This is yet another self-resetting mouse trap! The design is based around 3/4" non-metallic conduit as the roller "bar" and 608 style bearings (skateboard / inline skates). A search for " 608-2RS " will yield the bearings used in this design. Because this is a parametric design, you are free to use other "pipe" sizes as well as bearings as long as you provide accurate dimensions!

The critical dimensions are highlighted with red in the design parameters "spreadsheet" in FreeCAD. All values can be edited.Topological naming issues plague the changing the ramp angle (breaks the ramp screw hole sketch due to datum plane change).

Non-printed parts required:

• 3/4" non metallic conduit (approx 250mm or 10")
• 2 x 608-2RS bearings
• 5 gallon bucket
• approximately 2L of RV / plumbing antifreeze

The design was done in FreeCAD and as mentioned it is fully parametric. I have included the FreeCAD file so that you can modify the design to your heart's content. While the design is far from perfect, it is functional.

I am open to any suggestions as to how to improve the design work-flow in FreeCAD.