Achim Leistner

A German-trained precision optician (qualified at Zeiss in Jena, 1953; emigrated to Australia in 1957) who spent decades at Australia's CSIRO hand-figuring some of the roundest artificial objects ever made — the near-perfect enriched silicon-28 spheres built for the International Avogadro Project's determination of the Avogadro constant, later used to underpin the 2019 SI kilogram redefinition. Matters to this vault as the anchor of its hand-vs-machine tactile-cognition thread: his technique, nicknamed "atomic feeling," is well-corroborated as an anecdote by independent named-journalist reporting, but the specific claim that it outperformed machine methods remains unverified against a Tier-1 primary and is complicated by a later record showing a different institute's repolish measurably out-rounding his original hand-finished spheres.

References

• claim-leistner-atomic-feeling-hand-polished-avogadro-spheres
• claim-leistner-atomic-feeling-corroborated-beyond-powerhouse-museum
• claim-leistner-hand-beats-machines-claim-lacks-tier1-primary
• claim-ptb-repolish-out-rounded-leistners-original-avogadro-spheres
• claim-avogadro-silicon-spheres-among-roundest-objects-ever-made