What Is a Torx Screw? Star Drive and Security Torx Explained

If you have seen a screw with a six-point star recess, you have likely seen a Torx screw. So, what is a Torx screw? It is a screw with a six-lobe drive profile. You use a Torx bit to turn the screw.

People often call this shape a star drive because of its six-lobe form. The standard Torx profile has six smooth, round lobes rather than sharp points. Other six-lobe drive profiles may look similar, but their dimensions can differ, and their tools may not be interchangeable. This shape gives the tool broad contact with the drive surface. It also helps reduce tool slip under load.

Torx screws appear in cars, electronics, furniture, tools, and many other products. Some versions also have a small pin in the center for access control.

Torx Screw Definition and Quick Answer

Hexalobular Drive Shape and Common "Star Drive" Term

Torx refers to a drive system with six rounded lobes. The ISO name for the internal profile is a hexalobular internal drive. Acument states that the TORX profile follows ISO 10664 for hexalobular internal drives.

Most people use the term "star screw" because the recess looks like a small six-point star. The term helps with visual ID, but not every star-style recess belongs to the Torx system.

A standard internal Torx tool uses a T size code. Common examples include T10, T20, and T25. The correct size depends on the drive recess, not only on the screw diameter.

What Does a Torx Screw Look Like?

Six Rounded Lobes, Internal Recess, and External Versions

A standard Torx screw has six smooth lobes inside the screw head. Look at the center of the head. You should see a balanced star-like recess with round sides.

The internal form uses T-size tools. Acument also lists external TORX forms with E-size tools. An external Torx fastener looks different. The six-lobe shape sits on the outside of the head. An E-Torx socket fits over this shape.

People sometimes confuse an external Torx head with a small hex head. Check the shape closely. A hex head has six flat sides. An external Torx has six curved lobes. Internal and external forms share the same basic Torx idea, but they need different tools.

What Is the Star Screw with a Pin in the Middle?

Tamper-Resistant Purpose and Hollow-Tip Driver Need

A star screw with a small post in the center is a tamper-resistant Torx form. Acument refers to its center-post form as TORX Tamper Resistant or RESISTORX. The center post blocks a normal solid Torx bit from full contact. You need a security Torx bit with a hole at its tip. The hole fits over the center post.

People also use names such as security Torx or pin Torx for this drive style. Check the recess before you choose your bit. If you see a post in the center, select a hollow-tip security bit of the correct size. Do not force a normal bit over the post. You risk harm to the bit or screw recess.

When selecting a replacement screw, check both the drive profile and the head dimensions to ensure a suitable fit. Explore JLCMC fastening solutions to review available fastener options for your assembly requirements.

Torx Is a Drive Type, Not a Head Shape

Examples of Head Styles with a Torx Drive

Torx tells you how the tool fits the screw. It does not tell you the outer shape of the screw head. A pan head has a low dome and a broad top. A flat or countersunk head has a cone form below the top surface.

You might also see a button head with a Torx recess. Socket-style heads also use Torx drives in some products. Acument lists Torx drive options across several head forms in its drive guide. This difference matters when you buy a new screw. You need to check both the drive type and head style.

For example, two screws might both use a T20 Torx bit. One might have a pan head, while the other has a flat head. The tool fit stays similar, but the screw sits in the part in a different way.

Torx vs Hex vs Phillips

Shape, Tool Contact, and Common ID Errors

Torx, hex, and Phillips drives have clear visual differences. A Torx recess has six rounded lobes. A hex recess has six straight sides. A Phillips recess has a cross shape. Its tool contact differs from a Torx drive.

People sometimes place a hex key into a Torx recess because both have six points. The shapes do not match. A poor fit often leads to slip or recess damage. A Phillips driver also does not fit a Torx recess. Even if a small driver enters part of the recess, the contact points do not line up with the Torx profile. Look at the recess before you apply force. A few seconds of visual check helps protect both the screw and your tool.

How to Select and Use the Correct Bit

Fit, Depth, Tool Angle, and Replacement Signs

Start with the size of the recess. Choose a Torx bit that fills the recess with little side movement. Push the bit into the recess by hand first. It should reach close to the base of the drive.

Keep the tool straight with the screw axis. A tilted tool puts more force on one side of the recess. If the bit feels loose, try another size. Do not add more force to make a loose bit work.

Check your bit for wear as well. Rounded or damaged lobes reduce contact with the screw. Look at the screw recess before reuse. If the lobes have major wear, replace the screw where the job allows. A damaged recess often gets worse after more tool slip.

People who work with several Torx sizes should keep the bits in a marked set. Clear T-size labels make tool choice faster.

Common Applications

Torx screws appear across many types of products.

People often see them in vehicle parts and other mechanical applications because the geometry supports efficient torque transfer and helps reduce cam-out. The allowable tightening torque, however, depends on the fastener specifications, the joint design, and the assembly requirements. You also see them in power tools and home appliances. Electronics makers use small Torx sizes for some devices. Furniture parts also use Torx screws where a secure tool fit helps with assembly.

Security Torx appears where product makers want to limit access with common household tools. The center post means you need the correct hollow-tip bit. External Torx also appears in vehicle work and other mechanical uses. Its socket fits over the outer six-lobe head.

Your product manual often gives the required bit size. Check the manual before you apply high force to a screw you do not know.

FAQ

Is "torque screw" the correct name?

No. Torx is the correct name for the drive system. "Torque screw" often comes from a mix-up between Torx and torque.

Is every six-point star drive the same?

No. Other six-point drive profiles exist. Similar looks do not mean the tools fit each other.

Can a regular Torx bit remove security Torx?

No. The center post blocks a solid standard bit. You need a hollow-tip security Torx bit.

Choose the Right Torx Screw and Bit

So, what is a Torx screw? It is a screw with a six-lobe Torx drive profile. You might see the drive inside the head or on the outer surface. Check the recess first. Look for the six lobes and any center post. Then choose the correct T bit, security bit, or E-Torx socket.

People get better tool contact when the bit size and drive profile match. A proper fit also helps protect the screw head from early wear.

Before choosing a replacement fastener, confirm the required drive profile, head style, dimensions, and installation conditions. Explore JLCMC screw options to compare available specifications and identify a suitable fastener for your application.