Glossary

Hammer drive anchors are versatile fasteners used in various building materials such as concrete, brick, mortar, and cement blocks. This fastener consists of a slotted, cylindrical body with a nail protruding through its center; these anchors are installed by inserting the fastener into a pre-drilled hole and then driving the nail down with a hammer. The expanding sleeve grips the surrounding material tightly, providing a reliable and strong attachment point for fixtures, brackets, or other items in a wide range of applications.

A hanger bolt is a type of fastener with wood screw threads on one end and machine screw threads on the other. It’s designed to secure objects to wood while also allowing a nut or other threaded part to attach on the exposed end.

Hardened Square Washers, I-Beam Hardened Washers, and Tapped Hardened Washers all describe Bevel Square Washers. Earnest’s through-hardened Bevel Square Washers are used on I-beam construction to build bridges, buildings, and warehouses. These special washers match the angle of the top and bottom I-beam faces to create a parallel fastening surface.

A hardened flat washer is a type of flat washer that has been heat-treated or hardened to increase its strength and durability. These washers are used to distribute the load of a fastener (such as a bolt or nut) more evenly over a surface and are designed for use in applications where high levels of stress, load, or wear are expected.

Plow Bolt Washers are through hardened for Grade 8 or better applications — preventing imbedding or distortion to the washer and material being clamped. The washers provide a smooth, level protective bearing surface to tighten nuts and bolts. For added strength, Plow Bolt Washers are thicker than standard USS washers for more demanding heavy-duty applications (plows). Earnest offers the washer in a corresponding Grade 8 or better strength.

The measure of a material’s resistance to deformation, scratching, or indentation. In fasteners, hardness level indicates how durable the surface is and how well it can resist wear and damage over time. It’s usually shown as a number based on standardized tests like the Rockwell, Brinell, or Vickers scales.

Earnest Machine Products line of B7 Heavy Hex Cap Screws are manufactured to the material and physical properties specified by the American Society for Testing and Materials standard ASTM A193 for Grade B7. The overall dimensions are made to the requirements of ASME B18.2.1 for heavy hex cap screws.

Otherwise known as Heavy or Heavy Thin Nuts, Heavy Hex Jam Nuts are half as small as Hex Nuts. They resemble Hex Jam Nuts; however, they’re larger across the flats. These nuts are generally used to bolt light poles and electrical lines. Earnest carries a full line of Heavy Hex Jam Nuts in Grades 2, 5, 8, and A194 2H.

Heavy Hex Nuts, or Structural Nuts, hold the world together — in charge of securing together buildings, bridges, and warehouses. Their job is to bolt I-beams to one another in order to raise structures. Heavy Hex Bolts provide a greater width across the flat compared to Finished Hex Bolts for a dispersed clamping load. Earnest offers Grades 5 and C, also available in lefty threads.

An industrial heavy hex slotted nut is a specialized type of nut designed for high-strength fastening in heavy-duty applications. It combines the characteristics of a heavy hex nut and a slotted nut (also known as a castle nut). These nuts are used in situations where a secure and locked fastening is critical, often in conjunction with a cotter pin or locking wire.

Heavy Square Nuts, like their smaller counterpart Square Nuts, are widely used in the locomotive industry. They are designed to have a larger square — increasing the bearing surface size. Earnest provides these classic-looking nuts in Grades 2 and 5 for durability and ductility.

A helical screw insert, also known as a helicoil (a brand name), is a threaded wire coil used to repair or reinforce tapped holes in metal, plastic, or composite materials. It creates strong internal threads for bolts or screws, especially in softer materials like aluminum or magnesium.

Heavy Helical Spring Washers, or Heavy Helical Spring Lock Washers, are designed to prevent loosening in vibrating applications. The circular coil grabs onto the head and material being fastened, creating a locking action. Heavy Helical Spring Washers are through hardened with a large width to improve strength and performance. Heavy lock washers are for use in Grade 8 or better applications.

Light Helical Spring Washers, or Light Helical Spring Lock Washers, are designed to prevent loosening in vibrating applications. The circular coil grabs onto the head and material being fastened, creating a locking action.

