Flat Head Screw Dimensions: Understanding 82-Degree Specifications

82-degree flat-head screws are available in a variety of types, including machine screws, cap screws, and self-locking machine screws. They can be purchased from companies such as Mil-Spec Fasteners Corp. and Apex Fasteners, and come in both standard and custom sizes. The degree of a flat-head screw refers to the angle of the countersink, with 82-degree countersinks believed to have been introduced by Morse and subsequently becoming the ASME standard.

Flat Head Cap Screws: 82-degree angle vs. 90-degree angle

Flat head cap screws are available in different angular configurations, with 82-degree and 90-degree angles being the most commonly discussed. The angle of a flat head cap screw refers to the angle of the screw head's underside, which is the conical portion that sits inside a countersunk hole. The choice between an 82-degree and a 90-degree angle for flat head cap screws depends on various factors, including the application, material thickness, and industry standards.

82-Degree Flat Head Cap Screws

Flat head cap screws with an 82-degree angle are typically used for inch-based measurements and are common in English flat head socket cap screws. This angle is specified in the ASME B18.3 standard for flat head socket cap screws. The 82-degree angle may have been chosen as a balance between the thickness of the material and the strength of the fastener. It is believed that this angle allows for a tighter fit, especially when used with common 82-degree countersink bits, as the holes are usually in metal, which does not compress like wood.

90-Degree Flat Head Cap Screws

Flat head cap screws with a 90-degree angle are typically associated with metric measurements. These screws are commonly found in hardware stores and are used in various applications, including wood screws. From a manufacturing standpoint, a 90-degree angle may be preferred as it simplifies the production process. Additionally, the 90-degree angle is specified in the ISO 2009:1994 standard for slotted countersunk flat head screws with metric measurements.

Other Angles

It is worth noting that flat head cap screws are also available in other angles, such as 100-degree angles, which are used for thinner materials. The choice of angle ultimately depends on the specific requirements of the application, the type of material, and industry standards.

In conclusion, the selection of an 82-degree or 90-degree angle for flat head cap screws depends on the measurement system, material thickness, strength requirements, and industry standards. While 82-degree angles are common for English screws and provide a tight fit, 90-degree angles are preferred for metric screws and offer advantages in manufacturing.

82-degree flat head machine screws: slotted vs. Phillips drive

82-degree flat head machine screws are available in both slotted and Phillips drive styles. The drive style, or drive recess, refers to the type of tool needed to install or remove the screw.

Slotted Drive

The slotted drive, also known as a slot drive or flat-blade drive, is a single horizontal indentation in the fastener head. It is driven by a flat-bladed screwdriver and was the first type of screw drive to be developed. The slotted screw is commonly found in existing products and installations, as well as in simple carpentry work and applications where minimal torque is needed. It is also used in the restoration of antique furniture, vehicles, and equipment.

However, the slotted drive is not well-suited for installation by power tools, as the driver often cams out of the slot, causing damage to the screw and surrounding material. For this reason, other drive types have replaced the slotted drive in many applications. To prevent damage, it is important to match the driver size to the screw head.

Phillips Drive

The Phillips drive, also known as the cross-head or cross-point drive, is a cross-shaped indentation in the fastener head. It was designed to address several problems with the slotted drive, including high cam-out potential, the need for precise alignment, and difficulty of driving with powered tools. The Phillips drive allows for increased torque and reduced slippage compared to the slotted drive.

To install or remove a Phillips drive screw, a Phillips screwdriver or bit is required. The size of the Phillips driver should match the size of the screw head to prevent damage. Phillips drive screws are designated by the letters "PH" followed by a size code (0000, 000, 0, 1, 2, 3, or 4) that indicates the order of increasing size.

Both slotted and Phillips drive styles are available for 82-degree flat head machine screws. The choice between the two depends on the specific application and the tools available. The slotted drive is simple and widely used, but it may not be suitable for power tools and high-torque applications. The Phillips drive offers improved performance in these areas but requires a matching driver to avoid damage.

Flat head machine screw dimensions: nominal size or basic screw diameter

The nominal size or basic screw diameter of 82-degree flat-head machine screws varies depending on the specific screw and its intended application. Here is a detailed breakdown of the dimensions and specifications of these screws:

Phillips Flat Head Machine Screw – 82 Degree:

This type of 82-degree flat-head screw features a Phillips head drive, which is characterised by a cross-shaped recess. The dimensions of this screw include the nominal size or basic screw diameter, which determines the overall size of the screw. The specific diameter values for this screw type can be found in size charts and specifications provided by manufacturers.

