How to use a tap and die tool for threading metal?

Quick Threading FAQs

What lube to use for tap and die?

There's a lubricant specifically for this purpose. Use thread-cutting oil for creating threads with taps and dies. There are dark thread-cutting oils used for machines. But you are looking for clear thread cutting oil for slow-speed threading or hand threading.

Can you use a motor oil for threading?

Do not use motor oil for cutting threads.

Which material is durable for a tap and die kit?

We recommend HSS taps and carbon steel dies for reliable durability when threading.

Tap and die threading tools: The basics

Aaron Barnett of BangingToolbox suggests: Taps and dies are used to make both male and female screw threads. Taps and dies are used as cutting tools or forming tools for making those threads.

Taps are always used to cut and form the female part of a thread or nut, while the die cuts and forms the male end of a bolt.

With taps and dies for threading, you can make your metal working projects more functional. 

Tapping is the process of cutting and forming threads, and the die-process is better understood as threading.

Preparing the right tools

For following our how-to-use tap and die set instructions in this article. First here’s what you need to get ready.

For tapping

A tap cuts or forms a thread on the inside surface of a drilled hole, creating what’s known as a female thread on the surface that functions like a nut.

Taps allow internal threads in a hole, which allows bolts to be screwed into it. For tapping, you will need a tap wrench and tap.

Lubricating the thread can also make the process easier when cutting the threads by hand.

For threading

For threading, dies are used for making external threads on a rod.

When using the die for making a chamfer on the rod the tool will make this possible and easier for making an external thread or male thread.

Use a vise for security hold bits in place and lubrication when necessary.

Other tools needed

Cutting fluid can help to make the tapping and threading process much easier. A vise will be able to hold rods securely when threading.

What materials can you use a tap and die on?

Taps and dies were intended to be used for projects that involve metal only.

However, there are some taps and dies that can be used for projects that involve wood.

Standard taps and dies, being made for metal, can break the wood when used for tapping and or threading.

When getting a tap and die for projects that involve wood, much wider taps and dies compared to the standard metal taps are recommended especially for softer materials like softwoods.

Thread per inch: picking the size

Size of the tap (three types of tap)

In terms of the size of the tap, there are three main types of taps: the taper tap, the plug tap, and the bottoming tap. The taper tap has a visible and pronounced tapering of the cutting edges with a more gradual cutting action.

The plug tap has a less pronounced taper to the cutting edges, a cutting action less aggressive compared to the bottoming tap but more so compared to the taper tap.

The bottoming tap has 1 to 2 tapered cutting edges before the full cutting force is engaged. This is most aggressive compared to the first two.

And is good for use after cutting the initial thread.

Size of die

There are two types of die for sizing: round dies and hex dies. Round dies are made to fit in a T-handle, cutting new threads, which need a handle to be used.

Meanwhile, hex dies are used commonly used as a chaser to repair existing threads, not needing a handle, unlike the round die.

How to use the pitch gauge?

A pitch gauge is used for determining the thread pitch, checking the thread against each form by matching by aligning.

A pitch gauge has many small teeth, usually featuring a standard side and metric side.

For standard measuring, we measure the number of threads that can fit in an inch.

For metrics, we measure the distance between peaks.

To use a pitch gauge, put the teeth against the taps.

Tapping the right way

1. Preparing the hole

After making sure the pilot hole is the right size, what I find to be most helpful and efficient is to lubricate the hole or rods in order to reduce the friction when rotating the tool. Lubrication can also aid in chip removal when cutting the thread.

There are different kinds of lubricants and quality, but you can use CRC if you have it already near.

For different projects that involve different materials find a specialized product for threading.

2. Creating the thread

When creating the thread, have your tap wrench ready and on the right angle.

Proper technique is needed when using the tap and tap wrench when creating a thread so as not to break any of the thread along the way by using a backward motion as you go to break the metal filings up.

Using a flute can provide clearance for the hole. There can be metal chips that need to be blown out of the hole, you can clean up the chips with a brush, vacuum, or blower. Lastly, check that all threads work with your desired nut or screw.

Threading the right way

To use a die for threading for making external threads, prepare the rod by creating a chamfer on the end of a metal rod first [1] this can make initiating the thread easier to get started.

Make sure to then, secure the rod by clamping it with a vise.

Keep the tool and the rod level with proper lubrication.

When turning the die a full clockwise turn, make a half counter-clockwise turn in order to break up the chips produced to avoid damage.

Clean up the chips with an old toothbrush.

And lastly, check that the thread works with the right-sized nut.

How to use a tap and die set to repair a thread?

Using tap and die to repair a thread or rethread a hole or rod is similar to making a new one.

If a stainless steel bolt or nut develops rust, you can sand it clean, and rethread the join.

To repair a thread or rethread a hole with a tap and die set, spray cutting oil or lubricant on the tap.

Turn the tap clockwise around three times, and back out once clockwise to let the metal chips free to not jam or break the tap that is being used.

Make sure that the tap is as perpendicular as possible to stay even when penetrating the hole, making a new thread over the top of the old one.

Always check with your former nut or bolt to see if everything fits to confirm that nothing is loose and faulty.

Sometimes you have to step down to a smaller threaded rod or step up to wider hole sizes.

Dos and don’ts for using a tap and die

Now that you know what a tap and die set is and how to use it, here are more tips and tricks:

Dos

• Do use a tap for tapping or making holes through metal and wood.
• Do use a die for threading or adding threads to the rod. 
• Do use sharper taps and dies when working with wood. 
• Do lubricate your materials when tapping or threading [2].
• Do clear out your hole or thread by removing the metal chips. 
• Do select strong and durable taps and dies.

Don’ts

• Don’t forget to check the sizing of the taps and dies with the pitch gauge, the caliper, and the reference card.
• Don’t neglect your taps and dies. 
• Don’t force and jam your taps and dies. 
• Don’t work too fast with the taps and dies.

Time to make your own threads like a pro

Taps and dies are great and strong tools for tapping and threading, typically for projects that involve metals and sometimes wood.

The simple but effective tool can be used for making your projects more functional and complex. Being able to thread is a spiderman-like ability to stick and connect different parts of metal.

Taps are used for making threaded holes in materials while dies are used for adding threads to rods.