Torx head sizes are described using the capital letter "T" followed by a number ranging from T1 to T100.

Allen Wrench/Key Size Chart - Thomasnet Allen Wrench/Key Size Chart - Thomasnet

The development of better torque-limiting automatic screwdrivers for use in factories allowed this change.If this radial force component is too great for the material to withstand, it will cause the corners to be rounded off one or both components or will split the sides of the female part. As a result, a lower profile can be maintained for fasteners, and in some cases, the fastener can be recessed below the surface of the assembly without limiting the ability to remove the fastener. and remember, if you're not sure what you need, or which solution is best for you, our specialist advisors will be pleased to help. The "E" numbers are different from the "T" numbers of the same size: for example, an E4 Torx socket fits a T20 head. The name is shortened to IP (Internal Plus) with sizes ranging from 1IP to 100IP [18] (sometimes listed as IP1 to IP100 [19]) and EP (External Plus) with sizes ranging from 1EP to 42EP as well as smaller sizes ranging from H7EP to H2EP and includes five-lobed tamper-resistant variants.

Torx - Wikipedia

The revised design adds a further level of security and requires the use of appropriate tools that mate with the 5-point star socket and central security pin. For fixing applications they have been designed to prevent cam out and achieving the same result in regards to damage. Material options – Alloy steel is a common material used for Allen™ keys, but stainless steel is also available as a material choice. Also, inferior materials used in the manufacturing of either the wrench or the screw can render them easy to damage in spite of the increased number of pressure points.Size and weight – Allen™ keys tend to be smaller and lighter than the equivalent tools used to apply other fastener types, making them easier to carry. Torx screwdrivers have distinctive 6-point star shaped head which mate perfectly with appropriately sized screw heads. Torx screwdrivers can last up to ten times longer than regular screwdrivers due to the resilience of the design. When compared to other types of similar fasteners and the tools used to install or remove them, the hex socket type of fastener offers some advantages. This can be an advantage for applications where mobility is important such as with cyclists that might want to carry a bike tool kit along on a ride.

Ring Doorbell Replacement Security Screws (2 Pack) Ring Doorbell Replacement Security Screws (2 Pack)

Torx screws are commonly found on automobiles, motorcycles, bicycle brake systems ( disc brakes), hard disk drives, computer systems and consumer electronics. This capability provides a cleaner appearance, offers greater clearance, and protects the fastener from accidental damage. Standard Torx drivers can be used to drive Torx ttap screws, but Torx ttap drivers will not fit standard Torx screws.Security Torx has its own set of variations, and many other variations of Torx drives are available in Security or TR versions. AudiTorx is a tamper-proof fastener where a convex and smooth fastener head is topped with a break-away Torx drive that snaps off when the engineered torque is reached, leaving a rivet-like bolt head that cannot be easily removed. Rather than rely on the tool to slip out of the screw head when a desired torque level is reached (which risks damage to the driver tip, screw head, or workpiece), torque-limiting driver designs achieve a desired torque consistently. This property allows the head of the fastener to be smaller for the same required torque, which can be an advantage in applications where space to accommodate the head is limited.