn the round or hexagonal die, and it features two handles for good leverage and control, which is ideal for making sure that the external thread is cut perpendicular to the rod.

Ideal Supporting Tools and Kits

Threading is not just about the tap and the die; and it requires a host of supporting accessories to make sure that you get the accuracy and safety that you need during your applications.

For instance, here you will find threading tools such as:

Tap Wrenches

You need a way to turn the tap, and this is where tap wrenches really come in, as you cannot use a regular spanner here, as this risks breaking the square end of the tap.

Due to this, there are a number of types of tap wrenches, each of which has its own needs and uses.

For instance, here you will find:

Bar Type Tap Wrench

The classic design, as it clamps onto the square end of the tap and has a long bar handle, which in turn this then offers you maximum leverage for tougher materials due to this.

T-Handle Tap Wrench

These are then ideal for smaller taps and working in confined spaces, especially as the T-Handle is often equipped with a ratchet mechanism for working in tight spots where a full turn is impossible, allowing you to turn the tap a little at a time as a result.

Plain Tap Wrenches

Simple, non-ratcheting wrenches are best suited for general-purpose use and stability.

Threading Kits

Then, for your maintenance and general workshop use, you will find Tap & Die Sets or Drill & Tap Sets, which are really invaluable for you here.

These are invaluable, as a good kit will contain a range of common thread sizes, from small Metric Fine to larger UNC/UNF sizes, along with the necessary tap wrenches and die stocks as well, all of which are neatly organised in a protective case for you as well to make your storage of them easy.

Thread Repair and Extraction

Sometimes, you will also need to fix a thread, not make a new one.

This is then where thread repair and extraction threading tools come in, such as, for instance:

Thread Repair Kits (Inserts)

If an internal thread is stripped, the classic repair method involves using a thread repair kit like Helicoil or V-Coil.

As here the process involves more drilling out the damaged thread, tapping a new, larger thread (the repair tap), and then screwing a stainless steel helical insert into the new thread.

This, in turn then restores the hole to its original thread size, often resulting in a stronger thread than the original.

Screw Extraction Tools

If a tap or a bolt then snaps off inside a hole, you will need a specialist tool to get it out.

This is where Tap Extractors really are designed to grip the snapped portion from the inside, allowing it to be carefully turned and removed as a direct result.

Indexable Threading (for Lathes and CNC)

For your production environments, indexable threading tools are also commonly used.

Here, for instance, instead of replacing an entire tool, these use small, replaceable threaded inserts or tips, and the insert is held securely in the toolholder using mechanisms like clamp style, screw lock, or a top clamp.

Pro Tip: This system is also highly cost-effective for large volumes, as you only replace the worn carbide tip when you need to, over the whole tool.

Materials, Coatings, and Thread Forms

The performance and longevity of your threading tool will also depend heavily on what it is made of and what standards it conforms to.

For instance, here you can have the following additional materials and coatings applied:

Tool Materials and Performance

The material of the tap or die will really dictate which materials it can cut successfully and how fast they can as well.

For instance, here you have:

High-Speed Steel (HSS)

This is the industry standard for general-purpose taps and dies, as it offers you a great balance of hardness, wear resistance, and cost.

Due to this, this makes these threading tools are suitable for mild steel, aluminium, and brass as a result.

HSS-E (High-Speed Steel with Cobalt)

The 'E' then stands for cobalt, which adds cobalt, significantly improving the heat and wear resistance of the tool.

This, in turn, makes it the better choice for tougher, harder materials like stainless steel, we should note here.

Powder-Met (or HSS-E-PM)

Produced using a powder metallurgy process, these threading tools then have a more uniform and finer microstructure than conventional HSS does, offering you improved toughness and tool life as a direct result - especially for precision or mass-production applications as well.

Solid Carbide

With solid carbide, you then get the hardest option available to you, and these are then used for the most abrasive or toughest materials and for high-speed machining as well.

