22 Different Types of Thread Taps and Their Uses

What is Thread Tap?

A thread Taps are tools that are specifically designed to cut and restores the internal threads into drilled holes in metal part.

A tread Tap tool is used to to cut or form the female portion of the mating pair e.g a Nuts. The process of cutting and forming threads using thread Tap is called a Tapping process.

Many thread taps are manually operated using a tap handle while other automatic ones make use of drilling machines. The parts of the tap have characteristic shapes that differentiate them.

Also, threaded taps are typically made of hardened chrome steel, solid carbide, or high-speed steel. The external threads on the fasteners are made using a die.

The threaded hole and the fastener serve as a connection mechanism for parts when the use of conventional bolts and nuts is not applicable.

There is a difference between threading and tapping. Both threading and tapping produce screw threads. However, threading produces external threads whereas tapping makes internal threads.

There are many types of thread taps including hand taps, plug taps, spiral point taps, and power taps. These are just a few out of many different threads taps.

A tap is used to make (cut) new threads or clean out (chase) existing threads in a screw mechanism. Though this tool is most commonly used by machinists and engineers, automotive technicians may also have a tapping set in their toolbox.

There are dozens of situations where having solid knowledge and appreciation for the science behind tapping threads into a piece of machinery can prevent hours of troublesome work and hundreds of dollars in replacement parts.

So what are the types of taps? There are 3 main taps you should be familiar with and they are Taper, Plug, and Bottoming Taps.

What is Thread Die?

A die is a pretty simple looking tool.  It’s like a nut, but with interrupted internal threads, the edges of which are the cutting teeth.  Thread dies are often round on the outside, but they are sometimes hex or other shapes.

A die is used to cut or form the male portion of the mating pair (e.g. a bolt) and the process used to cut or form a thread using a die is called threading.

Dies are used to make external threads on a rod, creating a threaded surface that allows a bolt to be fastened to it. The die is applied to a specific diameter of rod for the size and pitch of the threads you want to cut.

An external thread (screw thread), is cut by hand with a round die that is fixed in a die stock. Round dies have three or more cutting edges, and in-between each, there are cavities which remove the chips.

Dies are generally made in two styles: solid and adjustable. An adjustable die may be adjusted either by an integrated screw or by a set of screws set in to the die holder (termed a “die stock”).

Integral adjusting screws may be arranged to work axially, where the movement of the adjusting screw into a threaded hole in the die forces the slit section of the die open, or tangentially where a screw threaded in to one side of the slit bears against the opposite side of the slit.

Threading dies are used in a variety of applications. Threading dies are commonly used in industrial metal working.

Threading dies are used for repairing threads in stripped holes or bolts. Rolled threading dies have an increased advantage of strength, longer life, and reduced material cost.

Parts of Thread Tap

Though different tap types have distinct features, the following are the main components.

Body: This is the longest and most important part. The body of a tap is what does the cutting. It contains both the thread chamfers and the full threads. The number of these varies depending on the tap type.

Shank: The shank is located just above the body. It is smooth and has a cylindrical shape. The shank length differs according to tap type. This part has marks that indicate the distance between the threads.

Tang: This is the squared-shaped part above the shank. Based on the mode of operation (manual or automatic), manufacturers fix the tang on a holder to rotate the tap.

Flutes: Flutes are grooves on taps that accommodate and expel the chips during tapping. They come in different types and shapes based on the tap type. As a standard, a tap contains 2-4 flutes which can be angular, straight, or spiral.

Land: The land is the threaded part between the flutes.

Heel: This is the slanted area behind the threads.

Cutting Face: This is the surface of the tapping tool that comes in contact with the material.

Types of Thread taps

Below is a list of 22 types of thread taps for you so that you know what they are for. With the information that we arm you with, you will have the power of making informed decisions to decide what type of thread tap you need.

#1. Hand Taps

A hand tap set is used to manually cut an internal thread. Normally, a hand tap set consists of three taps: taper tap, center tap and finishing tap.

The hand taps have a square shaft (square according to DIN 10) to be clamped securely in thread holding tools. The hand taps can be clamped in an adjustable tap wrench and holding tools with ratchet.

A hand tap is a tool used to manually carve an internal thread into a piece of material ready for a screw or bolt to be inserted in.

