I’ve been thinking about materials a lot lately, specifically materials that people tend to already have or at least won’t have to take any special measures to obtain. Use of such materials makes a project infinitely more reproducible in MacGyver situations.
The caps on the plastic bottles I go through plenty of at work just caught my attention. On each bottle is a pre-matched two-piece threaded fastener rendered in recyclable plastic. The bottle end is, when cut as pictured, a wide-mouthed funnel. Cut down even further, it might even be suitable as a makeshift flanged bearing. Judicious application of a drill, screws, hammer and nail, epoxy or other strong glue, or similar to either the cap or the bottle could easily turn the pair into a very useful ad hoc adapter for some mechanical apparatus.
I also happen to take a wide variety of different medications for my various conditions, and so have a large and growing assortment of pill bottles, most with child-resistant caps. I see these bottles having interesting possibilities for many of the same reasons and additionally as project cases.
Plus, at home we have an ever-increasing number of battery-operated devices of which each has a Phillips screw to secure the battery door, presumably for the child-resistance factor. I think that with a little experimentation and some strong, permanent adhesive, these devices could be altered to use a child-resistant cap instead. It’s not as if we don’t have the proper screwdrivers available, but it would be great if this process didn’t require tools.
(On that topic, if you’re in a home without children, the child-resistant action of the traditional two-piece “push down and turn” sliding cap can be defeated by installing a nail/screw/tack into the top of the cap, preferably off center, through the bottom. This synchronizes the motion of the grip to the inner cap, making them effectively one piece in much the same way that pushing down does. Enjoy if you can!)