Multiply the weight to be supported in pounds by the length of the cylinder between the supports in feet; divide the product by .6 of the value of material, and the cube root of ¼ of the quotient will give the diameter.

Note,-When the cylinder is loaded uniformly along its length, the cube root of half quotient will give the diameter.

Example

What should be the diameter of a cast-iron cylinder, 2 feet between the supports, that will support 54000 lbs. without permanent injury?

64000X2 800

----------=800, and 3√- = 5.85 ins.

.X225 4

And what its diameter if loaded uniformly along its length? 800+2 -------=100, and 3√ 100=4.64 ins.