Hand taps are used across a variety of applications as they are multifaceted and adaptable for use by hand as well as tapping under power.

Hand taps are also used in general machine tapping and for the majority of materials that have blind- or through-hole conditions.

A key feature of the hand taps in comparison to other types of thread taps is the straight flutes to be used in either a shallow blind hole or through hole.

#2. Plug Tap

A plug tap is a type of hand tap, distinguished from bottoming and taper taps by the length of its cutting chamfer.

A 5 thread chamfer Plug tap performs similar to a Taper chamfer tap by slowly removing the material in the thread starting with the smallest diameter of the threaded protion of the tap.

Plug taps are most commonly used for through holes and where there is enough room at the bottom of a blind hole.

The rotation of the tap continues, more material is removed from the thread by many partial thread forms of the tap until a full thread is created.

There are times when a Plug tap can be used to start a thread without using a taper tap first if the Plug tap is started with a guiding center or fixture.

One of the main advantages of plug taps is that they are easy to use through holes, but provide a more complete set of threads in comparison to taper taps. However, a plug tap is not as well suited to blind holes as taper taps.

#3. Taper Tap.

The taper tap can be identified by the visible and pronounced tapering of the cutting edges. This provides a very gradual and less aggressive cutting action.

The distinct feature of a taper tap is the 8 to 10 threads that taper from the tip to the full cutting force diameter. A taper tap is most often used as a starter tap for difficult blind holes.

The gentle taper of the cutting edge is the most forgiving when tapping by hand and allows for a straight hole to be cut in especially hard materials.

A taper tap is rarely the final tap used before completing a project, however, as the taper leaves incomplete threads cut at the bottom of a blind hole.

#4. Bottoming Tap.

Bottoming taps have 1 to 2 tapered cutting edges before the full cutting force is engaged. Though this tap is extremely hard to start threads with, it is capable of cutting threads all of the ways to the bottom of a blind hole.

Bottoming taps are best used after a taper or plug tap has been used to cut the initial thread.

When rotated by hand, the bottoming taps chamfer is too short to start a thread because all the thread form would be removed with only 1.5 threads of the tap.

Bottom chamfer taps are normally used to get close to the the bottom of a blind hole but only after Taper and Plug chamfer taps have removed most of the material.

#5. Power Taps.

If you have manual matching work or CNC applications, then this is the right type of thread tap for you. The above tips are generally referred to as hand taps since they are manually operated.

During operation, the machinist must periodically reverse a hand tap to break the chip (also known as swarf) that forms from cutting. This prevents the cut material from crowding and breaking the tap.

The most common type of power-driven tap is the “spiral point” plug tap, also referred to as a “gun” tap, whose cutting edges are angularly displaced relative to the tap centerline.

This feature causes the tap to continuously break the chip and eject it forward into the hole, preventing crowding. Spiral point taps are usually used in holes that go all the way through the material so that the chips can escape.

Another version of the spiral point plug tap is the spiral flute tap, whose flutes resemble those of a twist drill. Spiral flute taps are widely used in high-speed, automatic tapping operations due to their ability to work well in blind holes.

#6. Spiral Point Taps

These thread taps have a spiral cut with relief grooves. They’re common and look like most of the hand taps you’ll see around. But, the spiral angle on the front cutting edges helps eject the chips and the angled edge also gives a superior cutting performance. 

Hence, they’re really the least expensive thread tap you might consider using for power tapping and can be run at slightly higher speeds than hand taps.

Like hand taps, spiral point taps can be had as a taper tap has a tapered end, or a plug tap (intended for blind holes) has much less taper.

They’re cheaper than the other two types, but I typically prefer the other two. The primary disadvantage of these is they push the chips ahead of the tap–down into the hole in other words. This is not a big deal for through holes but is a bad idea for blind holes.

#7. Spiral Flute Taps

Spiral Flute Taps have an open spiral just like an endmill. Their primary advantage is they eject chips up and out of the hole. They’re always preferable over spiral point taps when you have a blind hole.

They’re also preferable for an interrupted hole where another feature intersects because the spiral helps restart the threading past the open feature.

Sometimes, take a spiral flute tap and a regular hand tap and tap a couple of identical holes by hand. You’ll be shocked at how much less effort the spiral flute tap requires. Choosing the right types of taps really helps!

