The T8X8 (8-1/2-A-TR-PH-SS) is an aviation-grade #8 truss-head self-tapping sheet metal screw made from stainless steel. It is commonly used for fastening thin sheet metal, interior panels, brackets, and non-structural aircraft components where a wide bearing surface and vibration resistance are required.

The truss head design provides a larger contact area than standard pan heads, helping to distribute load and reduce pull-through in thin materials. The Type A self-tapping thread allows the screw to form its own mating thread in softer metals or pre-drilled holes without requiring a nut.

Key features include:

#8 diameter sheet metal screw (imperial)
Length: 1/2 inch (typical T8X8 spec)
Truss head (wide, low-profile bearing surface)
Phillips drive
Type A self-tapping thread (for sheet metal / thin aluminum)
Stainless steel construction (corrosion resistant)
Used in aircraft interior and airframe non-structural assemblies
Suitable for vibration-prone environments with thin material stack-ups
Common replacement fastener in general aviation maintenance