As a result, carbide tools retain their hardness at high temperatures, but they are more brittle than HSS, so they require careful use to avoid chipping or snapping we should note.

Protective Coatings

Taps and dies are also often treated with special coatings to reduce friction, increase their heat resistance, and prolong your tool life as well.

For instance, here you can see the addition of:

TiN (Titanium Nitride)

This is then a gold-coloured, multi-purpose coating that increases your hardness and reduces friction, making it a popular choice for improving HSS performance as a direct result of this.

TiCN (Titanium Carbonitride)

TiCN then offers you the higher hardness and better wear resistance than TiN as well, making it excellent for tapping more abrasive materials as a result.

Steam Oxide/Black Oxide

A simple, low-cost coating that helps you in lubrication and prevents the work material from sticking to the tap's surface, which is particularly useful for non-ferrous metals, especially.

Understanding Thread Forms (Standards)

However, selecting the correct thread form is more than key, as using the wrong standard will result in a connection that simply does not fit or is unsafe to use.

As a result, here you have a number to choose from, consisting of, for example:

Metric Coarse ISO

The most common standard across Europe and much of the world, and it’s denoted by the letter 'M' followed by the thread diameter and pitch (e.g., M10 x 1.5).

Metric Fine ISO

These are then used when a finer adjustment or a stronger connection is needed, and they will have a smaller pitch for the same diameter (e.g., M10 x 1.0) as well.

Imperial/Unified Threads

These standards are common in older machinery and in the North American market, especially.

UNC (Unified National Coarse)

The standard coarse thread in imperial measurements (e.g., 1/2" - 13 UNC).

UNF (Unified National Fine)

Used for finer pitch connections in imperial sizes (e.g., 1/2" - 20 UNF).

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Pipe Threads

These are specialised threads designed for sealing pipes, rather than purely mechanical fastening.

BSP (British Standard Pipe)

The standard for pipework in the UK and the Commonwealth is often split into BSPP (Parallel), which requires a seal like a washer, and BSPT (Taper), which seals by thread deformation.

NPT (National Pipe Taper)

The North American standard pipe thread, also a taper form.

Thread Quality and Inspection Process

Once a thread is cut, its quality must be verified and checked, which is where Thread Gauges are used to make sure that the internal or external thread conforms to the required thread size and standard that you are aiming for.

These then include Go/No-Go plug gauges (for internal threads) or ring gauges (for external threads) to check the tolerance.

Plain Gauges are then used to check the diameter of the hole or rod before threading as well.

Pro Tip: This process is part of your calibration and is ideally needed, especially in quality-sensitive industries.

Common examples of thread sizes that are checked frequently are also the M3, M4, M12, and M20 sizes as well.

So Are Threading Tools Right For You?

As you can see, choosing the right threading tool is not just about having the correct diameter; it’s about matching the tool's capabilities to the job's demands.

As a result, you should consider the following:

Job Requirement / Material	Recommended Tool / Feature
Tough Metals (e.g., stainless steel)	Opt for tools made from HSS-E (Cobalt) and use specialist coatings like TiCN for heat and wear resistance.
High-Speed Production or Ductile Materials	Consider a Roll Form Tap to achieve a stronger thread with less swarf.
Deep, Blind Holes	A Spiral Flute Tap is essential for clearing the swarf efficiently, pulling it up and out of the hole.
External Threads (on rods or bolts)	Ensure your Die Stock is robust, and always use cutting fluid to get a clean finish and prolong the life of your die.

We hope that by now you, now understand the differences between Hand Taps and Machine Taps, the purpose of a Die, and the key distinctions between thread standards like Metric and BSP.

So much so that you should be able to confidently navigate the vast range of threading tools available to you and make sure that your threads are accurate, strong, and ready for whatever job comes next as well.

Contact Customer Support

However, if you are still not sure about which is the correct threading tool for you, or you need help, then for further product information, please contact our team, and we will be happy to help you understand which ones are perfect for you and your team.