SPC Performance 15815 3 Pc Flared Hole Die Set

The SPC Performance 15815 is a 3-piece flared hole die set — commonly known as dimple dies — engineered for professional sheet-metal fabrication. This set includes three dies in 3.0", 3.5", and 4.0" sizes, covering the larger end of the spectrum for building rigid, lightweight panels used in race vehicles, off-road builds, and aircraft-inspired fabrication work.

Flared hole dies work by forming a raised flange around a pre-cut hole in sheet metal, dramatically increasing panel rigidity and stiffness without adding weight. The resulting high strength-to-weight ratio makes this technique a staple in motorsports fabrication, roll cage floors, firewalls, and structural panels where every gram matters.

Key Features:

• Set includes three dies: 3.0", 3.5", and 4.0" flared hole dies (individual part numbers 15870, 15875, 15880)
• Engineered using finite element analysis (FEA) and extensive prototype testing for optimized flare angle, bend radius, and length of run
• Designed to eliminate edge tearing even on high-strength 4130 chromoly sheet in normalized condition, including laser-cut holes with hardened edges
• Optimized flare geometry delivers maximum panel stiffness and strength
• Manufactured from premium hardened high-carbon tool steel for long tool life
• Ergonomic profile designed for ease of handling during use
• Compatible with sheet up to .090" chromoly or .125" mild steel

Engineered from the ground up by SPC Performance, these large-format dimple dies are the professional choice for fabricators who demand precision, repeatability, and reliability across demanding materials. The 15815 set pairs with the SPC 15810 set (0.75"–2.5") to form a complete flared hole die collection.