#8. Interrupted Thread Tap

These thread taps only have a tooth for every other thread. The idea is to provide improved chip extraction. Removing every other tooth helps break chips and also provides more room for the chip to escape and for lubricant to come in and do its job.

#9. Pipe Taps

As you might expect, Pipe Taps are the types of thread taps used for tapping pipe threads.  There are both straight and tapered pipe taps depending on whether the pipe thread is intended to be straight or tapered. The photo shows a typical NPT Thread Pipe Tap.  You can see the taper of the NPT thread profile.

Taps for tapered pipe threads have to work harder because you can’t drill a tapered hole. There’s quite a lot more material they must remove at top of the hole than at the bottom. Use a pipe taper reamer to taper the hole so the tap doesn’t work so hard.

#10. Forming tap

A quite different kind of tap is a forming tap. A forming tap, aka a flueless tap, simply forcefully displaces the metal into a thread shape upon being turned into the hole, instead of cutting metal from the sides of the hole as cutting taps do.

A forming tap closely resembles a cutting tap without the flutes, or very nearly just like a plain thread.

There are lobes periodically spaced around the tap that actually do the thread forming as the tap is advanced into a properly sized hole. The threads behind the lobes are slightly recessed to reduce contact friction.

Since the tap does not produce chips, there is no need to periodically back out the tap to clear away chips, which, in a cutting tap, can jam and break the tap.

Thus, thread forming is particularly suited to tapping blind holes, which are tougher to tap with a cutting tap due to the chip build-up in the hole. Forming taps only work in malleable materials such as mild steel or aluminum.

Formed threads are typically stronger than cut threads. Note that the tap drill size differs from that used for a cutting tap as shown in most tap drill tables and that an accurate hole size is required because a slightly undersized hole can break the tap.

Proper lubrication is essential because of the frictional forces involved; therefore, lubricating oil is used instead of cutting oil.

#11. Extension Taps

Extension taps have long shanks. This allows you to get to hard-to-reach holes. “Long shark tap” is another name of this thread tap.

#12. Punch Taps

This thread tap uses the technology of Audi and Emuge that allows tapping cycle time to fall 75%. It’s a great tool to have for your thread tapping needs.

#13. Gas Tap

A gas tap is a type of threading tap. It is commonly used to cut deep threads for merging pipes and hydraulic fittings. Gas taps are ideally suited for both conical and cylindrical shaped holes due to their one- or two-thread chamfers, unlike the much wider nine-thread chamfer taper tap.

#14. Machine Tap

Machine taps are used for threading and have grown in popularity and importance recently in line with the increased use of machinery in production.

Threading tools used in these machines are now required to be increasingly wear-resistant and durable.

Machine taps are fully automated and used in threading hard materials and are suited to both blind holes and through holes. Machine taps are used for hard materials, unlike spiral flute taps.

#15. Master Tap

A master tap is a variety of threading tap and is widely used across a range of industries. Master taps are known for their universality and diversity and are most commonly used to cut clean threads in strong and hard materials.

Master taps are similar to taper taps, however the key difference is in the number of flutes. The master tap has more cutting faces and on average 7 to 10 flutes.

#16. Combined Drill and Tap

A combined drill and tap enables the manufacturer to drill the hole and tap threads in one operation, without the need to switch tools, saving both time and money on a production drilling job.

It can be used for a variety of materials, including: aluminum, malleable iron, and brass. Similar to a spiral flute, this implement has a helical flute design.

#17. Solid Carbide Tap

Solid carbide taps are threading implements made of composite material that consists of sintered ultra-fine tungsten carbides.

They are commonly used on hard materials as solid carbide has an extremely high hardness and wear resistance. One of the key benefits of solid carbide taps is the long life span of this tool, even in more challenging working environments.

#18. Fluteless Tap

A fluteless tap is a form of threading tap that utilizes a pressure deformation technique to cut threads into a material. Fluteless taps are used only on softer metals and, unlike other forms of threading taps, the threads through the body are without flutes.

Similar to a thread-forming tap, there is no chip removal with this form of threading and this allows for high-quality threads with fast cutting speed.

#19. Machine Screw Tap

Machine screw taps are used to carve threads into the material and have on average 2–4 threads tapering from the tip. By their design, machine screw taps are used to manually thread deep holes in a variety of material types.

