Did Achim Leistner's hand-polishing ('atomic feeling') actually outperform machine methods on the Avogadro spheres, and is the account corroborated beyond the Powerhouse Museum caption?

metrologycraftsmanshiptactile-cognitionverificationavogadro-constant

claim-leistner-atomic-feeling-hand-polished-avogadro-spheres carries an [unverified-historical] flag. The biographical spine (Leistner, Zeiss-Jena training in 1953, emigration to Australia in 1957, hand-polishing at CSIRO) is uncontested and fine at Tier 3–4. The problem is the surprising, load-bearing element: that the manual "atomic feeling" technique "proved superior to purely machine-based methods" at the nanometer scale. That is a craft-superiority claim resting on a single Tier-3 source — the Powerhouse Museum's own object record — which is below the sourcing floor for a surprising claim that is the emotional core of the note.

Why it matters

This is the hinge the whole capture turns on, and its bridge into the vault's tactile-cognition cluster (claim-saunderson-palpable-arithmetic-tactile-calculating-device, claim-blind-mathematicians-independently-reinvented-private-notation) is only as strong as the "hands beat machines" claim. Until it clears the floor, the note stays seedling and cannot anchor a draft on touch-exceeding-instrumentation.

What would answer it

• CSIRO's own account (technical report, precision-optics group history, or a named CSIRO scientist's statement) of how the final sphere figuring was done and what role manual technique versus instrumented/machine polishing played.
• A metrology or optics-journal write-up (Tier 1–2 — e.g. Metrologia, IOP, or a peer-reviewed Avogadro Project paper) describing the sphere-figuring process and whether hand-lapping outperformed machine methods, and in what respect.
• Any primary interview with or obituary of Leistner from a named journalist or scientific society (not a museum caption) attesting to the "atomic feeling" nickname and the superiority claim.

Candidate next moves

Start from the Avogadro Project / International Avogadro Coordination publication list and search Metrologia for the silicon-sphere roundness/topography papers, which would name the polishing method. Cross-check the Wikipedia article on Achim Leistner (cited in the capture's hop chain but Tier 4) for its own references and chase those to primary.

Progress — 2026-08-13

Followed the Wikipedia footnote chain to primary. Result is mixed rather than a clean answer:

• The account itself (nickname, general narrative) is now corroborated by two more independent named-journalist sources — Wired (Jonathon Keats, 2011) and New Scientist (Devin Powell, 2008) — beyond the Powerhouse Museum. See claim-leistner-atomic-feeling-corroborated-beyond-powerhouse-museum. That half of this question is answered: yes, corroborated beyond the museum caption.
• The specific "beats machines" superiority claim is echoed by Wired independently, but still has no Tier 1–2 primary — see claim-leistner-hand-beats-machines-claim-lacks-tier1-primary.
• A Tier-1 Metrologia paper (Azuma et al. 2015, via arXiv:1512.05642) shows a 2013–2014 PTB repolish of the actual AVO28-S5/S8 spheres produced measurably lower peak-to-valley roundness deviation than "the initial spherical state produced by the Australian polishing" — i.e. a later, different process beat Leistner's original hand-finish on the one quantitative metric available. See claim-ptb-repolish-out-rounded-leistners-original-avogadro-spheres. Whether that PTB process was itself hand-guided or machine-automated is unread (Meeß et al. 2014, not fetched this session), so this doesn't settle "hand vs. machine" cleanly either — it just shows Leistner's finish wasn't the permanent last word.
• Leistner's own technical papers (Leistner & Zosi 1987, Applied Optics; Leistner & Giardini 1991/92, Metrologia) — the primary account in his own words — remain paywalled and unread. This is still the strongest lead for actually resolving the superiority claim and is why the question stays open rather than closing.

Left open, not answered: the corroboration sub-question is settled, but the technical superiority claim this question turns on is still unresolved at the sourcing floor, and now sits alongside a Tier-1 complication rather than a clean confirmation.