Stainless steel 1.4301 · Designed in Germany · First run in preparation
13 Notes
Notes on steel, tolerance and the things that had to be decided.
Field Note 01 / 13
1.4301 does not resist corrosion because it is dense. It resists because the chromium in it reacts with oxygen and forms a film of chromium oxide between one and five nanometres thick — thousands of times thinner than a sheet of paper. Scratch through it and it reforms within seconds, as long as there is air. The steel repairs its own surface. The brushed finish is bare steel.
Field Note 02 / 13
Under EN 10027-2 every European steel carries a number. The leading 1 means steel. The 43 places it among the chromium-nickel stainless grades. The 01 identifies this exact composition. AISI 304 is the American name for the same material. We print the number rather than a word like "premium steel", because a number can be checked and a word cannot.
Field Note 03 / 13
316 adds two to three percent molybdenum, which buys resistance to chlorides: sea water, coastal air, road salt. For an object carried in a pocket it buys nothing but cost. 304 is the grade used for cutlery, sinks and food equipment. We chose the one that matches the job.
Field Note 04 / 13
A human hair measures roughly 0,07 mm across. The mating surfaces of this tin are held to ±0,05 mm, so the permitted error is smaller than a single hair. Every other dimension follows ISO 2768-m, the general tolerance class. A drawing that names no tolerance class is not a finished drawing.
Field Note 05 / 13
It is French: détente, from détendre, to release. The detent was the catch that let a clock's striking train go at the right moment. The same word later gave us the political détente. The twenty-four detents in the carrier ring do what the clockmakers needed — hold a thing exactly where it belongs, and let it go when asked.
Field Note 06 / 13
360 divided by 24 is 15. The same division as the world's time zones, and twice the hour marks on a clock face. Fifteen degrees is fine enough that a divider lands close to wherever you meant it, and coarse enough that no two positions can be confused.
Field Note 07 / 13
Detents exist because fingers judge a click better than eyes judge a position. A camera's aperture ring, a dive watch bezel, an oven knob, a bicycle gear shifter — all the same idea. The carrier ring is built on it.
Field Note 08 / 13
Stainless steel moves heat roughly eighty times faster than polypropylene. A steel object that feels cold is not colder than the plastic beside it — it is pulling warmth out of your hand more quickly. That sensation is the material telling the truth about what it is.
Field Note 09 / 13
A brushed finish is a directional grain of very fine scratches. It scatters light along one axis, and because the surface is already textured, new marks and fingerprints have nothing to stand out against. A mirror polish shows every one of them. This object is meant to be carried, not displayed.
Field Note 10 / 13
0,12 mm. Ordinary office paper is about 0,10 mm thick. The wordmark is not printed and not filled — it is removed material. It is part of the steel itself.
Field Note 11 / 13
In 1896 Carl Edvard Johansson, an armourer inspector at the rifle factory in Eskilstuna, built the first combination set of gauge blocks: steel blocks that could be stacked to thousands of different lengths. He finished them at home, on his wife's sewing machine converted into a grinding machine. They were so flat that two would cling together when twisted, held by nothing but contact. Interchangeable manufacturing — the reason any part fits any other part — starts there.
Field Note 12 / 13
It was defined as one ten-millionth of the distance from the equator to the North Pole. Since 1983 it has been the distance light travels in 1/299 792 458 of a second. Every number on our drawing — 74,0 and 26,0 and 18,2 and 1,1 — is a fraction of that.
Field Note 13 / 13
Round was not a styling decision. For a given perimeter a circle encloses more area than any other shape, and a round lid cannot be put on crooked. The price of a circle is that nothing inside it has a fixed place. That is precisely the problem the carrier ring exists to solve.
