PVC Pipe Bracket

I created these brackets for building a "dry box" to hold my filament (it is humid in Hawaii). They are surprisingly strong. The Solidworks file contains 3 configurations, one for each pipe diameter. All the dimensions are driven from equations. PVC pipe is not an engineering material; the dimensions vary wildly between manufacturers. The two most important equations are PVC_pipe_diameter and Nub_diameter. The "nub" fits into the pipe and prevents the pipe from lifting out accidently or bowing i