Glossary

An industrial T-head bolt (or T-bolt) is a type of fastener with a T-shaped head, designed to be inserted into a slot or groove and turned 90 degrees to lock into place. The "T" shape allows the bolt head to sit flush or slightly recessed in the material it is fastening, providing a secure hold without the need for additional tools to hold the bolt in place during tightening. These bolts are commonly used in applications where the fastener needs to be quickly and easily inserted into a channel or slot.

Tab Locking Washers (also called tab washers or lock tabs) are specialized washers designed to prevent fasteners—such as bolts or nuts—from loosening due to vibration or rotation. They achieve this by physically locking the fastener in place using one or more bendable tabs.

A tap bolt is a type of fully threaded hex-head bolt that is designed to be inserted into a tapped (threaded) hole or used with a nut. It looks similar to a hex cap screw but lacks the washer face under the head and may not have the same tight tolerances.

A Tap End Stud Bolt is a type of stud bolt that has unequal thread lengths on each end and is specifically designed for installation into tapped (threaded) holes on one end and to accept a nut on the other.

A tee nut (also spelled T-nut) is a type of fastener used to provide a strong, reliable threaded socket in wood, particle board, or composite materials. It's especially common in furniture, woodworking, and climbing wall construction.

Teflon (PTFE) O-rings are sealing rings made from polytetrafluoroethylene (PTFE), a synthetic fluoropolymer best known by the brand name Teflon. These O-rings are used in applications where chemical resistance, high temperature tolerance, and low friction are critical.

The maximum amount of tension a material can withstand when stretched or pulled before breaking or failing. For fasteners, it determines the load they can safely support in applications where parts are pulled apart or held together under stress.

A tension control (TC) bolt—often called a twist-off bolt—is a pre-assembled structural fastener used to achieve a precise, verified clamp load in steel construction. The assembly has a round-head bolt with a splined “pintail” on the threaded end, a heavy-hex nut, and usually a washer. During installation a special shear wrench grips the nut and the spline; as the tool turns, the joint is tensioned. When the specified preload is reached, the spline snaps off at a calibrated groove, leaving a flush end and giving an instant visual check that the bolt is properly pretensioned.

TC bolts are popular on bridges and steel buildings because they’re fast, consistent, and easy to inspect. They’re generally single-use (after the pintail breaks) and require the proper wrench and procedures. In U.S. specs, common equivalents are ASTM F1852 (roughly A325 strength) and ASTM F2280 (roughly A490 strength). If you’d like, I can render a crisp, ultra-white image of a TC bolt assembly showing the splined end before and after the break.

The dimensional standard DIN 985 calls the nylon insert lock nuts in this standard as “thin” but this designation is not the same as the inch series thin nuts NTE. DIN 985 lock nuts have a thickness that is equivalent to the bolt diameter they are designed to be used on (example an M10 nut per this spec will be 10mm thick). These are called “thin” nuts because they are thinner than nylon insert lock nuts made to DIN 982 or DIN 6924. Thin nylon insert lock nuts in inch sizes (NTE series) are about half as thick as a DIN 985 nut.

A designation that defines the tolerance and fit of a thread, consisting of a number and a letter. The number (1, 2, or 3) indicates the tolerance level with 1 being loose fit, 2 standard fit, and 3 tight fit. The letter indicates the thread type, with A for external threads (such as bolts) and B for internal threads (such as nuts).

An industrial thread cutting screw is a type of fastener designed to create its own threads when driven into a material, typically metal, wood, or plastic. Unlike screws that require a pre-tapped hole with existing threads, thread cutting screws have a sharp, cutting edge or flute on their tip or threads that removes material as the screw is driven in, forming a mating thread in the process.

The distance measured between a point on one screw thread and the corresponding point on the very next thread. This measurement directly indicates how coarse or fine a thread is. For metric threads, pitch is typically specified in millimeters (e.g., an M10 x 1.5 bolt has a pitch of 1.5 mm). For imperial (inch) threads, this concept is often expressed as "threads per inch" (TPI), which is the number of threads within one linear inch

Threaded Rods, similar to studs, are three feet in length or longer. The rods can be threaded on each side or along their complete length. They are designed for tension applications and can be found in warehouse buildings. Earnest’s rods are made from carbon steel for strength and durability.

The number of threads on a fastener within one inch of its length. TPI determines the thread’s pitch and affects how tightly the fastener will hold and how quickly it will advance when turned.

A heat treatment process where the entire fastener, from the surface to the core, is hardened to achieve uniform strength and hardness throughout the material. This results in fasteners with consistent mechanical properties and improved wear resistance.

Timberjack timber screws speed installation, enter wood smoother and hold stronger than the leading timber screw. The special "U" shaped thread locks-in at the finish, reducing pull outs by 200%. Bonding timbers together stronger and reducing expensive call backs.

