Analysis
While many aspects of the design were looked at for this project, including material strength, weldability, point load to cause tipping, and stress analysis, there were two primary concerns. These concerns stemmed from the goal of being able to safely load 800 pounds onto the table. The first concern being the shear strength of the ACME threads being used. Second, what the allowable load would be upon doing a column analysis.
The ACME thread shear analysis was surprisingly straight forward due to the fact that they are so incredibly standardized, knowing the type of rod that was being used it was a few calculations, shown to the right, to determine what the shear strength of the threads would be. The values for the total shear area was determined using the fact that I would be using an interior nut with 0.75" of length, and the tensile strength was gathered from Matweb using the material that the ACME thread was designated to be made out of. The force to failure had a result of being much higher than anticipated and working under normal conditions would never be reached.
The column analysis that was done was using the MDESIGN software by Mott. The dimensions chosen were from the solid core in center of the threads, meaning that the major diameter of the rod was taken, and then the depth of thread was taken from both sides and subtracted from the major diameter to look worst case scenario where none of the threads were providing support to the structure. The values for allowable load with a safety factor of 2.5 came out to be 816lbf for a single column. With a safety factor this high, as well as there being a second column supporting the structure the allowable load of 800lbf was well within bounds.
