Keyways Index
Table showing keyway / spline design factor Kd
| Coupling Design | Design Factor Kd |
| Fixed (close fit) loaded No relative axial/radial movement of the hub and the shaft occurs.; the relative positions of the shaft and hub are fixed using a suitable bearing or constructional design e.g press-fit , Shaft nuts. | 1 |
| Flexible/Sliding - Unloaded Relative positions of the shaft and hub are not fixed; Axial movements of the hub along the shaft occur only when coupling is unloaded. The shaft is effectively fixed when loaded. | 3 |
| Flexible/Sliding loaded Sliding coupling with loading:relative positions of the shaft and hub are not fixed; axial shifts of the hub along the shaft occur in loaded couplings. | 9 |
Table showing spline application factors Ka
| Power Source | Type of Load | |||
| Uniform Generators, Fans |
Light shock Oscillating pumps |
Intermittent Shock Actuators | heavy shock Presses, Shears | |
| Application Factor (Ka | ||||
| Uniform (Turbine, Motor) | 1,0 | 1,2 | 1,5 | 1,8 |
| light shock, (Hydraulic Motor) | 1,2 | 1,3 | 1,8 | 2,1 |
| Medium shock, (Internal combustion engine | 2,00 | 2,2 | 2,4 | 2,8 |
Table showing splines distribution factors Km
This factor relates to reduction in strength as a result of misalignment of the spline
| Misalignment (mm/mm | Load misalignment factor (Km ) | |||
| 12mm face width | 25mm face width | 50mm face width | 100mm face width | |
| 0,001 | 1,0 | 1,0 | 1 | 1,5 |
| 0,002 | 1,0 | 1,0 | 1,5 | 2,0 |
| 0,004 | 1,0 | 1,5 | 2,0 | 2,5 |
| 0,008 | 1,5 | 2,0 | 2,5 | 3,0 |
Table showing fatigue life factors for splines Kf
| No of torque cycles (stop/start cycles) | Fatigue life factor (Kf ) | |
| Unidirectional | Fully reversed | |
| 1 000 | 1,8 | 1,8 |
| 10 000 | 1,0 | 1,0 |
| 100 000 | 0,5 | 0,4 |
| 1 000 000 | 0,4 | 0,3 |
| 10 000 000 | 0,3 | 0,2 |
Table showing wear life factors for splines Kw
| No revolutions of spline | Life wear factor (Kf ) |
| 10 000 | 4,0 |
| 100 000 | 2,8 |
| 1 000 000 | 2,0 |
| 10 000 000 | 1,4 |
| 100 000 000 | 1,0 |
| 1000 000 000 | 0,7 |
| 10 000 000 000 | 0,5 |
Table showing Typical design strengths for selected materials
| Material | Hardness | Ultimate Tensile Strength |
Permissible Compressive Strength |
Permitted Shear Strength | Brinell | Rockwell C | MPa | MPa | MPa |
| Structural Steel | 150-200 | - | 350 | 90 | 140 |
| Carbon Steel | 220-270 | - | 500 | 130 | 200 |
| Alloy Steel | 300-350 | 33-38 | 600 | 200 | 275 |
| Surface Hardened Steel | 650 | 45-53 | 650 | 250 | 275 |
| Cast Iron (Speroidal Graphite | 400 | - | 400 | 135 | 140 |
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