How I build a mechanical Garmin watch face: a real gear train for a watch with no gears

MY DAY 24
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How I build a mechanical Garmin watch face: a real gear train for a watch with no gears
I build watch faces for Garmin. Some of them show a mechanical
movement: Skeleton, Regulator, Skeleton Bridge and Smoked Crystal. The question
I get about them is whether the wheels are only a picture. The wheels are a
picture. What sits behind them is a calibre I had to solve the way a real one is
solved, and this is why I bother.

1. First, a folder of photographs
Every one of these faces starts as a folder of photographs of real
openworked watches: a Royal Oak Openworked, a Moser Streamliner Tourbillon
Skeleton, a Blancpain Villeret Squelette, and a dozen more. I spend the first
days doing nothing except looking.
I also drop one cheap homage in with them, on purpose, and it turned out to be
the most useful image in the folder. At a glance it has everything a skeleton
should have: bridges, wheels, screws, an open middle. It is also obviously
wrong, and working out why is the whole of this first phase. Its spokes are all
the same width. Its openings are symmetrical. Its bridges carry no bearings, so
the wheels hang in space with nothing to turn on. Every surface has the same
flat brushed texture. It looks like a skeleton drawn by somebody who has only
ever seen one.
The rest of the folder is the opposite. A skeleton is a load-bearing machine
with the metal taken away down to the last safe gram, so what is left is
whatever carries a force, and no spoke is wider than its job. They also all
keep an unbroken ring at the outside. Chaos in the middle, order at the
edge.
Which is what a watch person clocks in half a second, long before they could
say what they clocked. Is the movement complete, and is every part held by
something? That became rule one: everything on the dial is carried by something,
and that something traces back, piece by piece, to the wall of the case.
2. Solving the calibre
Then I design the movement: which wheels exist, how many teeth each one has,
how big it is, where it sits. Barrel, centre wheel, third, fourth, escape wheel,
pallet fork, balance, plus whatever the layout needs to get drive back out to
the hands. This phase decides what the finished dial looks like, and almost none
of it is a drawing decision.
Tooth counts come first and the radii follow. Two wheels can only work
together if their teeth are the same physical size, and if you go the other way
round, picking radii that look nice and deriving counts from them, you get teeth
of different sizes on the same dial. That is what happened on the first pass of
Skeleton: every pinion count had been taken from its radius, the mismatches ran
to sixty percent, and nothing on that dial could have driven anything else.
Positions get solved too. An arbor a fixed distance from two others has one
place it can be, where two circles cross.
On Skeleton Bridge the barrel had to sit further out than its teeth could
reach, so a plain idler goes in between to pass the drive along. It changes no
ratio. Sixteen teeth is the smallest wheel that spans the gap and still meshes
at both ends.
Other positions choose themselves, and that is my favourite thing I learned
doing any of this. The fourth wheel turns once a minute, so the fourth wheel is
the one that can carry a seconds hand, so the small seconds subdial goes
wherever its pivot comes up through the plate. That is the whole reason small
seconds sit where they do on a real watch. Nobody chose the position. The train
chose it.
Underneath all of it is a tension with no free answer. Big wheels spread across
the dial are what make an openworked face worth looking at, meshing pulls every
pair of them tight together instead, and something still has to reach the middle
to drive the hands. Run the train off-centre, as the look wants, and you need a
motion works chain to get back, which only fits if the barrel is small enough to
leave the centre clear.
Regulator began as eleven candidate layouts, drawn flat and cut down to one.
The solved train of Skeleton Bridge. Each circle is a wheel, and each centre is the only point at the right distance from both of its neighbours.
3. Does the train actually run
A drawn movement is a claim. Before anything gets a surface, I test it as a
machine. Every mesh first, for teeth of the same size. Then the rates, from the
barrel out to the balance.
Skeleton beats at 28,800 an hour, eight beats a second, and the escape wheel
advances one tooth per full oscillation, so one tooth every second beat. That
two matters. Sources will happily pair the classic 80/10, 75/10, 70/7 train with
28,800, and that is an 18,000 train. Take one beat instead of two and the watch
runs at double speed.
Skeleton has a tourbillon, so the chain from the barrel to the cage has to
come out at 480 to 1. Then the cage turns once a minute, which is why a
tourbillon runs at sixty seconds in the first place: at that speed it doubles as
the seconds indicator.
Then the physical checks. Two parts at the same height may not overlap, every
arbor needs a bearing above it and below it, and the click and its spring have
to be there, because a mainspring that can unwind backwards is not a watch.
These find things. On one pass the tourbillon cage had no pinion on it, so
the wheel meant to drive it had nothing to push against, and the cage was the
only object on the dial held at neither end. On another the ratchet wheel was
animated at three times barrel speed, when the click holds the ratchet still the
whole time the watch runs. Nobody would have named that in a review. Plenty
would have felt it.
Skeleton before the review of the movement (left), and after its fixes (right).
4. Could a watchmaker assemble it
Running and buildable are different questions, and the second is harder. In a
drawing a wheel turns perfectly well with nothing underneath it. So the render
goes through a pass where it is treated as an engineering drawing, part by part,
and asked whether somebody could put it together at a bench.
The mainplate starts as a full disc reaching the caseband, and the openings
are cut out of it. Build it the other way round, as a ring with a few arms, and
it stops short of the case, and every bridge foot outside that ring is screwed
to nothing. A bridge is a beam, so it wants an anchor at each end; a cock gets
one, out near the edge. A jewel goes where an arbor turns and nowhere else, and
a screw holding nothing gets deleted.
The review of Skeleton at this stage came back with nine fatal faults, and it
was the most useful hour in the project. Nine arbors had a jewel above them and
open air underneath, so a lower plate went in behind the train, on skeletonised
arms, reaching every one. The click spring had been screwed to the barrel, which
turns; it moved onto the fixed bridge above. And the barrel had drifted far
enough over the middle that its tooth roots passed a tenth of a millimetre from
the hands' arbor, so the cannon pinion could never have reached the hands at
all. What comes out the far side is a dial where the eye can follow any part to
a bridge, the bridge to its feet, and the feet to the plate.
Left, bridges cut open at every wheel. Right, continuous beams running over each arbor, with a jewel at every bearing.
5. Materials and finishing
Only now does anything get a surface. The useful way to think about a finish
is what it does in light rather than what it is called, and there are four
behaviours. Black polish is binary: jet black at almost every angle, then
blinding at one. A brushed or striped surface carries a soft bright band across
its grooves, and the band sweeps along the part as the angle changes. Perlage
scintillates, hard little points winking on and off inside a softer patch.
Sandblasted matte simply gets brighter as it turns towards the light. Only the
last of those four falls out of a roughness setting; the other three have to be
built.
Then each face picks from a catalogue. Rhodium plate for the mainplate, a
gilt train, blued screws, and that blue is an oxide film rather than a pigment,
which is why it is more saturated than paint and shifts as you tilt it. The
bridges get anglage, the edge filed back to forty-five degrees and polished to a
mirror, about a fifth of a millimetre wide on the real thing.
There is one more trap, and it cost me a round. Polish on a part a few
across comes out as a dark wire with a bright rim, because on a narrow curve the
dark half of a binary finish is most of what you see. The tourbillon cage taught
me that. With polished arms it read as a peace symbol. Thin parts get satin
instead.
The Regulator mainplate at six times magnification: a brushed face, and the filed edge reading as a single bright line.
6. Lighting the metal

