<h2>Overview</h2>
<p>The <strong>Lawson Tuff-Torq Grade 8 Hex Cap Screw 5/8″-11 x 4″</strong> is a high-strength alloy steel fastener engineered for demanding maintenance, repair, and construction applications. This Grade 8 screw meets or exceeds minimum 150,000 PSI tensile strength, making it ideal for critical fastening where reliability and durability are essential. Manufactured by Lawson Products, a leader in industrial fasteners, this premium hex cap screw delivers consistent performance across manufacturing, OEM, and field service environments.</p>
<h2>Key Features</h2>
<ul>
<li>Grade 8 alloy steel construction—meets or exceeds 150,000 PSI minimum tensile strength</li>
<li>Heat-treated and quenched-and-tempered for superior fatigue and vibration resistance</li>
<li>Perma-plated zinc finish for enhanced corrosion protection in industrial environments</li>
<li>Fatigue/vibration-resistant UNJ thread design with trailing thread chamfer for easier assembly</li>
<li>20% higher-than-normal wrenching surface for increased safety and even torque distribution</li>
<li>Proprietary head marking for traceability and inventory control</li>
</ul>
<h2>Technical Specifications</h2>
<ul>
<li><strong>Thread Size:</strong> 5/8″-11 (coarse thread)</li>
<li><strong>Length:</strong> 4 inches</li>
<li><strong>Grade:</strong> Grade 8</li>
<li><strong>Material:</strong> Alloy steel</li>
<li><strong>Finish:</strong> Zinc plated (Perma-Plated)</li>
<li><strong>Tensile Strength:</strong> Minimum 150,000 PSI</li>
<li><strong>Thread Type:</strong> UNJ coarse thread with improved fatigue resistance</li>
<li><strong>Across Flats (Hex):</strong> 15/16 inch (standard for 5/8″ diameter)</li>
<li><strong>Head Height:</strong> Approximately 31/32 inch</li>
<li><strong>Quantity Per Box:</strong> 10 pieces</li>
<li><strong>Manufacturer:</strong> Lawson Products, Inc. (USA)</li>
</ul>
<h2>Typical Applications</h2>
<p>Grade 8 hex cap screws are the preferred fastener for high-stress, vibration-prone environments:</p>
<ul>
<li>Heavy machinery assembly and repair</li>
<li>Automotive and industrial engine work</li>
<li>Structural steel fabrication and erection</li>
<li>Equipment frame and mounting applications</li>
<li>Hydraulic and pneumatic equipment fastening</li>
<li>Bearing housings and critical joint work</li>
<li>OEM component assembly requiring consistent tensile performance</li>
</ul>
<h2>Compatibility & Replacements</h2>
<h3>Compatible With</h3>
<ul>
<li>Grade 8 matching nuts (metric and imperial)</li>
<li>Grade 8 flat and lock washers</li>
<li>Standard hex sockets and wrenches (15/16″ across flats)</li>
<li>All fastening applications requiring Grade 8 strength and vibration resistance</li>
</ul>
<h3>Replaces / Drop-In Replacement For</h3>
<ul>
<li>Other Grade 8 hex cap screws 5/8″-11 x 4″ from competing manufacturers</li>
<li>OEM-specification hex cap screws in equipment requiring Grade 8 fasteners</li>
</ul>
<h3>Works With</h3>
<ul>
<li>SAE J429 Grade 8 specification compliance</li>
<li>ASTM A354 Grade BD fastener standards</li>
<li>ISO 4017 metric equivalents (M16 x 100mm)</li>
<li>All standard industrial maintenance and assembly workflows</li>
</ul>
