Marine Fasteners RP-81 5/16-18 x 2in 18-8 Stainless Steel Hex Cap Screw 25-Pack

The Marine Fasteners RP-81 is a 5/16-18 x 2-inch hex head cap screw manufactured from 18-8 stainless steel, sold in a convenient 25-piece pack. Engineered for corrosion resistance in demanding marine, coastal, and outdoor environments, these fasteners deliver reliable clamping strength wherever exposure to moisture, salt air, or the elements is a concern.

Hex cap screws differ from standard hex bolts in two important ways: they feature a machined washer bearing surface on the underside of the head and a chamfered thread end, and they are held to tighter dimensional tolerances per ASME B18.2.1. This makes them the preferred choice for precision assemblies and applications where joint integrity matters.

Key Features:

• Material: 18-8 (304) stainless steel — excellent resistance to rust, corrosion, and oxidation
• Size: 5/16-18 UNC (Unified National Coarse) x 2 inches
• Head Style: Hex head cap screw with machined bearing surface
• Drive: 1/2-inch hex wrench or socket
• Thread: 18 threads per inch, coarse pitch
• Quantity: 25 pieces per pack
• Standard: Dimensionally conforming to ASME B18.2.1

18-8 stainless steel provides an excellent balance of strength and corrosion resistance, making these screws well-suited for boat building, dock hardware, marine equipment assembly, and any outdoor fastening application where longevity and appearance are important. The coarse 5/16-18 thread engages quickly and is highly resistant to cross-threading, making installation straightforward in the field.