A Helical Spring Regular Lockwasher, commonly known as a split lock washer, is a type of washer used to prevent fasteners like bolts or screws from loosening due to vibration, movement, or torque. The washer is designed with a helical (spiral) shape that provides a spring action when compressed. This spring action helps maintain tension on the fastener, locking it in place.

A hex bolt is a type of fastener with a hexagonal (six-sided) head and a partially or fully threaded shaft. It is designed to be used with a nut or tapped hole and tightened using a wrench or socket.

Castle Nuts, or Slotted Nuts, resemble Hex Slotted Nuts; however, the tops of the their corners are machined off for better cotter pin fitting. The design prevents the nuts from loosening in rotating applications such as bearings and bushings. Earnest offers the nuts in Grades 2 and 5.

A hex castle nut DIN 935 is a type of fastener designed to be used in applications where a secure, locking connection is needed, typically with a cotter pin or wire. The DIN 935 standard refers to a specific German (Deutsches Institut für Normung) specification for castle nuts, ensuring uniform dimensions and manufacturing standards.

Coil Nuts, or Hex Coil Nuts, are used with Coil Thread Hex Bolts and rods for quick assembly and disassembly of concrete forms. With their special wide design and rounded root coil, the nuts are self-cleaning. Coil Nuts are used in the construction industry to help build concrete sidewalks, roads, and buildings.

Hex Coupling Nuts are made from carbon steel and are designed for use with threaded rod studs. These fully threaded Hex Coupling Nuts are used to attach two lengths of rods together to form a long, secure thread length.

Flange Screws, Hex Flange Bolts, or Frame Bolts are designed with a built-in washer underneath the head of the bolt — distributing the clamping load over a wider area. This eliminates the need for a separate washer, as it provides the same holding power. Engineered with quality in mind, Earnest’s Flange Bolts are made to Property Class 10.9 standard to provide the durability and strength. These two-in-one bolts are popularly used to secure truck frames with ease, as well as many other applications.

Commonly used to secure components to truck frames, Hex Flange Screws offer a built-in flange that distributes the clamping load over a wider area, eliminating the need for a separate washer. Earnest Machine stocks a large selection of high-strength, inch, metric, and JIS hex flange screws ready-to-ship the same day.

A hex lag screw, also known as a lag bolt, is a large, heavy-duty screw with a hexagonal head, designed for securing heavy materials such as wood, metal, or masonry. Unlike traditional screws, lag screws require pre-drilled holes and are commonly used in construction, woodworking, and outdoor projects where strong, durable fastening is necessary.

Hex Serrated Flange Screws offer a locking head design with built-in serrations on the bearing face of the flange. These serrations allow the screw to lock onto its installation surface providing excellent resistance to loosening due to vibration. Earnest Machine offers Hex Serrated Flange Screws in both standard and large flange diameter styles.

Hex Flange Nuts resemble Hex Flange Bolts. Likewise, Hex Flange Nuts, or Frame Bolt Nuts, have a washer attached to the head of the hex body. These free-spinning nuts incorporate a large bearing face to eliminate the need for washers. They are often found in truck-frame assemblies. Earnest offers Hex Flange Nuts in a Grade 8 to provide strength and toughness.

Hex Flange Nuts offer a unibody design that eliminates the need for a separate washer. The built-in flange distributes the clamping load over a wider area and reduces the risk of loosening due to vibration. Earnest Machine stocks Hex Flange Nuts in both inch & metric in sizes from 1/4" to 1" & M4 to M20.

Commonly used to secure components to truck frames, Hex Flange Screws offer a built-in flange that distributes the clamping load over a wider area, eliminating the need for a separate washer. Earnest Machine stocks a large selection of high-strength, inch, metric, and JIS hex flange screws ready-to-ship the same day.

Hex Head Bolts are standard bolts. They have a wide variety of applications for maintenance and repair workers. A correct shoulder length will provide added strength compared to a fully threaded bolt, however, restricting its versatility. Earnest’s unique line of Hex Head Bolts are offered in hard-to-find sizes in Grades A, 5, and 8 (BD) to ensure the proper strength in every application.

