Overview
The Lawson 5/8-11 x 5 hex cap screw is a Grade 8 alloy steel fastener engineered for demanding industrial applications. Finished with Perma Plate coating for superior corrosion resistance, this capscrew delivers the high-strength, vibration-resistant performance required in machinery, equipment assembly, and critical maintenance operations. Supplied in a convenient box of 10 units.
Key Features
- Grade 8 alloy steel construction – minimum 150,000 PSI tensile strength for high-load applications
- Perma Plate corrosion protection – yellow zinc finish for extended service life in industrial environments
- UNJ thread design – fatigue and vibration-resistant for critical assemblies
- 20% higher wrenching surface – hex head with 15/16″ across flats for improved torque distribution and safety
- Heat-treated and tempered – consistent strength and reliability across the entire batch
- Proprietary head marking – easy identification and traceability for specification compliance
- Easy alignment and assembly – increased chamfer length and trailing thread design for streamlined installation
- Matched fastener system – compatible with Lawson Grade 8 nuts, flat washers, and lock nuts for complete assemblies
Technical Specifications
- Thread Size: 5/8-11 UNC (Unified National Coarse)
- Length: 5 inches
- Head Style: Hex cap
- Material: Alloy steel
- Grade: Grade 8
- Finish: Perma Plate (yellow zinc)
- Tensile Strength: Minimum 150,000 PSI
- Head Height: 15/32 inch
- Across Flats: 15/16 inch
- Quantity per Box: 10 pieces
- Minimum Threaded Length: (2 x Diameter) + 1/4″ = 1.5 inches
Typical Applications
- Heavy equipment assembly and structural bolting
- Machinery maintenance and repair
- Automotive and industrial equipment fastening
- Vibration-prone applications requiring fatigue resistance
- Outdoor and corrosion-prone environments (Perma Plate protection)
- OEM and aftermarket assembly operations
Compatibility & Replacements
Compatible With
- Lawson Grade 8 matching nuts and washers
- Standard 5/8-11 UNC threaded assemblies
- Industrial machinery and equipment requiring Grade 8 strength
- SAE and ASTM Grade 8 specifications
Replaces / Drop-In Replacement For
This screw conforms to Grade 8 hex cap screw standards and is interchangeable with any 5/8-11 x 5 Grade 8 fastener meeting SAE J429 and ASTM A449 specifications. Verify exact application requirements with your system integrator before ordering.
Works With
- Grade 8 hex lock nuts (5/8-11)
- Grade 8 flat washers (5/8 ID)
- Grade 8 lock washers (5/8 ID)
- Standard SAE and ISO fastening systems
- Lawson Tuff-Torq matched component system