A Tinnerman nut, also widely known as a speed nut or Tinnerman clip, is a specialized, self-locking fastener made from stamped sheet metal. The term "Tinnerman" originated as a brand name that became a common name for this type of fastener due to its popularity. Unlike traditional nuts that require a tool to be held in place, a Tinnerman nut is designed to be easily clipped onto the edge of a panel or a stud. This design makes it a cost-effective and efficient solution for high-volume manufacturing processes.

When a screw is driven into the Tinnerman nut, the nut's spring-steel prongs are forced apart, creating continuous spring tension that grips the screw threads firmly. This unique self-locking mechanism provides excellent resistance to vibration and helps prevent the screw from loosening. Tinnerman nuts are frequently used in industries such as automotive, appliance manufacturing, and electronics to secure panels and components quickly and reliably in applications where access to the back of the material is limited.

A toggle bolt is a type of hollow-wall anchor used to fasten objects to drywall, plaster, or other hollow walls where there is no stud for direct support. It consists of a machine screw paired with spring-loaded wings that expand inside the wall to distribute the load over a wide area.

Toggle Wing Nuts are used with Machine Screws in hollow wall applications. During installation, this style of fastener is folded and then inserted into a pre-drilled hole. Once the fastener is on the opposite side of the wall, tension from the compressed wings is released, and spring open to ensure full expansion. Once the machine screw is tightened, the Toggle Wing Nut then engages the wall to provide maximum holding power in your assemblies.

A torque washer is a type of washer designed to prevent rotation or loosening of a bolt or nut by locking it in place. It typically features external teeth, internal teeth, or tabs that grip into the surface of the material or engage with a specific slot or flat edge.

A Torque-to-Yield (TTY) bolt is a fastener designed to be tightened beyond its elastic limit into the plastic range, meaning it permanently stretches slightly during installation. Instead of relying on torque alone, these bolts are tightened in two steps: first to a specified torque value, then by a set angle of rotation. This method ensures a highly accurate and uniform clamping force, making TTY bolts especially useful in critical applications such as engine cylinder heads, main bearings, and connecting rods, where consistent pressure is vital to prevent leaks or failures.

Because they are stretched past their yield point, TTY bolts cannot be safely reused—once removed, they must be replaced. While more costly and requiring precise torque-angle tools, their ability to deliver consistent load distribution makes them a preferred choice in demanding environments where reliability is essential.

A Torx bolt is a type of bolt or screw with a six-pointed star-shaped drive in the head, designed to be used with a Torx driver or Torx bit. The name Torx is a trademark of Camcar LLC, a division of Acument Global Technologies.

A fastener's ability to absorb energy and deform (change shape) significantly before fracturing or breaking. A tough material effectively resists cracks from spreading and can withstand sudden impacts or shock loads without sudden, complete failure. This property is a crucial balance between a material's strength and its ductility.

Track bolts refers to any bolts used within a tracked undercarriage system. This includes track shoe bolts, but also encompasses bolts used to secure sprockets (segment bolts), rollers, track chains, and other components of the track assembly. Track bolts come in various shapes and specifications depending on their exact function, but they all play a role in holding together the moving parts of a track-driven machine. Unlike track shoe bolts, the term "track bolts" is more general and requires context to specify the exact application.

Track shoe bolts are specialized fasteners used specifically to attach the track shoes, or pads, to the track chain of crawler-type machinery such as bulldozers and excavators. These bolts are designed to withstand heavy impact, vibration, and wear from constant ground contact. They typically feature a domed or oval head, and may include locking features like a ribbed neck or fine threads to prevent loosening under high stress. Their strength and design make them critical for maintaining the integrity and performance of the track system.

A tubular rivet is a type of rivet that has a partially hollow shank, designed to be fastened by deforming the hollow end. It is commonly used in applications where a strong but lightweight and low-profile fastener is needed.

Twin Whiz Lock Nuts offer locking serrations on both bearing faces of the nut and are designed to provide effective resistance against loosening caused by vibration. Unlike prevailing torque nuts, this style of fastener is free-spinning, allowing the nut to be threaded onto bolts or screws by hand without the need for an extra wrench during installation. Earnest Machine stocks Twin Whiz Lock Nuts in diameters ranging from #8 to 1/2” and are offered in a RoHS compliant Zinc Clear Trivalent finish.

A coarse, external thread typically found on self-tapping screws designed for use in softer materials like thin metal, plastics, or wood. Type A screws have sharp threads and a pointed tip, allowing them to tap their own threads into pre-drilled holes. They differ from Type B screws, which have a blunt point and are intended for heavier gauge metals.

A thread-forming screw with a combination of Type A and Type B features. It has a pointed tip like a Type A screw but a finer thread pitch like a Type B, allowing it to cut into thinner metals, plastics, or resin-filled plywood with better thread engagement and holding power. Type AB screws are commonly used in sheet metal and other thin materials where a balance of cutting ability and grip is needed.

A thread-forming screw with a blunt point or flat tip. Type B threads roll the thread form into the material rather than cutting it, displacing the material to create mating threads. It is commonly used in thin metals, plastics, composite boards, and non-ferrous metals such as aluminum and brass.