Hex Head Cap Screws are designed with a washer face under the head to provide uniform torque tension, meaning you can assemble this product by tightening the head of the screw or by tightening a nut onto the threads of the screw. Earnest Machine stocks this style of fastener in diameters ranging from 1/4” to 3” with lengths ranging from 1/2” to 20” with a wide selection of grades and f inishes to choose from.

A Hex Head Cap Screw DIN 931 is a type of fastener that is partially threaded, featuring a hexagonal (six-sided) head, and conforms to the DIN 931 standard, which specifies the dimensions and requirements for metric hex head cap screws. These screws are used to secure two or more components together in mechanical and structural applications.

A Hex Head Cap Screw DIN 933 is a type of fully threaded fastener with a hexagonal head, conforming to the DIN 933 standard. This standard specifies the dimensions and mechanical properties for these screws, ensuring consistency and reliability in various applications.

Used in the construction industry, Concrete Form Bolts, or Form Bolts, help build concrete walls, sidewalks, roads, and buildings. Their special thread design allows the ability to assemble and disassemble concrete forms with ease. The “coil” thread, a special wide thread with a rounded root form, is designed to be self-cleaning while it’s unthreaded — good for multiple uses.

Saddle Bolts, Suspension Bolts, Suspension Saddle Bolts, or Truck Suspension Bolts all describe the bolts used for truck suspensions. Commonly used in Mack trucks, these bolts are used in truck suspension assemblies. Earnest carries a Grade 8 for added toughness to withstand heavy loads.

Earnest's line of structural fasteners are manufactured to the requirements of ASTM for use in the construction and remodeling of buildings, warehousing wind turbine towers and general construction. Heavy hex structural bolts are designed to ensure the clamp loads developed in the assembly are distributed over a larger area than a standard hex heads. They also provide a larger wrenching area to resist rounding off of the head.

The Hex Tap Bolts are standard bolts that are fully threaded. They have a wide variety of applications and are versatile for maintenance and repair workers. The term “Tap Bolt” refers to a Hex Head Bolt that is threaded to the head. The added thread guarantees a fit to a variety of grip ranges for any job. Earnest’s line of Hex Tap Bolts is found in Grade 5 and 8 to ensure the proper strength in every application.

When you are looking for nuts that will provide a better wrench ability and prevent slippage, Hex Hi Nuts will get the job done. With a taller hexagonal face (twice as tall as Hex Nuts), it gives more surface to wrench in hard-to-reach socketed situations. These nuts can be found fastening a variety of applications, including suspensions in trucks and construction vehicles.

A hex jam nut is a thin, low-profile nut with a hexagonal (six-sided) shape. It is designed to be used in combination with another standard nut to "jam" the threads and prevent both nuts from loosening under vibration or load. Jam nuts are often used in applications where space is limited, and a thinner nut is needed.

Hex Large Flange Nuts (No Serrations) are specialized hex nuts that feature a large, flat, circular base (flange) on one side, but without the serrations typically found on other flange nuts. This design provides a greater surface area for distributing pressure and securing materials, without the additional locking function that serrations provide.

A hex machine screw nut is a type of hexagonal (six-sided) nut specifically designed to be used with machine screws. Machine screws are small-diameter screws with fine threading, typically used for precision fastening in light to medium-duty applications. The hex machine screw nut has internal threads that match the threads on a machine screw, allowing the two to be fastened securely together.

Hex Nuts are the most common nuts on the market. For metric sizes, the two most common dimensional standards that metric hex nuts are made to are either DIN 934 or ISO 4032. These two standards will have different tolerances on the thickness and the width across the flats (especially for the M10, M12 and M14 sizes). Functionally these nuts are interchangeable when the same property class is used. Earnest offers hex nuts made to DIN 934 in metric Classes 8 and 10.

Hex Nuts are the most common nuts on the market. Metric hex nuts made to ISO 4032 and DIN 970 have the same tolerance range on the width across flats (wrench size) and thickness. For metric nuts, the two most common dimensional standard referenced are per ISO 4032/DIN 970 or DIN 934. These two standards will have different tolerances on the thickness and the width across the flats (especially for the M10, M12 and M14 sizes). Functionally these nuts are interchangeable when the same property class is used. Earnest offers hex nuts made to ISO 4032/DIN 970 in metric Classes 8 and 10.

