Types Of Screws

There are many types of screws, from lag screws to self-tapping sheet rock screws, so we’ve put together this guide to help you choose the best screw for your project or identify which screws you have on hand. 

This guide covers the most common types of screws and their uses before diving into which screws work best for different types of projects. Here’s everything you need to know.

• What Are The Different Types Of Screws?
• Lag Screws
• Set Screws
• Socket Screws
• Flange Screws
• Hex Cap Screws
• Machine Screws
• Wood Screws
• Floorboard Screws
• Self-Tapping Sheet Metal Screws
• Specialty Screws
• How To Choose The Right Screw Type For Your Project
• Screw Drive Styles
• Screw Point/Thread Styles
• Screw Head Styles
• Screw Type FAQs
• Browse Heavy-Duty, High-Quality Screws From The Fastener Depot

What Are The Different Types Of Screws?

Each screw type offers unique features and strengths. Understanding these variations is the key to ensuring your project’s structural integrity and success. Here's a breakdown to help you understand the different types of screws and their uses:

Lag-Screws

Lag screws, often referred to as lag bolts, are heavy-duty fasteners known for their large diameter and distinctive hexagonal head. Lag screws are typically constructed from high-strength materials such as stainless steel or zinc-coated steel, offering excellent corrosion resistance and durability. Their coarse threads feature a deep pitch, designed to provide a secure grip, making lag screws indispensable for projects that require a strong hold.

When to Use Lag Screws

Lag screws are a preferred choice for projects that demand secure and long-lasting connections. Some common lag screw uses include:

• Deck Construction: Ideal for fastening wooden beams and posts, lag screws provide the structural strength necessary for supporting deck frameworks.

• Timber Framing: Perfect for joining large pieces of timber, lag screws ensure stability and mitigate movement.

• Building Retaining Walls: Their robust load-bearing capability suits them well for constructing retaining walls or similar outdoor structures.

• Heavy Furniture Assembly: Use lag screws to assemble bulky wooden furniture for a solid and reliable build.

• Anchoring Structures to Masonry or Concrete: When combined with suitable anchors, lag screws can effectively secure frameworks or heavy items to concrete or masonry.

Set Screws

Set screws are unique fasteners that are headless and feature a recessed drive, often utilizing hex (Allen) or slotted drives. Typically constructed from durable materials like carbon or stainless steel, set screws ensure a reliable and discrete fastening solution. Their design allows them to sit flush within the surface, providing an unobtrusive connection without the need for a protruding head.

When to Use Set Screws

Set screws are commonly used in applications where securing an object within or against another is required, without the need for additional nuts. Set screws are used for:

• Machinery and Equipment: Set screws are frequently used to fasten components such as gears, pulleys, or collars to shafts, ensuring they remain securely in position during operation.

• Furniture Assembly: Providing an invisible fastening solution, set screws are perfect for joining parts of furniture where aesthetics are important.

• Precision Instruments: They are essential in delicate devices and instruments where a small, precise fastening is necessary.

• Electrical Components: Set screws can secure components within electrical assemblies, providing a stable and reliable connection.

Socket Screws

Socket screws are characterized by their cylindrical heads and an internal hex drive, which require a hex key (Allen wrench) for installation. Socket screws are commonly made from high-strength materials such as alloy steel, providing excellent tensile strength and durability for demanding applications.

When to Use Socket Screws

Socket screws are ideal for applications where a strong, high-torque connection is necessary, and where minimal protrusion is required. Common uses include:

• Mechanical Assemblies: Socket screws provide sturdy fastening in machinery, where securing and aligning components with precision is essential.

• Automotive Applications: Frequently used in engine assemblies and other automotive components demanding high-stress tolerance.

• Tool and Die Making: They are a popular choice in the assembly of tooling components due to their strength and compact head design.

• Electronics Enclosures: Socket screws are perfect for fastening parts within electronic enclosures, offering a sleek, low-profile finish.

Flange-Screws

Flange screws feature a distinctive design with a built-in flange just under the head, which distributes pressure evenly across the fastened surface. This eliminates the need for a separate washer and provides a more secure fastening. They are often made from materials like stainless steel or alloy steel for strength and corrosion resistance.

