About the Metronome Engine
This started as a test rig: a clockmaker wanted to check his compound-pendulum calculations before a larger wooden clock. A metronome is one of the few mechanisms that uses a compound pendulum, with a weight above the pivot as well as below it, so he based the rig on one. The result is a charming little working mechanism.
A weight hidden in a steam-boiler-style housing drives the escape wheel through a gravity ratchet and a couple of gears. That gives about two and a half minutes of ticking. Slide the top pendulum weight up to slow it down, or down to speed it up. The weights can also be swapped for heavier or lighter ones. With a scale added it could serve as a real metronome. As published, it's a desk gadget and a lesson in clockwork.
Parts are grouped into three colour-coded ZIP files, with a drawing to show where everything goes. A few parts need multiple copies, and the escapement is two pieces bonded back to back. The designer's own site has more detail.
Who it's for. Clock and mechanism enthusiasts. It's not a beginner print.
What you'll need
Printed parts
- One of each part, except 2 × spacer 3, 4 × pawl and 3 × wedge
- Escapement: 2 parts bonded back to back
Bought parts
- 6 bearings, 2 × 6 × 3 mm
- Steel rod: 1.5 mm for the pendulum, 2 mm for the pivot and 2 gear shafts
- 9.5 mm steel balls for the drive weight
- 12 mm brass rod, or washers (8 g top and 23 g bottom), for the pendulum weights
- A 5 × 5 mm magnet to hold the top weight
- Acetone for solvent bonding
Tools
- Something to cut steel rod
Build overview
Print settings
- ? Material: Solvent-bonded with acetone, which suggests ABS; check the designer's notes
Video
Play video: Metronome Engine running (loads YouTube)
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Photos
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