Tap drill sizes, thread dimensions, and tightening torque reference
| Size | Pitch (mm) | Major Ø (mm) | Pitch Ø (mm) | Minor Ø (mm) | Tap Drill (mm) | Clearance (mm) |
|---|
Tap drill diameter is calculated for approximately 75% thread engagement (standard for most applications): tap drill = major diameter − pitch. Higher engagement increases strength but also tapping torque and tap breakage risk.
Clearance drill sizes allow a bolt to pass freely through a part. Torque values assume clean steel fasteners; lubrication, coatings, and joint design significantly affect actual clamp load.