Why the ST-01 Is CNC Machined from Aluminium
Two Ways to Make a Metal Object
When you make a small metal object, you broadly have two choices: cast it or machine it. Casting pours molten metal into a mould — fast, inexpensive, and suitable for high-volume production. Machining starts with solid stock and removes material until the desired shape remains. Slower, more precise, more expensive per unit.
The ST-01 is machined. Not because machining is inherently superior, but because the requirements of this particular object make it the right approach.
Why Balance Requires Machining
A spinning top that’s even slightly off-balance wobbles. That wobble transfers rotational energy into precession and lateral movement rather than maintaining the spin axis. It shortens the spin and makes the top visually unstable.
Casting introduces porosity — microscopic voids in the metal — and cannot achieve the tight dimensional tolerances that CNC machining can. For a spinning top, tolerances on the order of tenths of a millimetre matter. The mass distribution has to be genuinely symmetric around the spin axis.
CNC machining removes material with cutting tools guided by digital models. The result is consistent across units, within tolerances that casting can't match at this scale.
Why Aluminium
Aluminium was chosen over steel, titanium, or other materials for a combination of reasons:
- Machinability — Aluminium machines cleanly at high speeds, producing sharp edges and smooth surfaces without the tool wear associated with harder metals
- Weight-to-feel ratio — Dense enough to feel substantial, light enough that the object isn’t fatiguing to hold and interact with repeatedly throughout the day
- Anodisability — The anodising process creates a hard, wear-resistant oxide layer directly in the aluminium surface — not a coating applied on top, but a transformation of the surface itself
- Consistency — Aluminium alloy is uniform in composition, which matters for a product where every unit needs to perform identically
What Anodising Adds
Raw aluminium is relatively soft and marks easily. Anodising changes that. The process passes an electrical current through the aluminium in an electrolyte bath, thickening the natural oxide layer to a hardness comparable to some ceramics. The result resists scratches, handles daily contact without degrading, and accepts colour penetration that doesn’t peel or fade under normal use.
The ST-01’s Gunmetal and Matte Black Limited Edition finishes are both anodised — the colour is in the surface, not on it.
The Modular Constraint
The ST-01’s three-component design adds another reason machining is the right choice. The components snap together and apart via magnetic connection. For that snap to be satisfying — precise and positive, not loose or sloppy — the fit between parts has to be consistent across every unit. That requires tight tolerances on mating surfaces. Casting can’t deliver it. Machining can.
The Result
An object that spins true, snaps cleanly, clicks consistently, and holds up to daily handling. The manufacturing method is a means to those ends, not an end in itself.
Read how the design came together: How the ST-01 Was Designed.
The ST-01 is CNC-machined from anodised aluminium. Available in Gunmetal from €49.
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