when the maximum shear stress in a bi-axial stress system reaches the shear stress at elastic limit in a simple tension test

when the maximum principal stress in a bi-axial stress system reaches the elastic limit of the material in a simple tension test

when the strain energy per unit volume in a bi-axial stress system reaches the strain energy at the elastic limit per unit volume as determined from a simple tension test

when the maximum principal strain in a bi-axial stress system reaches the strain at the elastic limit as determined from a simple tension test

pitch circle to the top of a tooth

pitch circle to the bottom of a tooth

top of a tooth to the bottom of a tooth

addendum circle to the clearance circle

cotter joint

knuckle joint

universal joint

flange coupling

normal pitch

axial pitch

diametral pitch

module

Euler's formula

Rankine's formula

Johnson's straight line formula

Johnson's parabolic formula