Bill & FDMSIV,Bill Edmundson wrote:P is you lifting force at the center. P/2 on each end. The distance from the end to the lift point is L/2. M= force x distance or P/2 x L/2 = PL/4

It's hard to believe that I made a living for almost 34 years on variations of one equation. Stress = P/A -+ MC/I.

Bill

Not to make this thread any more cumbersome but I really do need to understand this equation. Please address what parts I'm not following on:

I assume that the loads on the end of the beam are treated as if it were a simple cantilever force? (In two directions)

P= Force, which we are solving for in "reverse" because of the safety limitation to 10Kpsi?

I'm stabbing at this, combining both of your responses and reviewing the formulae as posted in this thread and this is where I'm getting lost, as per my question marks

FDMSIV: (Yield strength of material / safety factor) * 3.86 * 4 * (1 / 96) * 10000 (I'm assuming your original post of 1000 was a typo, as changing the value to 10K gave a sum of 1608 pounds, not 160.83 pounds)

Sectional Modulus * ? * ? * (?) * 10000 (Ok, you see I'm in trouble)

Where:

3.86 = 2(sec. mod. as posted in manuals)

4 = ? is this my 1/2 length expressed in feet?

(1/96) = ? The beam (overall) is expressed in inches? Why is it expressed as a fraction?

10,000 equals strength of material, reduced by a safety factor of five.

The reason I'm asking all these questions is because I need to be able to duplicate this on a fairly regular basis.