TIME2: A 3D-printed weight-driven clock with key winding and an hourly bell

TIME2 is the next version of TIME, my open-source 3D-printed clock. It keeps everything that made TIME work: the deadbeat escapement with its one-second tick, the 60:1 going train, the weight drive and the bolted six-click ratchet. The new version fixes the things that bugged me after a year of living with it, it runs on a single wind for 3 days and is now, really easy to wind up. The Bell on the hour is also a stand out feature, making it easy to set the bell ring. As ever with such models its a work in progress, my version has been happily running for a month before publishing this model. What's new - Key winding through the dial. A winding arbor runs through the front frame into a square socket in the barrel. Wind it like a real clock, about 14 turns for 3 days.

- Set the hands while it runs. A friction-fit cannon pinion carries the minute hand. Just turn the hand.

- Optional hourly bell. A passing strike: one blow on the bell each hour. The lifting cam grips a keyed collar on the centre wheel, so you twist it to choose the minute (6 degrees = 1 minute). No glue, no stopping the clock.

- Carbon-fibre arbors and a straight barrel arbor.

- A printed 2.5 kg weight. A screw-lid shell holds a neoprene dumbbell, with a bolt-on loop for the hook.

- Fewer bought parts. Printed bushes replace the centre arbor bearings; the clock itself needs one bearing.

- A key peg that holds the key on a dummy winding square.

Two ways to build - New build: download the TIME2 files and follow TIME@_Build_Guild.pdf: a 10-page guide with shopping list, print settings, parts list, 8 illustrated steps, troubleshooting, and the bell as an optional final section.

- Already have TIME? Download the TIME to TIME2 Upgrade files. Part 1 upgrades the clock (6 new parts; you keep your rods, train, escapement, great wheel and clicks). Part 2 adds the bell.

Print settings Setting Value

Printer Fits a Prusa MK4 (250 x 210 mm). Turn the back plate about 50 degrees on the bed

Layers 0.15-0.2 mm (0.15 or 0.1 mm for wheels and the front frame)

Walls 3; 4 on the barrel and weight shell

Infill 25-40% gyroid. Hammer arm 80%. Bob and hook loop 100%

Material PLA; PETG for clicks, bushes, barrel, winding arbor, key, cannon pinion and weight parts

Supports None, except under the hammer head

Every STL is numbered in build order and already oriented for printing. Files ending PRINT6 or PRINT2 are printed six or two times. You will also need - 1 x 624ZZ bearing (4 x 13 x 5 mm) for the anchor; 2 more for the bell

- About 500 mm of 3 mm pultruded carbon-fibre rod

- M4 screws (about 13 x 8 mm, 6 x 10-12 mm with nuts), 4 M4 washers, 2 sets of M3 x 10 bolts, nuts and washers

- 2 x 10 mm beech dowels, 1 m long, for the pendulum

- About 1.5 m of braided line and a 2.5 kg hex dumbbell (under 200 mm long)

- An 85 mm counter bell (bell only), a wooden board and wood screws

Notes The clock hangs with its back plate horizontal and the bell at the top. The weight hangs on the left of the barrel and you wind clockwise. Full details, the parts list and troubleshooting are in the guides. Designed in Fusion 360 and built and tested on my own clock. If you build one, please post a make: I'd love to see it. The full story is on digitalurban.org (incoming).