BA Thread Calculator - British Association Threads.

Enter Thread Data:

The BA is now obsolete but often used in model making. Unlike the 60° form of Metric and Unified threads, these have an included angle of 47½°. The crests and roots are rounded with an equal radii.

The External threads can be toleranced to Close Class 0, Normal Class 0 or Normal Class 11. The Internal threads are all of a single tolerance class.

Select BA Thread Designation: 0 BA 1 BA 2 BA 3 BA 4 BA 5 BA 6 BA 7 BA 8 BA 9 BA 10 BA 11 BA 12 BA 13 BA 14 BA 15 BA 16 BA

Select External Class or Fit: Close Class 0 - to 10 BA Normal Class 0 - to 16 BA

Applied Preload (N): Coefficient of Friction (µ): -

BA Thread Data
Nominal Diameter:	mm
Nominal Pitch:	mm
		Max	Min
External Thread Data
Major Diameter (MD):	mm
Pitch Diameter (PD):	mm
Minor Diameter (MN):	mm
Internal Thread Data
Major Diameter (MD):	mm
Pitch Diameter (PD):	mm
Minor Diameter (MN):	mm
Depth of Thread:	mm
Crest/Root Radius:	mm
Thread Loading
Tensile Stress Bolt Area:	mm²
Stress In the External Thread:	N/mm²
Shear Stress Area (3 x Pitch Contact):	mm²
Shear Stress In the Internal Thread:	N/mm²
Torque to Tighten:	Nmm

Calculate