TABLE 1
MAXIMUM SAFE TORSIONAL
LOADS BASED ON #303 STAINLESS STEEL
WITH Smax = 12,000 PSI AND GRADUALLY APPLIED LOAD
| Shaft Diameter (inches) |
1/16 | 3/32 | 1/8 | 5/32 | 3/16 | 7/32 | 1/4 | 5/16 | 3/8 | 1/2 |
| Tmax | 0.56 | 1.89 | 4.60 | 8.93 | 15.64 | 24.38 | 36.77 | 71.46 | 124.1 | 295 |
The maximum torques in
this table can be converted to horsepower for a given value of N (RPM) by the power
Nomogram given in the Designer Data Section of this book.
(d) Combined Torsional and Bending Loads
Combined bending and torsion arises as a result of
component weight, belt tension, gear-tooth forces, etc. In that case shaft size can be
determined from the equation:
d = [ 5.1 ((KmM)² + (KtT)² )1/2]1/3
(5)
Smax
where the values of the shock factors (Km, Kt) are
given in the following table:
TABLE 2
SHOCK FACTORS VS. TYPE OF LOAD
| Type of Load | Km | Kt |
| Gradually applied load |
1.0 | 1.0 |
| Minor shocks, sudden load |
1.4—2.0 | 1.0—1.5 |
| Heavy shocks, sudden heavy loads |
2.0—3.0 |
1.5—3.0 |
If we arbitrarily consider only minor shock loads and assume that Km = Kt = (2)½ @ 1.41 and (as before) Smax 12,000 psi, the combined allowable bending and torsional moments can be related to shaft size as shown in the following table: