13 Types of Screws for Metal, Plastic, and More

Screws are one of the most common types of fasteners used in product assembly and construction projects. They are available in a wide range of shapes, sizes, materials, and drive types to suit different applications. Knowing the main categories and applications of screws allows you to select the best option for your specific needs.

Introduction to Screws

Screws are externally threaded fasteners that form a bond by digging into a material when turned, rather than friction like nails. The spiral ridges or threads grip the surface of the materials being joined and hold them tightly together.

Compared to nails, screws form a stronger connection, can be removed and reused, and can be used with a wider range of materials. The turning action of screws also reduces wood splitting that can occur with hammering.

Screws come in many different head shapes, drive types (slot, Phillips, Torx, etc), diameters, lengths, thread patterns, and materials such as steel, stainless steel, brass, nylon, and titanium. Understanding these variations helps ensure you choose the optimal screw for the application.

Parts of a Screw

The key components of a screw include:

  • Head – Flat top with a shape that determines the drive type. Hex, slotted, Phillips, Torx heads are common.
  • Drive – Recessed area that allows screwdrivers or drill bits to engage and turn the screw.
  • Shank – Smooth cylindrical body below head. May be partially or fully threaded.
  • Threads – Spiral ridges that dig into materials as the screw is turned. Vary by pitch, diameter, shape.
  • Tip – Tapered end that first contacts the material being fastened. May be pointed, blunt, or flat.

Advantages of Screws

Screws have several benefits that make them a versatile and effective fastener:

  • Strong holding force from threads digging into material.
  • Reusable since they can be removed and re-driven.
  • Wide material suitability, from wood to plastic to metal.
  • Resist vibration loosening better than nails.
  • Enable angled joining of materials.
  • Variety of head drives for different applications.
  • Adjustable grip by increasing or decreasing turns.

13 Common Types of Screws

There are many different classifications of screws defined by their drive, head shape, thread pattern, material, and applications. Here are 13 of the most common types:

1. Slotted/Flat Head Screws

Description: Feature a flat top with a single slot for a flathead screwdriver. The flat head sits flush against the material.

Use Cases: General purpose fastening for wood, plastic, and thin metal where head appearance is not important. Most common where cost is critical.

2. Phillips Head Screws

Description: Have a cross-shaped recess drive for Phillips screwdrivers. Tapered underhead forces material outward for increased holding power.

Use Cases: Very common for fastening wood, plastic, and sheet metal. Taper provides excellent grip and centers screwdriver.

3. Pozidriv Screws

Description: Like Phillips but with additional 4 contact points for greater torque. Not to be confused with Phillips.

Use Cases: Common in European furniture assembly. Requires specific Pozidriv screwdriver for best grip.

4. Torx/Star Screws

Description: Star-shaped recess drive provides excellent torque transfer for high tightening force.

Use Cases: Automotive and aerospace assembly, security screws, electronics. Requires specific Torx driver for grip.

5. Hex Head Screws

Description: Hexagonal recess drive distributes force equally for increased resistance to stripping.

Use Cases: Most common screw for metals, machinery assembly, construction. Allows high tightening with hex wrenches.

6. Socket Head Cap Screws

Description: Fully threaded with a low profile hex socket drive recessed into a cylindrical head.

Use Cases: Precision machined fasteners for industrial applications. Permanent assembly of metal parts.

7. Pan Head Screws

Description: Broad domed head with Phillips or slotted drive. Head provides large contact area.

Use Cases: Electronics equipment, appliance assembly. Provides greater holding power and spreads force.

8. Round Head Screws

Description: Cylindrical domed head with slotted drive. Head curved over shank.

Use Cases: Metal fabrication, assembling sheet metal, attaching hinges, fastening metal framework.

9. Oval Head Screws

Description: Oval shaped head with slotted or Phillips recess. Smoother curves than round head.

Use Cases: Furniture assembly, cabinetry, attaching door hinges. Provides clean appearance.

10. Truss Head Screws

Description: Low profile dome head with bearing surface that holds flush to material. Phillips drive.

Use Cases: Ideal for thinner metals and wood. Premises wiring, metal roofing, HVAC ducts.

11. Button Head Screws

Description: Cylindrical head rounded at top with Torx or hex socket drive.

Use Cases: Equipment assembly, computer components. Allows flush driving without marring surface.

12. Lag Screws

Description: Fully threaded and heavy duty for fastening into wood. May have hex or square drive head.

