Most clocks give their hands somewhere obvious to stand, usually a solid face hiding the mechanism behind it. Hollow Clock V leaves that space empty, making its hands appear to hover inside a slender ring. This working DIY project uses 3D-printed parts, hidden gears, and magnets to pull off a trick that doesn’t require a transparent panel to work.
The minute hand provides the first clue, since its outer end connects to a rotating ring concealed within the frame. Its center supports the hour hand on a small pivot, so the pair isn’t actually levitating. The hour hand’s position is controlled magnetically by another rotating ring, allowing it to keep pointing at the right hour while the longer hand travels around.
Designer: Shinsaku Hiura
That second ring carries two neodymium magnets, which interact with a third tucked into the hour hand. Their T-shaped arrangement helps keep the hand aligned without adding a connection across the opening. Down in the base, a stepper motor and a combination of worm and bevel gears drive the minute ring 12 times faster than the hour ring, without a bulky central hub.
All that machinery makes the spare appearance deceptive. The ring has a border only about 0.28 inches wide, with hour markers replacing a conventional numbered dial. Screws are kept out of sight when the clock is assembled, apart from the central hand fastener. A rear USB-C connection sends the cable away from the front, leaving the open center to do the distracting.
The finish is also shaped by the way the parts are printed, rather than treated as an afterthought. Front surfaces sit against the printer’s build plate, picking up its texture instead of exposing filament paths across the face. Changing filament during printing gives the markers a contrasting color. It’s a small manufacturing decision that makes the homemade object look a little more deliberate.
Setting the time stays physical, too. You lift the display ring out of the base, freeing it from the drive gears, move the hands to the desired time, and slot it back in. There’s no tiny adjustment knob to hunt for behind the housing. For a clock that hides so much of its mechanism, this particular interaction is refreshingly easy to understand.
Getting to that point takes more effort than the finished clock lets on. The project involves printing, soldering, loading firmware, and assembling the moving parts, although the supplied print orientations don’t require supports. Smooth gear surfaces matter, and the guide includes lubrication and tuning advice. The uncluttered desk ornament is also a small mechanical project, with patience required before it starts keeping time.
The ratchet is designed to compensate for missed motor steps, though it also introduces a reason to think twice about bedside placement. The guide describes removing its hook for quiet operation only when the mechanism runs smoothly enough. On a desk or shelf, that choice comes down to how much of the clock’s engineering you’re prepared to hear as well as admire.