When to Use Flange Screws

Flange screws are particularly useful in situations where an even load distribution is required, making them suitable for a variety of applications, such as:

• Automotive Manufacturing: Widely used in automotive assembly due to their ability to provide secure and even clamping force on components.

• Steel Constructions: Ideal for use in metal frameworks and structures where reliability and stability are critical.

• Machinery and Equipment: Flange screws help in securing lids and covers, offering both tight fastening and ease of access for maintenance.

• Electrical and Electronic Assemblies: Used for mounting components onto metal surfaces while ensuring low electrical resistance through even load distribution.

Hex Cap Screws

Hex cap screws, distinguished by their hexagonal heads, are designed for use with a wrench or a socket. They feature either fine or coarse threads and are typically manufactured from durable materials such as stainless steel, zinc-plated steel, or alloy steel, making them suitable for various high-strength applications.

When to Use Hex Cap Screws

Hex cap screws are versatile fasteners ideal for applications requiring secure, heavy-duty connections. Common uses include:

• Construction Projects: Frequently used in building frameworks and structures, providing robust connections between wooden or metal components.

• Automotive Repairs and Manufacturing: Essential for engine and body assemblies where reliability under stress is paramount.

• Machinery Assembly: Ideal for mounting and securing pieces of machinery, where high tensile strength and precision are required.

• Bridge and Highway Construction: Used in large-scale infrastructure projects due to their strength and reliability in structural connections.

Machine Screws

Machine screws are small fasteners with a uniform diameter, designed to be threaded into a tapped hole or used with nuts. They come in a variety of head shapes and are generally made from materials like stainless steel, brass, or zinc-plated steel for corrosion resistance and strength.

When to Use Machine Screws

Machine screws are ideal for precision-oriented applications and are commonly used in the following:

• Electronics Assembly: Used to fasten electronic components securely within devices, such as computers and appliances.

• Small Machinery: Perfect for assembling and maintaining small machines where precision and tight fastening are crucial.

• Panel Mounting: Used in attaching panels and covers in enclosures, offering a neat and secure fastening solution.

• Appliance Repair: Commonly found in household appliances, machine screws provide reliable connections for repairs and assembly.

Wood Screws

Wood screws, including deck screws, are specifically designed for fastening wood. They feature a sharp, tapered point and deep, coarse threads to ensure a strong grip in wood materials. Typically made from corrosion-resistant materials like stainless steel or coated steel.

When to Use Wood Screws

Wood and deck screws are essential for projects involving wood materials and are used in:

• Deck Building: Ideal for securing decking boards to the frame, providing durable and weather-resistant connections.

• Furniture Assembly: Commonly used in constructing wooden furniture, ensuring a strong and reliable hold.

• Carpentry Projects: Used for various woodworking tasks, from cabinetry to framing.

• Outdoor Structures: Such as pergolas and fences, where corrosion resistance is important due to exposure to the elements.

Floorboard Screws

Floorboard screws are designed with a thread-cutting tip and a wide head to secure floorboards tightly while reducing the chance of splitting the wood. They often come with a self-countersinking head for a flush finish.

When to Use Floorboard Screws

Floorboard screws are specialized for flooring applications, including:

• Hardwood Floor Installation: Providing a secure and aesthetic fastening for hardwood boards.

• Subflooring Assembly: Used in attaching subflooring to joists, ensuring a squeak-free, stable floor surface.

• Tongue and Groove Flooring: Excellent for securing tongue and groove floorboards without damaging the joints.

• Renovation Work: Ideal for replacing or reinforcing loose boards, offering long-lasting repairs.

Self Tapping Sheet Metal Screws

Self-tapping sheet metal screws, known for their drill bit point, are designed to drill their own pilot holes as they are driven into metal or other surfaces, simplifying installation and reducing processing time.

When to Use Self-Tapping Sheet Metal Screws

Self-tapping screws are perfect for applications where speed and efficiency are essential, such as:

• Sheet Metal Construction: Used extensively in fastening sheet metal in HVAC, roofing, and siding.

• Metal Framing: Ideal for creating frames and supports in metal constructions without pre-drilling.

• Automotive and Trailer Fabrication: Providing secure fastening for metal parts and panels.

