A diy hollow clock with a slim display ring, its motor and gears hidden within the hollow center.

Hollow Clock V Hides Its Motor and Gears Behind a Slim Display Ring

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Written by Seth Sebastian

2026-11-10

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Most clocks give their hands a solid face to sit on. Hollow Clock V replaces that face with a slim ring, so the hands appear to hang in empty space. The effect comes from a diy hollow clock build that combines 3D-printed parts, concealed gears, and magnets.

How the hidden drive works

The minute hand connects at its outer end to a rotating ring hidden inside the frame. Its center rests on a small pivot that carries the hour hand. Nothing is truly floating.

If you enjoy seeing concealed motion turned into a visible showpiece, Retro AKAI Tape Deck Rebuilt as a Moving LEGO Model shows a similarly hidden, hands-on mechanism brought to life.

The hour hand is positioned by a second ring that turns on its own track. A pair of neodymium magnets sits in that ring, and a third magnet is set into the hour hand. Their T-shaped layout keeps the hand aligned without a physical link across the opening.

Designed by Shinsaku Hiura, this hidden gears clock places its motor out of sight. A stepper motor in the base drives a combination of worm and bevel gears. Those gears turn the minute ring 12 times faster than the hour ring, and no bulky central hub is needed.

The visible details are deliberately sparse. The display ring’s edge is about 0.28 inches wide, and hour markers take the place of printed numerals. Once assembled, the only exposed fastener is the one that secures the central hand. The USB-C port sits at the back, so the cable stays away from the front.

Close-up of the clock's slim ring showing the thin gap around the hollow center.
Hollow clock mounted on a wall, showing its display ring from the side.

Finish and setup

The printing orientation affects how the clock looks. The front faces are printed flat on the bed, so their surfaces inherit the bed’s finish instead of showing filament trails. A filament change partway through the print gives the hour markers a contrasting color.

Setting the time on a diy hollow clock is a hands-on task. Lift the display ring out of the base, which disengages it from the drive gears. Turn the hands to the correct time, then seat the ring again. No small adjustment knob is hidden behind the housing.

Building a diy hollow clock takes patience

The finished project looks simple, but building it involves several stages. Makers print the parts, solder the electronics, load the firmware, and assemble the moving parts. The guide’s print orientations don’t require supports.

Gear surfaces need to be smooth before the clock runs reliably. The guide includes lubrication and tuning steps for that work. Builders should expect a fair amount of adjustment before it keeps accurate time.

A ratchet compensates for motor steps that the drive misses. The guide says its hook can be removed for quieter operation, but only once the mechanism moves freely. That makes noise a practical concern for anyone considering a bedside placement.

Precise timekeeping mechanisms like these have a long lineage, and Patek Philippe’s Exclusive Ref. 5978P-010 Perpetual Calendar offers a luxury counterpoint worth comparing for anyone fascinated by intricate clockwork.

Release terms and the creator’s concerns

A post on the Adafruit blog, dated June 12, 2024, reported the release of the Hollow Clock V video. The post said the creator, who goes by shiura, had been concerned about the previous version, Hollow Clock 4. Several videos had sold that design without permission or without naming the original.

The post said the creator would emphasize the license conditions for the new design. It also said the data would be released later, as usual. The same post listed the 3D files and code as published on Instructables, Thingiverse, and Printables, and it linked an assembly guide and a printing timelapse. The post does not explain how those two statements fit together.

For a reader, the clock design shows how much a mechanism can hide. The release notes show how its designer wants the work shared.

A diy hollow clock with a slim display ring, its motor and gears hidden within the hollow center.

H/T yankodesign.com

Frequently asked questions

How does the hour hand stay aligned without a physical connection?

The hour hand is positioned by a second ring that turns on its own track. A pair of neodymium magnets sits in that ring, and a third magnet is set into the hour hand. Their T-shaped layout keeps the hand aligned without a physical link across the opening.

Where is the motor and how does it drive the minute ring?

A stepper motor in the base drives a combination of worm and bevel gears. These gears turn the minute ring 12 times faster than the hour ring, and the motor stays out of sight.

How do you set the time on this hollow clock?

Lift the display ring out of the base, which disengages it from the drive gears. Turn the hands to the correct time, then seat the ring again.

Can the hollow clock be made quieter during operation?

The guide says the ratchet’s hook can be removed for quieter operation. However, this should only be done once the mechanism moves freely.

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