A hex serrated flange nut is a specialized type of hex nut that has an integrated flange at the base, with serrations on the flange surface. The flange acts like a built-in washer to spread the load over a larger area, while the serrations provide a locking mechanism that prevents loosening under vibration.

A Hex Serrated Flange Locking Machine Screw is a specialized type of fastener designed for mechanical applications where a secure, vibration-resistant connection is needed. It combines a hexagonal head for easy installation, a built-in flange for load distribution, and serrations underneath the flange that act as a locking mechanism.

A Hex Serrated Flange Locking Machine Screw (Stainless) is a specialized fastener designed to provide a secure, vibration-resistant connection, commonly made from stainless steel for enhanced corrosion resistance. This type of screw combines a hexagonal head, a serrated flange, and machine screw threads, making it ideal for use in various mechanical, automotive, and industrial applications.

A hex serrated flange nut is a specialized type of hex nut that has an integrated flange at the base, with serrations on the flange surface. The flange acts like a built-in washer to spread the load over a larger area, while the serrations provide a locking mechanism that prevents loosening under vibration.

The more threads in a nut the better the strength, and Hex Thick Nuts, or Thick Nuts, have just that. Taller than Hex Nuts, Thick Nuts provide extra threads, increasing their grip strength. Trucks use this extra strength for fastening their suspensions. Earnest carries fine thread Grades 5 and 8.

Otherwise known as Lug Nuts, Wheel Nuts are specifically designed to hold tire rims to an axle. These nuts are primarily used in automotive and construction equipment. In order to match the rim, the nuts are engineered to 60 degree, 90 degree, and radius faces.

A chemical treatment applied to zinc or cadmium-plated fasteners to improve corrosion resistance. This finish forms a protective layer that helps prevent white rust and slows corrosion near small scratches or around areas of minor damage. Hexavalent chromate coatings are effective but have environmental and health concerns, which is why alternatives like trivalent chromate are becoming more common.

Hook Bolts, J-Bolts, or Bent Bolts have two designs used in rock quarries and mines. The J-Bolt Special Bend, otherwise known as Hook Bolt or Shaker Screen Bolt, supports angled ironed shaker screen frames. Resembling a checkmark, the bolt is heat treated to a Rockwell hardness of 25/34 to improve resistance to bending. The other design, the J-Bolt Round Bend, has a rounded radius hook to support tubular shaker screen frames. These bolts shift through dirt and heavy rock — a true testament to their strength.

Hot Dip Galvanized is a corrosion-resistant finish created by immersing a steel fastener into a bath of molten zinc. This process forms a thick, durable zinc coating that bonds to the steel surface, providing long-term protection, especially in outdoor or harsh environments.

Appearance - Fasteners with a Hot Dip Galvanized finish have a dull gray or matte silver appearance with a rough or uneven texture. The finish is noticeably thicker than other zinc coatings and may affect thread fit.

A manufacturing process that shapes metal into fasteners at elevated temperatures, specifically above the material's recrystallization point. Heating the metal makes it significantly more ductile and easier to form, requiring less force than cold forming. Hot forming is typically for larger-diameter fasteners, complex shapes, or materials that are difficult to work with at room temperature. Parts produced through this method may require an additional heat treatment to achieve the desired strength level.

A Huck bolt is a type of permanent, high-strength, vibration-resistant fastener used in heavy-duty applications where traditional bolts or rivets may loosen over time. Huck bolts are part of a category known as lockbolts, and they are widely used in industries such as railroad, aerospace, construction, and heavy equipment manufacturing.

A critical phenomenon where certain metals, especially high-strength steels used in fasteners, lose their ductility and become brittle due to the absorption of atomic hydrogen. This hydrogen can be introduced during manufacturing processes such as electroplating or acid pickling, or from environmental exposure like corrosion. The absorbed hydrogen migrates within the material, accumulating at stress points and internal defects. Under sustained or residual stress, this leads to the sudden, often delayed, and frequently catastrophic fracture of the fastener, even at loads well below its design strength. Post-plating baking is a common mitigation strategy to reduce this risk.