All Goofy Bolts are based on a cartoon sketch I remember from a long ago drafting class where there were different bolts for different hole types.
June 2016's Goofy Bolt features a 'Knurled Head For Pliers And Vise-Grips.'
Goofy Bolts are hollow where possible to save you money, and come with at least one hole plug to plug the end if you are not using a 4mm (5/32") rod to mount the bolt for display. The best way to mount your Goofy Bolts is to glue them to a mounting surface at the hole locations on the PDF template that can be downloaded and printed https://www.shapeways.com/forum/index.php?t=msg&goto=135215#msg_135215 The next best method is to use 4mm x 0.7 nuts on the mounting posts; but be careful as some 3D printing processes don't replicate the threads as cleanly as they were modeled.
Nylon is ideal for the budget minded collector that is willing to give up crisp detail. For the ultimate 3D printed representation of what was modeled, choose one of the 'frosted detail' plastics. For decorations used outdoors, one of the steel materials is best suited for this purpose. For a unique gift, choose a semi precious metal.
All Goofy Bolts are for decoration only, and shouldn't be used as fasteners.