Manufacturers utilize the machine screw tap for routine maintenance, repairs, and rethreading in situations in which tight tolerance and accuracy are not necessary.

Unlike machine taps, machine screw taps are not fully automated—they are used alongside a tap drill machine or a manual tap handle.

#20. Stay Bolt Tap

A stay bolt tap is a type of thread tap, roughly 15–20 inches long that is designed to cut threads in drilled holes for the threaded machine screws or threaded bolts to be screwed in.

Stay bolt taps were commonly used in the application of locomotive boilers, predominantly in the repair and installation of fireboxes in steam locomotives.

The distinct feature of this thread tap is that it threads holes that match the diameter of a stay bolt nut.

#21. Bent Shank Tap

A bent shank tap is one option for thread tapping, whereby threads are cut into a material. This form of tap is used with automatic tapping machines that release nuts through the shank.

In comparison to other thread taps, a bent shank tap has the distinct feature of a bent handle extending from the tang.

This enables the tap to continuously tap, without the need to stop the drilling machine at different intervals.

#22. Form or Roll Taps (Thread Forming Taps)

Thread Forming taps don’t cut threads at all. Instead they cold form. Threads made this way are often called “rolled” threads.

With this process, the metal is pushed out of the way and compressed into position rather than being cut.  There are no chips to remove. 

As a result, the taps themselves are less likely to break and the threads they make are stronger. If your application allows Form Taps, they are generally the best thing going for those reasons.

Form Taps do require different feeds and speeds and they require a different starting hole size, so be aware of that before using one.

While many believe they’re only good for soft materials like aluminum, they can actually be used on materials up to a hardness of 36 HRC, which is about 340 BHN. That covers a surprisingly wide range of materials including a lot of steels.

I will almost always choose a Form Tap over a Cutting Tap out of the available types of taps if the material isn’t too hard for thread forming.

How to use Thread Tap and Die set for Threading?

A tap and die set is one of those toolboxes that are not immediately intuitive to have but become essential to your work once you have it.

It does not matter if you are a mechanic, a craftsman, a metal or woodworker, or even a DIY enthusiast, a tap and die set would be remarkably useful to you.

How to use a tap?

Most tapping operations are carried out manually, but power taps are electrically driven, such as the spiral point plug tap.

The tapping operation can also be machine driven by a lathe machine, a radial drilling machine, a bench-type drill machine, and similar workshop machines.

We will discuss the manual operation of using a tap since it is the most common. The process of tapping involves several steps that are described below:

Prepare the hole:

• This is the first step of tapping. It is the formation of a hole, usually by drilling, to a diameter smaller than the taps outer diameter. This diameter is called the tap drill size.
• The drill bit to be used for the hole diameter is listed in the drill and tap chart, usually inside the tap and die set. It is also available in machine shops.
• Drill the hole, either a blind hole or through-hole.
• Ensure removal of all chips from the hole.
• Select tap and ratchet. Use the chart again to select the right tap size for your project. Remember, there are different types of taps. You may have to start with a tapered tap before finishing with a plug tap.
• Depending on the tap size, use the appropriate ratchet. There are typically two sizes. Using the larger ratchet for a small tap may lead to an excessive force that can break the tap.

Create the threads (hand tap):

• Fasten down the material to be threaded with a vice or clamp.
• Insert the tap, ensure it is centered and aligned, and turn in the clockwise direction making two complete rotations. Then turn anticlockwise for half a cycle. Repeat this process until complete threading. This style of tapping prevents broken material from damaging the new threads.
• Apply cutting fluid throughout the process to reduce heat and transport chips
• Keep the material and tap centered and level.
• If you feel some restrictive force, turn anticlockwise for half a rotation and try again. Do not force the thread, or you risk breaking the tap or making incorrect threads.
• Remove the tap. Turn the ratchet anticlockwise until the tap is entirely out. The tapping process is complete.

How to use a die?

The process of threading with a die involves several steps that will be described below:

Remove the die. Turn the wrench anticlockwise until the die is entirely out. The threading process is complete.

Prepare the rod. The material diameter should be slightly smaller than the dies major diameter.The die has a chamfered side used as the entry side for the rod. The chamfer helps to center the die on the rod and reduces the start turning force when threading.

Select die and wrench. Like the tapping process, use the chart to select the right die with an appropriately sized wrench.