Use Cases: Structural connections in timber construction. Larger sizes used to anchor heavy objects.

13. Self-Tapping Screws

Description: Sharpened threads cut into plastic or sheet metal as screw is driven. Varying head drives.

Use Cases: Fastening plastic casings, HVAC ducting, flashing. Form own threads without separate tapping.

Screw Sizes

Some key measurements that define screw size include:

  • Diameter – Thickness of the unthreaded shank given in mm or inches.
  • Thread Count – Number of threads per inch or mm of shank. More threads provide greater holding power.
  • Length – Overall length from tip to head end. Given in mm or inches.
  • Gauge – Screw diameter decreases as gauge number increases. Smaller gauge = larger diameter.
  • Head Size – Diameter of the screw head. Matched to recess size.

Make sure to select screws of the proper thread pattern, size, head configuration, and material for your specific application. Using the wrong size or type can lead to screw breakage or damage to the surrounding material.

Screw Drive Types

There are many different screw head shapes and corresponding driver types. Common drives include:

Slotted – Single slot for flathead screwdrivers.

Phillips – Cross shape for Phillips screwdrivers. Self-centering.

Pozidriv – Advanced 4-point Phillips alternative. Prevents cam out.

Torx – Star shape with high torque capability. Common in electronics.

Hex – Hexagonal socket for hex wrenches or Allen keys. Distributes torque evenly.

Square – Square recess accepts square drive tools. Often in electrical applications.

** Robertson** – Square socket with tapered sides. Common in Canada.

Tri-Wing – Proprietary triangular recess used for electronics and appliances.

Spanner – Double-pin recess requires special spanner screwdriver. Used for tamperproof applications.

Clutch – Rounded indentations transmit higher torque. Used in automotive and appliances.

Bristo – Concave round shape. Provides low cam out for precision applications.

Mortal – Semi-circular indentations angled outward. Used for high tension applications.

Torq-Set – Rounded pyramid shape optimized for power tools. Reduces cam out in high torque uses.

Make sure to always use the properly matched driver for your screw head to avoid stripping or damage.

Screw Thread Patterns

The ridges or threads that run around the screw shank come in standardized patterns defined by spacing and shape:

  • Unified – Most common screw thread in the US. Used for general purposes.
  • ISO Metric – International standard with thread pitch defined in mm. Very prevalent.
  • Whitworth – Standardized thread pattern used primarily in Britain and Europe.
  • Buttress – Angled asymmetric thread optimized for applications with axial loading along the screw.
  • Worm Screw – Sharply angled V-shaped thread provides large holding power and friction.
  • Square Thread – Square profile rather than angular wedge shape. Prevents vibrational loosening.
  • Acme Thread – Trapezoidal thread optimized for smooth linear motion when paired with a nut.

Make sure to match the screw thread pattern with the internal threads of the receiving hole or nut. Mismatching can cause cross-threading and damage.

Material Composition

Screws used for manufacturing and construction come in a variety of materials:

  • Carbon steel – Simple steel screws with moderate strength. The most common and cost-effective option.
  • Stainless steel – Improved corrosion resistance and appearance where desired. More expensive.
  • Alloy steel – Heat treated for increased strength. Used in high stress applications.
  • Brass – Decorative option that offers low magnetic properties. Used with conductive metals.
  • Bronze – Attractive finish and good corrosion resistance. Ideal for harsh outdoor environments.
  • Nylon – Lightweight non-conductive screws suitable for electronics and plastics.
  • Titanium – Extremely strong but lightweight screws. Used in high-tech aerospace applications.

Make sure to select screws in an appropriate material for your environmental conditions, strength needs, and compatibility with the underlying materials being joined.

Common Screw Applications

Screws are used in thousands of applications thanks to their versatility. Here are some of the most common uses:

  • Wood construction – Joining wood framework, attaching deck boards, assembling furniture
  • Metal fabrication – Fastening brackets, machinery, frames, electrical boxes
  • HVAC systems – Assembling ductwork, attaching grilles and registers
  • Appliance assembly – Securing internal components, fastening plastic casings
  • Electronics equipment – Mounting circuit boards, fastening computer components
  • Automotive/aircraft – Critical fasteners in engine and body components
  • Construction – Securing drywall, decking, roofing, structural joints
  • Medical devices – Precision internal components, prosthetics, implants
  • Plumbing – Assembling PVC piping and fittings

Make sure to use properly sized and headed screws suited for the materials being worked with. Pilot holes are often needed for wood and sheet metal to prevent splitting. Washers can also help distribute load.