One light, from above, the way a ceiling lights a watch on a wrist. Then the
only question that matters: what on this dial is allowed to be bright?
The rule I keep coming back to is that the biggest object is never the
brightest. Bridges are the largest mass of metal on a skeleton and the least
interesting thing on it, and getting that backwards is most of what makes a
rendered movement look cheap. I got it backwards on the first Regulator
render. The two small gauge pointers were the brightest metal on the whole
dial, and a made-up bounce of light off the wrist lit the movement from
below, so the plate glowed at the bottom, where nothing interesting was.
The answer is not to floodlight the tourbillon. A focal point wins by being
different rather than brighter. On the best photograph in my folder it measures
119.5 against a movement mean of 119.9, which is to say exactly as bright as
everything around it. It pulls the eye with hue and local contrast: a gold rim
against black cage arms, a coloured jewel at the centre, the highest local range
on the dial. That survives being shrunk to a watch screen. A brightness
difference does not.
Where the bright pixels belong is the filed edges, and those are lines rather
than areas, each one changing along its length as the edge turns away from the
light. Anglage drawn as an even outline all the way round is one of the fastest
tells there is.
Behind everything is the space between the parts, never pure black and never
flat. It takes a little colour from the room, and it is brighter at the top than
at the bottom. All nine of my reference photographs agree. One of my faces
painted its void brighter at the bottom for months, on an argument about the
wrist sitting underneath the watch, and the photographs settled it: a worn watch
has a ceiling above it as well.
Colour comes last, and it has one hard limit. A colourway ships as a tint
over a single grey master, the way plating recolours metal without touching its
texture, and a tint can only take light away. So a deep red over bright steel
comes back pale and chalky. Salmon pink is what I write in my notes when I see
it. The way out is to draw the coloured part as its own body underneath and put
the metal's highlight on top.
Regulator before (left) and after (right) the lighting pass, when the light moved to the top and the bridges came down.
7. The night frame

