Guides & References

Visual reference

Identify heads and drives from diagrams (complements the guides below).

• Reference hub
• Screw head types
• Screw drive types
• Screw head shapes (profiles)

All guides

• Metric vs Imperial Fasteners
• Bolt Head Markings
• Thread Pitch Explained
• Why Stainless Bolts Gall
• Bolt vs Screw Difference
• Thread Types Explained
• How to Measure Thread Pitch
• What Is TPI
• Tap Drill Basics
• Fastener Materials Guide
• Metric Thread Tolerances
• Bolt Strength Grades