Tips for Choosing the Right Screw

Keep these key factors in mind when selecting screws for a job:

  • Material – Match metal composition to expected corrosion, strength and appearance needs.
  • Size – Consider diameter, length, thread count required. Too small risks stripping. Too large can split material.
  • Head Type – Low profile, tapered, flat heads for different flushness and grip needs.
  • Drive – Choose drive that fits your tools and allows adequate torque.
  • Thread Pattern – Match to receiving hole/nut threading. Mismatched threads won’t engage properly.
  • Shear/Tensile Strength – Assess required load capacity and securement performance.
  • Environment – Indoor/outdoor use, temperature extremes, exposure to elements/chemicals.
  • Code Compliance – Meet any regulatory fastener standards for critical structural connections.

Take the time to carefully evaluate your application and select optimal screws. Consulting manufacturers’ technical guidances can also help narrow suitable options.

Frequently Asked Questions About Screws

What are the most popular screws for fastening wood?

For most general woodworking applications, Phillips or Pozidriv flat head or oval head wood screws are very common. Slotted varieties are also widely used due to their simplicity and cost-effectiveness.

How do I remove a stripped screw?

Use a screw extractor bit that bites into the screw head, allowing you to back the screw out. Place rubber bands or tape between the extractor and screw to improve grip. Impact drivers can also help provide extra turning torque.

What’s the difference between coarse and fine thread screws?

Coarse threads are further apart and deeper, allowing for faster insertion and use in softer materials like wood. Fine threads have more closely spaced shallower ridges for gripping hard materials like metal more effectively.

How do I determine the proper screw length for an application?

Consider the combined thickness of all materials being joined and add approximately 1/2 to 3/4 inch extra length to ensure adequate fastening grip. Avoid excess length that risks poking through the bottom.

Which screw head is flush with the surface?

Countersunk screws with tapered undersides sit flush with the material surface. Button head and pan head screws also provide relatively smooth low profiles.

How do I stop screws from vibrating loose over time?

Use self-locking screws with nylon or nylok inserts that grip the threads. Loctite threadlockers adhesive can also be applied to secure screws.

What pilot hole size should I drill for screwing into hardwood?

For soft woods like pine, drill pilot holes around 70% of the screw shank diameter. For hardwoods like oak, pilot holes closer to 90% diameter are recommended prevent splitting.

Can I reuse screws that have been removed?

Most times yes, provided the threads are in good condition and the screw tightened smoothly when removed. Inspect for any damage like cracks that could compromise reused screws.

Why choose Torx over Phillips head screws?

Torx drivers allow for greater torque transfer and reduced risk of cam out stripped screws. The star shape improves grip, especially for high tightening force applications.

How much torque should be applied to tighten screws?

Follow manufacturer recommended torque specs if provided. Use the lowest torque needed to tighten screws snugly without stripping them. Larger screws and those securing critical components need higher torque.

Key Takeaways on Screw Types and Applications

  • Screws are threaded fasteners available in a vast range of shapes, drives, sizes, materials, and specifications.
  • Choosing the optimal screw requires matching attributes like head type, material, length, drive type, and diameter to your application.
  • Slotted, Phillips, Torx, Hex, and other drives each offer particular advantages and tool compatibility.
  • Wood screws effectively fasten lumber, furniture, decks, while sheet metal screws are ideal for steel and HVAC work.
  • Understanding screw size numbering conventions, measurements, strength properties helps selection.
  • Take care to properly match thread patterns between screws and receiving holes or nuts.
  • Pilot holes, proper torque, fitment with washers, and anti-vibration methods help create secure screw joints.


With such a wide variety of screw types and designs available, it is important to carefully consider the characteristics of your application to select optimal screws. Understanding the differences in drives, heads, threads, materials, sizes, strengths, and intended uses will ensure you choose the right screws for the job.

Take the time to evaluate factors like the materials being joined, environmental conditions, appearance needs, assembly alignment, required load capacity, and access to tools. Consulting technical specifications and manufacturer guidance can also help you choose suitable screws.

With the proper knowledge and research, you can be confident selecting screws that perform well, create lasting bonds, install efficiently, resist corrosion and fatigue, and deliver the ideal fastening solution.