Then the dial gets built a second time, for always-on. This is the dim
version you see with your wrist down, and it cannot be the day dial turned down,
because a screen in that state may only give out roughly a tenth of its normal
light. Dim everything evenly and you get a grey smudge.
So the night frame is drawn from the same parts, on black, with the mainplate
left out entirely. In a dark room a plate that size reads as black anyway, so
losing it costs nothing anyone could see and hands the light budget to the parts
worth seeing. The wheels stay, each turned to its true angle for the time,
dimmed but left at their own colour, so gold still reads as gold. One thing does
come off: the cage stands still overnight, so its seconds pointer would be
frozen, and a frozen pointer goes on telling you the wrong seconds until
morning.
Fenix and the other watches with a reflective screen instead of a glowing one
get the whole thing again. Those panels have 64 colours and four levels of
transparency, and the transparency is the harder of the two. A faint sheen wants
a lot of in-between levels; with four it either vanishes or spreads into a
smear. So the art is refitted to that palette, and the open background goes true
black rather than warm, which is how a reflective screen looks.
8. Getting it onto the watch
The obvious way to ship a movement is to bake it into one flat picture. Small,
instant to paint, and wrong: a wheel baked into the background is frozen
forever, and even the slow wheels go round once an hour, so a watch you glanced
at after lunch would be showing a machine that had not moved since
breakfast.
So every wheel ships as its own sprite, turned to the angle the current time
gives it. The slow ones take a new angle once a minute along with the rest of
the face, which is how a watch
face stays cheap to run. The fast ones take a new angle many times a second,
and only while the movement is running, which is the few seconds after you raise
your wrist.
In a ten-second wake the cage turns sixty degrees and the balance rocks back
and forth four times a second, which is what the real thing does in ten seconds.
The cage steps rather than glides, because the train is held between beats by
the escapement. Everything on a mechanical watch steps like that; the seconds
indication is only the one whose step is big enough to see. How long the
movement runs is yours to set, with ten seconds, five seconds and off.
The faces this produced
Skeleton, sold on the store as
Skeleton Tourbillon, puts the whole machine on show. Eleven wheels, each with
the tooth count of a working calibre, and a flying tourbillon at six, carried
from below with nothing bridging the top of the cage, whose pointer does duty as
the seconds hand. On the
Connect IQ store.
Skeleton on an Instinct Crossover AMOLED, the Garmin with real hands, held up beside Regulator on the screen.
Regulator gives every hand an axis
of its own. Hours on a ring in the upper half, minutes on the long central hand,
seconds in a small dial at the bottom. That layout comes from the reference
clocks on workshop walls, where the hands were kept apart so the long one could
never hide another. On the
Connect IQ store.

Skeleton Bridge stands the
movement on one diagonal beam built like an engineering truss: a rail along the
top, a rail along the bottom, a zigzag of struts between them. The two gauges
beside it are mechanisms in their own right, each with a toothed rack, a pinion
to move it and a marker riding a scale. The middle of the dial stays open, so
the time is easy to read while the machine works around it. On the
Connect IQ store.
Smoked Crystal is the newest. A
tinted sapphire slab lies over the movement, and the wheels show through it at
about a third of the contrast they have on their own, in the colour of the
glass. The date and the weather are read through holes cut clean through the
slab, which leaves them the only two things on the dial at full strength. On the
Connect IQ store.
Smoked Crystal on a fenix 9.
None of this is strictly necessary. I could draw a movement that looks about
right and nobody would check the ratios. I work them out anyway, partly because
the mistakes stay visible even when nobody can name them, and partly because a
train that solves properly puts parts in places I would never have thought to
put them. The fourth wheel decides where the small seconds go. I just draw what
it decides.
Frequently asked questions
Does a skeleton watch face drain the Garmin battery?
Not these ones. At rest the face paints itself once a minute, the same as any well behaved face. The movement only runs after you raise your wrist, and you decide for how long: ten seconds, five seconds, or off. Once it stops, the dial costs what a still picture costs.
Does it work on a MIP Fenix?
Yes. The Fenix Solar models and the other watches with a reflective screen rather than a glowing one get their own version of the art, refitted to the 64 colours and the four levels of transparency those panels have. The wheels, the bridges and the jewels all survive down to the smallest screens. The open background goes true black there instead of warm, which is how a reflective screen looks.
Is the tourbillon real?
It is a drawing, and the drawing is driven by real gearing. The cage turns once a minute, which is what lets it double as the seconds indicator. The balance beats 28,800 an hour, eight beats a second, and the escape wheel advances one tooth every two beats. A watch screen has no moving parts. What is real is the arithmetic behind every angle you see.
Can I turn the animation off?
Yes. Every mechanical face has a setting for how long the movement keeps running after a wrist raise: ten seconds, five seconds, or off. Set it to off and you get the dial and the hands, and nothing spins.
The author builds the My Day 24 watch
face family. Published 2026-09-08.

