
Metric units
Joint allowable stress

Shear stress from force

Shear stress from moment

Resulting reduced stress

Strength check
τ red ≤ τ A
Minimum step depth

| Design of optimum overlap length | |
| Anticipates that a joint is designed so that any breakage occurs in the joint itself, and not in the basic material. | |
| L opt = max {L min , L 1 } | |
| where: | |
|  | |
Meaning of used variables for metric units:
| S Us | Joint strength in tension [MPa] | 
| k S | Shear safety factor | 
| S Ub | Tensile strength of basic material [MPa] | 
| F | Transferred force [N] | 
| d | Step diameter [mm] | 
| L | Step depth [mm] | 
| T | Torque [MPa] | 
English units
Joint allowable stress

Shear stress from force

Shear stress from moment

Resulting reduced stress

Strength check
τ red ≤ τ A
Minimum step depth

| Design of optimum overlap length | |
| Anticipates that a joint is designed so that any breakage occurs in the joint itself, and not in the basic material. | |
| L opt = max {L min , L 1 } | |
| where: | |
|  | |
Meaning of used variables for metric units:
| S Us | Joint strength in tension [MPa] | 
| k S | Shear safety factor | 
| S Ub | Tensile strength of basic material [MPa] | 
| F | Transferred force [N] | 
| d | Step diameter [mm] | 
| L | Step depth [mm] | 
| T | Torque [MPa] |