Slotted Flat Head Machine Screw – 82 Degree:

The 82-degree flat-head machine screw with a slotted drive features a single horizontal indentation on the head. The nominal size or basic screw diameter of this screw type varies depending on the manufacturer and the intended application. It is important to refer to the relevant size charts and specifications to determine the exact diameter measurements.

Flat Head Machine Screw Dimensions:

When considering the dimensions of 82-degree flat-head machine screws, it is important to look beyond just the nominal size or basic screw diameter. These screws have specific dimensions for various features, including the protrusion above the gaging diameter, the recess penetration gaging depth, and the overall head diameter. These dimensions can vary slightly between different screw types and manufacturers.

Applications and Standards:

82-degree flat-head machine screws are commonly used in a variety of applications, including electronics, aviation, and OEM industries. They offer a balance between thickness and the strength of the fastener. It is worth noting that the 82-degree angle for countersinks became the ASME standard, influenced by the earlier "old style" countersunk screws that featured a 76-degree angle.

Flat head cap screw types: self-locking vs. standard

Flat head cap screws are a popular choice for fastening thin materials, such as plates, strips, moldings, and sheet metal. They are designed to provide maximum head contact, flush surfaces, and non-slip wrenching action. The standard 82-degree angle under the head of these screws ensures an accurate and secure fit.

Standard Flat Head Cap Screws

Standard flat head cap screws are ideal for applications where heads cannot protrude and maximum flush and sidewall contact is required. They are commonly used for roller threaders, headers, and overhead rails for chain hoists.

One of the key advantages of standard flat head cap screws is their non-slip driving feature. This ensures that power is transmitted efficiently, without loss through side play, reaming, or slipping. Additionally, the standard screws have accurately formed heads, with clean edges and no burrs, allowing for full leverage during use.

Self-Locking Flat Head Cap Screws

Self-locking flat head cap screws offer a secure and reliable fastening solution. While standard flat head cap screws already provide non-slip driving, self-locking screws take this a step further by incorporating features that prevent loosening or accidental unscrewing.

Self-locking flat head cap screws are commonly used in applications where vibration or movement may cause standard screws to loosen over time. These screws are designed with features such as thread locking, chemical adhesives, or mechanical locking mechanisms to ensure they remain securely in place.

Both standard and self-locking flat head cap screws offer unique advantages. Standard screws provide an efficient and secure fastening solution for thin materials, while self-locking screws add an extra layer of security by incorporating features that prevent loosening. The choice between the two depends on the specific application and the need for added security against loosening.

82-degree flat head screw applications: electronics, aviation, and OEM industries

82-degree flat-head screws are used across a range of industries, including electronics, aviation, and OEM (original equipment manufacturing). Their unique head angle and flat profile make them ideal for specific applications where standard screws may not be suitable.

Electronics

In the electronics industry, 82-degree flat-head screws are often used for securing components and assemblies within devices. Their low profile allows them to fit into tight spaces without causing interference. The angled head also minimizes the risk of components being damaged by the screw head. These screws are commonly used in computers, smartphones, and other electronic devices where space is limited.

Aviation

The aviation industry utilizes 82-degree flat-head screws for a variety of applications. These screws are often made from stainless steel to prevent corrosion. They are used in aircraft structures, such as sheet metal attachments and interior panels. The flat head allows for a smooth surface finish, reducing drag and ensuring aerodynamic efficiency. The pointed end of some 82-degree flat-head screws makes them ideal for penetrating and securing multiple layers of aircraft materials.

OEM Industries

In OEM industries, 82-degree flat-head screws are used in a diverse range of applications. They are often chosen for their ability to provide a flush finish, especially in products with visible surfaces. This type of screw is commonly used in appliances, automotive parts, and machinery. The low profile of the screw head helps to create a sleek and aesthetically pleasing appearance while still providing secure fastening.

The dimensions and specifications of 82-degree flat-head screws vary depending on the intended application. They are available in different sizes, drive types, and materials to meet the specific requirements of each industry. The angle of the head provides distinct advantages, making them a preferred choice where a standard screw would be inadequate.

Frequently asked questions