Made by one developer since 2017 · over 100,000 installs across his Garmin apps
Apps for older Garmin watches (2015–2022): activation & unlock codes
Contact: support@tomasslavicek.cz

The process of building a mechanical watch face, as detailed by the author, involves a rigorous, multi-stage methodology that bridges the gap between aesthetic design and functional mechanical engineering. Initially, the process begins with observational study, gathering photographs of real openworked watches to establish a benchmark for what constitutes genuine mechanical structure. This phase involves critically analyzing the relationship between the visual elements—wheels, bridges, and openings—and the underlying framework, establishing the fundamental principle that every part on the dial must be structurally supported by the movement originating from the case.

The next critical phase is the design of the calibre itself, which determines the appearance of the dial. This involves solving complex gear train mechanics, meticulously determining the existence, size, and placement of every wheel, center wheel, escape wheel, and pallet fork. The author stresses that geometric constraints dictate the design; tooth counts and radii must be physically compatible; deriving dimensions from visual preference without adherence to mechanical ratios results in flawed designs. The positioning of elements, such as subdials, is not arbitrary but emerges from the functional requirements of the train itself, demonstrating that the mechanical train dictates the visual layout, rather than vice versa.

Once the theoretical train layout is established, the design must be rigorously tested as a physical machine. This involves verifying all mesh tolerances, gear ratios, and operational rates to ensure the movement functions correctly. This validation step reveals inherent mechanical contradictions in initial drawings, forcing the designer to make necessary adjustments to ensure functional coherence. This testing confirms that real mechanical constraints, such as the necessity of bearings, the placement of anchors, and the geometry of the escape mechanism, must be incorporated into the design, even when designing purely for visual effect.

The subsequent stage addresses buildability, assessing whether the mathematically sound design can be physically assembled. This involves addressing structural requirements, such as ensuring that components like bridges have necessary support structures, and integrating physical elements like jewels and springs accurately. The author found that theoretical drawings often omitted necessary structural details, necessitating corrections to ensure components possess the required physical anchoring, thereby transforming the design from an engineering sketch into a constructible reality.

Material selection and finishing are treated as integral parts of the design process. Finishes are analyzed based on their visual behavior under light, focusing on optical effects like the scintillation of perlage or the way brushed surfaces reveal texture gradients. The selection of materials, such as rhodium plating and the application of anglage on bridges, must be consistent with the mechanical reality established earlier. The process also addresses optical illusion, noting that certain finishes can create misleading visual effects, and the author advises caution regarding how surface geometry interacts with light.

Lighting is discussed as a final aesthetic layer, emphasizing that visual impact is achieved through local contrast and hue rather than generalized illumination. The principle applied is that the largest physical mass should not necessarily be the brightest element to avoid cheapening the rendering; true visual interest stems from subtle variations in light reflection, such as filed edges, which change dynamically with the angle of incidence.

Finally, the method for presenting the watch face onto a digital screen is addressed, focusing on simulating motion realistically while minimizing power consumption. This involves rendering each wheel as a distinct sprite that updates based on the real time, rather than static baked-in imagery. This simulation must account for mechanical realities, such as the step action of the train, and the ability to set operational modes, allowing the user to choose how long the movement remains active, which effectively handles power management. Ultimately, the process concludes by demonstrating how this intricate mechanical and optical formulation can be translated into distinct visual identities, such as the Skeleton, Regulator, and Smoked Crystal faces, each retaining the logic of a real mechanical movement while adapting to the characteristics of modern display technology.