Create the threads. Fasten down the material with a vice or clamp.

Place the die on the material with the chamfered side starting the threads. Center the die and align it, turn in the clockwise direction making two complete rotations.

Then turn anticlockwise for half a cycle. Repeat this process until the complete threading. Use cutting fluid as required.

Tips and Techniques for Using Thread Taps Effectively

Using thread taps can be a bit challenging, especially if you’re not familiar with the process. However, with the right techniques and tips, you can create high-quality threads quickly and easily. Here are some tips to help you use thread taps effectively

#1. Use the Right Drill Size.

The size of the hole you drill before tapping is crucial. If the hole is too small, the tap will break or not thread correctly, and if it is too large, the threads may not hold. Refer to a tap drill chart to ensure you are using the correct drill size for the tap you are using.

#2. Use the Right Cutting Fluid.

Using the right cutting fluid can make a big difference in the quality of your threads and the lifespan of your tap. For example, using a lubricant like oil or cutting fluid will help reduce friction and heat during the tapping process, which can help prevent the tap from breaking or getting dull.

#3. Keep the Tap Straight.

Keeping the tap straight while cutting threads is essential for ensuring the threads are uniform and straight. Use a tap wrench or holder to ensure the tap is perpendicular to the workpiece.

#4. Use Proper Cutting Speed.

Different materials require different cutting speeds when tapping. It is essential to know the appropriate speed for the material you are working with. Too much speed can cause the tap to break, and too little speed can lead to poor thread quality.

#5. Back Off the Tap.

Backing off the tap after every turn or two can help break the chips that form during the cutting process. Breaking chips prevent them from accumulating in the hole and causing damage to the tap or the threads.

#6. Clean the Tap Regularly.

After use, clean the tap thoroughly to remove any chips or debris that may have accumulated. This helps prevent rust and corrosion, which can reduce the lifespan of the tap.

How to choose Right Thread Tap for Your Project

Choosing the right thread tap for your project is crucial to achieving the desired results. Here are some factors to consider when selecting a thread tap:

• Material: The material you are tapping into will affect the type of tap you should use. For example, a harder material like stainless steel will require a different type of tap than a softer material like aluminum.
• Thread pitch: The thread pitch refers to the distance between each thread on the tap. It is important to match the thread pitch of the tap to the thread pitch of the hole you are tapping.
• Thread type: There are several different types of threads, including coarse, fine, and extra fine. The thread type will affect the type of tap you should use.
• Tap size: The tap size should be chosen based on the size of the hole you are tapping.
• Cutting direction: Thread taps come in both right-hand and left-hand cutting directions. It is important to choose the correct cutting direction based on the type of material you are tapping into. By considering these factors, you can choose the right thread tap for your project and ensure that you achieve the desired results.

Pros and Cons of Different Thread Tap Materials

The choice of material for a thread tap can significantly impact its performance and longevity. Here are some of the pros and cons of different thread tap materials to help you make an informed decision.

• High-Speed Steel (HSS): This is the most commonly used material for thread taps. HSS taps are affordable, durable, and can be used on a wide range of materials. However, they can become dull quickly when used on hard materials like stainless steel.
• Cobalt: Cobalt thread taps are an alloy of HSS and cobalt. They are more resistant to heat and wear than HSS taps, making them suitable for use on harder materials. However, they are also more expensive than HSS taps.
• Carbide: Carbide thread taps are made from a combination of tungsten and carbon. They are extremely hard and can cut through even the toughest materials with ease. However, they are also the most expensive type of thread tap and require specialized equipment for sharpening.
• Titanium Nitride (TiN) Coated: TiN-coated thread taps are coated with a thin layer of titanium nitride. This coating increases the tool’s hardness and wear resistance, making it ideal for use on hard materials like stainless steel. However, they are also more expensive than uncoated taps.
• Powdered Metal: Powdered metal thread taps are made by compressing and sintering metal powder. They are more wear-resistant than HSS taps and can be used on a wide range of materials. However, they are also more expensive than HSS taps and require specialized equipment for sharpening.

Choosing the right thread tap material depends on the type of material you are working with and the complexity of your project.

Consider your budget, the required accuracy, and the amount of use the thread tap will endure. By choosing the right material, you can ensure that your thread taps will last longer and provide better results.

Frequently Asked Questions (FAQs)