...
Using a material with a high modulus of elasticity (increasing stiffness).
Increasing the area moment of inertia. This is the smallest cross-sectional area moment of inertia for the column. For a circular column this would typically be constant throughout the piece. This varies heavily with radius.
Reducing the length of the column (ensure that you calculate the length from fixture to fixture, not just the ends of the column).
Changing the end conditions.
Calculating the k K value:
For long columns,
...
What is this based on?
When compressed, columns will fail by buckling in a sinusoidal wave. The formula expects the KL term (together) to represent half of the wavelength of this failure wave.
...
The k K factor is a representation of how much of the failure wave is expressed in the column length. If you are ever faced with an ambiguous case, consider how large the failure wave would be. For a pushrod with two rod ends, the k K value is 1.
Additional considerations for internal threading:
...