3/8"-16 x 3-1/2" Grade 8 Bolts (10-Pack) – Heavy-Duty Hex Bolts Includes Flat Washers & Nylon Lock Nuts – High-Strength SAE Anti-Vibration 3.5" Coarse Bolts for Automotive, Machinery & Construction

These 3/8"-16 x 3-1/2" (3.5") long Grade 8 (G8) Bolts are engineered for applications where strength, reliability, and vibration resistance matter most. Each pack combines a high-strength Grade 8 (G8) hex bolt, a matching nylon locking hex nut, one flat washer for load distribution. Designed for use in automotive repairs, trailer builds, agricultural equipment, shop machinery, and structural assemblies, this kit eliminates the need to source parts separately—saving time while ensuring proper fit and performance. Whether you’re a professional mechanic, fabricator, or serious DIYer, this fastener kit delivers the confidence of industrial-grade hardware in a convenient, ready-to-use package.

• Complete 10-packs: Includes 10 Grade 8 hex bolts, 10 hardened flat washers, and 10 nylon Grade 8 lock nuts — everything you need for strong, vibration-resistant fastening in one convenient pack. Bolts 3/8" x 3.5" long. Nuts and washers fit 3/8" bolts.
• Grade 8 Strength for Demanding Jobs: High-tensile SAE J429 Grade 8 bolts and nuts deliver superior load capacity and shear strength, making this kit ideal for automotive, trailer, machinery, and structural applications. All washers are hardened, which is compatible with a Grade 8 fastening system. Threads are made to the requirements of ASME B1.1. ASME B18.2.1 Dimensional Requirements. SAE J429 Material and Strength Level. ASTM A564 Material and Strength Level. ASTM F788 Surface Discontinuities. ASME B18.18 Inspection and Quality Assurance.
• Utimate Anti-Vibration Nylon Locking System: washers help prevent loosening under torque, shock, and movement — perfect for equipment that sees constant vibration or cyclic loads.
• Precision-Matched Components: All fasteners are 3/8"-16 UNC for reliable fit and consistent clamping force across every assembly — no mismatched hardware, no guesswork.
• Built for Pros & Serious DIYers: Whether you’re repairing equipment, building fixtures, or assembling heavy components, this kit delivers industrial-grade reliability in a compact, easy-to-store format.