This week's selection is the Four Jaw Self Centring Chuck by UK Thingiverse creator hexitex. The Four Jaw Self Centring Chuck is not a new item, having been designed in 2011, so we'll classify it as an "oldie".
The purpose of this design is literally its name. It's a chuck used to solidly grasp objects that self centers when operated. The video here shows how it works.
It's a crafty way to manufacture a useful chuck. This all occurs by 3D printing and assembling only four printed parts. You'll need a few nuts and bolts, too, of course.
Even better, the "Jaws" can be redesigned and replaced to accommodate a variety of different subjects. Hexitex says:
The design is based on the Longworth Chuck, it's a great movement and normally used for Woodturning… I added my take on the design by giving it more mass, taken away the need for wingnuts (making it safer) and generally done as much as possible to make it useful - The nice thing about this design is that it could be made in any material with very little changes to the file. It's a good size chuck maxing out at the makerbot's 10cm build surface wide and 7cm tall.
We like this design because it is straightforward to 3D print, yet results in a practical, kinda-complex piece of machinery you may actually use. All made on your own 3D printer.
You'll find the Four Jaw Self Centring Chuck available for free download at Thingiverse.