Pro Metric Fastener Assistant | Hex Key & Drill Size Calculator Mechanical Fastening ToolsPro Hex Key Assistant Socket Head Button Head Flat Head Thread Diameter (Metric) M3M4M5M6M8M10M12M16 Clearance Fit Class Close (Precision)Normal (Standard)Large (Loose) Required Hex Key5 mm Tap Drill (Pilot) 5.0 mm Clearance Hole 6.6 mm
