Physical Fit Testing Blocks

[Update 31-07-2020] Updated the OpenSCAD file so that it works with the Thingiverse Customizer. For some reason it worked fine in OpenSCAD, but caused syntax errors in the online version. Anyway, it's fixed and working now.

This is a really simple tool that I've found useful in eliminating some messing around when designing something to fit a physical object with a given amount of slack.

For example, say you have a metal rod or a hex bit from a drill that you want to "fit" into your 3D printed object. You measure the item with calipers, which gives you the size for the design, but you're not too sure what the actual "fit" will be like when it's printed out.

Sometimes you want a loose fit, which will be loose enough to allow the item to slide freely, but not so loose that it will wobble around in the hole. Sometimes you want a tight fit, so the item will go into the hole, but not come loose without some small amount of force (like the "grip " between Lego bricks). And sometimes