8 by 1/2 truss head screws

Product Description

The #8 x 1/2″ truss head screw is a versatile fastener. It is designed for a wide range of light to medium-duty applications across sheet metal, wood, plastic, and composite materials.

This screw features a low-profile truss head. It provides a larger bearing surface than a standard pan head, helping to prevent pull-through while maintaining a clean, finished appearance.

With a #8 thread diameter and a 1/2-inch overall length, this screw is ideal for fastening thinner materials. A longer fastener would be unnecessary or cause damage.

Available in multiple drive types and point configurations, the #8 x 1/2″ truss head screw adapts to virtually any application in construction, HVAC, automotive, and general maintenance.

8 by 1/2 truss head screws

What Are the Different Point Types for #8 x 1/2″ Truss Head Screws?

A common question is which point style is correct for a specific material.

Self-Drilling (TEK) Point:
This features an engineered drill point and flutes that remove material efficiently. It properly sizes the hole for threads in one step. It is ideal for fastening 20 to 12-gauge metal in metal-to-metal applications without pre-drilling.

Type A Tapping Point:
This is a thread-forming tapping screw with wider spaced threads and a gimlet point. It is designed for self-starting in thin metal or resin-filled plywood. These screws create their own mating threads as they are driven.

Type 17 Thread Cutting Point:
This features a Type-17 point with coarse threads for fastening materials to wood or wood-substitute materials. Predrilling is recommended depending on the substrate.

Plastite-Style Thread-Forming Point:
This is a trilobular thread-rolling screw with extra wide spacing. It is specifically designed for thermoplastics and engineering resins. This point increases holding strength while reducing material displacement.

What Materials and Finishes Are Available for #8 x 1/2″ Truss Head Screws?

The screw is manufactured from various materials to suit different environmental conditions.

18-8 Stainless Steel:
This offers general atmospheric corrosion resistance. It is RoHS compliant. It is best for indoor and outdoor applications where rust resistance is needed.

305 Stainless Steel:
This is high-quality stainless with excellent corrosion resistance. It features a Type-17 point for wood applications. It is best for wood and wood-substitute materials in exterior or moist environments.

8 by 1/2 truss head screws

Carbon Steel with Zinc Plating:
This is cost-effective with good corrosion resistance for interior use. It has an electrogalvanized surface. It is best for general construction, HVAC, sheet metal work, and body work.

What Drive Types Are Available for #8 x 1/2″ Truss Head Screws?

The screw is available with several drive styles.

Phillips Drive:
This is the most common drive type. It is compatible with standard #2 Phillips bits. The recess is designed to cam-out before being overdriven, preventing damage to the workpiece.

Square Socket (Loxxon) Drive:
This features a square hollow drive that provides excellent bit engagement and reduces cam-out. It is ideal for high-torque applications where consistent driving is required.

Slotted Drive:
This is a traditional drive style. It is suitable for applications where slotted drives are specified or preferred.

How Do You Install #8 x 1/2″ Truss Head Screws?

Installation method depends on the point type.

For self-drilling screws, simply position the screw against the material and drive with a #2 Phillips bit or appropriate driver. The engineered drill point eliminates the need for pre-drilling, saving significant installation time.

For Type A tapping screws, the sharp gimlet point helps start the screw. The threads form their own path as the screw is driven.

For Type 17 wood screws, predrilling is recommended depending on the substrate to prevent splitting.

Always use the correct driver size for your chosen drive type.

What Are the Head Dimensions of a #8 x 1/2″ Truss Head Screw?

The truss head is distinguished by its low-profile, wide-diameter design.

For a standard screw conforming to ASME B18.6.3 specifications, the head diameter ranges from 0.285 inches to 0.312 inches. Head height is 0.103 to 0.118 inches.

Some models feature an oversized head with a diameter of 0.374 inches. This provides an even larger bearing surface for applications requiring maximum pull-through resistance.

This wide head design distributes clamping force over a larger area. This makes it excellent for fastening softer materials or applications where a clean finish is desired.

What Is the Difference Between Self-Drilling and Self-Tapping Screws?

This is a frequently asked distinction.

Self-drilling screws feature a drill bit-style point that actually drills the pilot hole as the screw is driven. They are designed for metal-to-metal fastening and do not require a pre-drilled hole.

Self-tapping screws have a pointed tip but rely on a pre-drilled pilot hole or the material’s inherent softness to create threads. Type A tapping screws are self-starting but do not drill their own hole.

Choose self-drilling for speed and convenience in metal applications. Choose self-tapping for thin materials or when you already have pilot holes.

What Are the Typical Applications for #8 x 1/2″ Truss Head Screws?

The screw is suitable for numerous applications.

For HVAC and sheet metal work, it fastens ductwork, metal studs, and sheet metal components. Self-drilling TEK screws are particularly popular for these applications.

For stucco and plaster, it securely fastens 20 to 12-gauge metal without pre-drilling. For body work, moldings, and trim, Type A tapping screws are designed specifically for automotive body work.

For plastic assembly, thread-forming screws with trilobular design are ideal for thermoplastics, reducing the need for inserts. For woodworking, Type 17 point screws fasten materials to wood or wood-substitute materials.

For general maintenance and repair, the 1/2-inch length is perfect for fastening thin materials where longer screws would protrude or cause damage.

What Should You Consider When Choosing a #8 x 1/2″ Truss Head Screw?

When selecting your screw, consider several factors.

First, consider the base material. Metal applications typically call for self-drilling or Type A tapping screws. Wood applications require Type 17 screws. Plastic applications benefit from trilobular thread-forming screws.

Second, consider the corrosion environment. For outdoor or high-moisture applications, choose stainless steel. For interior, dry applications, zinc-plated carbon steel is sufficient and more economical.

Third, consider installation volume. For large projects, consider bulk packaging. Screws are available in quantities ranging from 50-piece packs to 10,000-count boxes.

Finally, consider drive compatibility. Ensure you have the correct driver bits for your chosen drive style.