• Metal Stud Wall Construction: Used for assembling metal stud walls quickly and efficiently.

Specialty Screws

Specialty screws encompass a wide variety of unique designs tailored for specific applications, including security screws, mirror screws, and others with unique head shapes or driving mechanisms.

When to Use Specialty Screws

Specialty screws cater to niche requirements and unique environments, such as:

• Security Applications: Security screws with tamper-proof heads are used in public or high-risk areas to prevent unauthorized disassembly.

• Decorative Installations: Mirror screws and similar types provide aesthetic fastening solutions in furniture and decor.

• High-Temperature Environments: Certain specialty screws are designed to perform under extreme temperatures without losing integrity.

• Specific Industrial Uses: Utilized in applications requiring resistance to vibration, chemicals, or other specific conditions.

How To Choose The Right Screw Type For Your Project

When choosing the right screw for your project, it's essential to consider not just the type of screw but also its drive style, point/thread style, and head style. These characteristics play a critical role in determining the functionality, convenience, and effectiveness of the screw in specific applications. Here’s a look at screw drive types, point/thread styles, and heads. 

Screw Drive Styles

Screw drive style refers to the type of tool (driver) required to install the screw, which can significantly impact ease of use and the force applied during fastening. 

Common drive styles include Phillips, flat/slotted, and hex or Allen, among others. Selecting the appropriate drive style ensures you have the right tools on hand and can provide better torque control and reduced cam-out, increasing efficiency and minimizing the risk of damage during installation.

Screw Point/Thread Styles

The point and thread styles of a screw determine how it penetrates materials and how strongly it holds. For example, coarse threads are ideal for wood as they provide a better grip, while fine threads are suitable for metal applications requiring precision. Self-drilling points can eliminate the need for pre-drilled holes, saving time and reducing effort in certain tasks. 

Screw Head Styles

Different head styles, such as flat, pan, or round, affect both the appearance and function of the screw once installed. Flat heads allow screws to sit flush with or below the surface, providing a smooth finish ideal for cabinetry or wood flooring. In contrast, round heads may be more appropriate where aesthetic is less crucial, but additional holding power is needed.

Screw Type FAQs

What Screws To Use for Wood?

Generally, screws made of steel are idea for woodworking projects, such as building shelves, furniture, decks, fencing, and more. Steel wood screws are designed with a tapered shaft, sharp point, and coarse threads that grip the wood tightly. Although self-tapping screws can also be used for certain wood applications, they are best suited for instances where quick, easy fastening of thin wood pieces is needed.

What Screws To Use for Metal?

Metal screws, including steel machine screws and steel self-tapping screws, are perfect for tasks involving metal applications. Machine screws are typically used with nuts or tapped holes in metal, securing components in machinery or electronics. Self-drilling screws, equipped with a drill point, eliminate the need for pre-drilled holes, making them ideal choices for attaching sheet metal in roofing and HVAC.

What Screws To Use for Plastic?

When working with plastic, screws that prevent cracking and ensure a tight fit are necessary. Plastic screws are often designed with sharp, intricate threads for smoother penetration and holding. They are commonly used in assembly lines, furniture, and electronics, ensuring components are securely fastened without damaging the material.

When To Use Self-Tapping Screws?

Self-tapping screws are versatile fasteners capable of creating their own threads as they are driven into material, which is beneficial for materials like metal and hard plastics. These screws are ideal for applications where pre-drilled holes are not feasible. Self-tapping screws are typically used in HVAC ductwork and assembling metal frames. 

When To Use Masonry Screws?

Masonry screws, such as sidewalk bolts and washered wing nuts, are specialized for concrete, brick, and other masonry materials. Sidewalk screws are designed with aggressive threads that provide a strong hold in brittle surfaces. They are essential for installing hurricane shutter hardware and securing structures to sidewalks and other masonry surfaces, ensuring stability and safety in extreme conditions.

Browse Heavy Duty, High-Quality Screws From The Fastener Depot

We hope our guide on the various types of screws helps you make an informed decision regarding the best screws for your project. At The Fastener Depot, a family-run business, we are dedicated to offering both top-quality screws and the guidance you need to choose the perfect fasteners for your projects.

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