--- title: "Gear b1 Has 223 Teeth. Forty-Seven Of Them Are Cut Wrong." dek: "A gear metrologist who inspects industrial gearboxes and had never heard of the mechanism measured every surviving tooth on the Saros wheel. Forty-seven sit outside tolerance. The errors are not random; they cluster where a hand stopped." kind: explainer (Explainer) desk: Deep History author: Dr. Perpetua Nkemelu and Dr. Ilse Vantongeren (fictional) published: 2026-08-14T07:00:00Z url: https://theyburied.com/article/antikythera-forty-seven-teeth tags: Antikythera, gears, metrology, tomography, Greece genre: satire status: fiction — nothing in this story happened; every person, source and document is invented --- # Gear b1 Has 223 Teeth. Forty-Seven Of Them Are Cut Wrong. *A gear metrologist who inspects industrial gearboxes and had never heard of the mechanism measured every surviving tooth on the Saros wheel. Forty-seven sit outside tolerance. The errors are not random; they cluster where a hand stopped.* Two hundred and twenty-three teeth. Forty-seven of them are in the wrong place. That is the finding, and it is not a claim about what the Antikythera mechanism was for. The mechanism is what everybody says it is: a geared calculator of astronomical position, made in the second or first century BC, with no known successor for a thousand years. Nothing here disputes any of that. This is a claim about a workshop. ## The file with the label taken off The tomographic volumes of the fragments have been open data since 2006. Anyone may download them, and the people who do are archaeologists, historians of astronomy, and enthusiasts. We gave them to a gear metrologist. Dr. Marit Ojeda-Lindqvist inspects gearboxes for a living — wind turbines, marine reduction drives, the occasional lift. She measures tooth pitch to a hundredth of a degree and writes the reports that decide whether a gearbox comes out of a nacelle. She had not heard of the Antikythera mechanism. We took the label off the file, left the scale bar on, and asked one question: is this drive component within tolerance, and if not, where is it out. It took eleven weeks, because b1 — the large wheel carrying 223 teeth, the Saros count — has 137 teeth still on it and 86 gaps, and every surviving tooth had to be segmented by hand out of a scan made for somebody else's purpose. > **Figure:** Where the forty-seven sit, and what the train does with them — see https://theyburied.com/article/antikythera-forty-seven-teeth ## Forty-seven Of the 137 teeth she could measure, 47 deviate from ideal spacing by more than 0.4 degrees. The worst is out by 1.6. On a modern gear that size, a 0.4-degree pitch error is a scrap decision. She said so before she was told what she was looking at, which is the whole reason we did it in that order. The count on its own is not the interesting part. What she found next is. The errors are not scattered. Plot deviation against tooth number and they sit in three arcs — roughly teeth 14 to 31, 88 to 104, and 171 to 186 — and inside each arc the error runs steadily one way and then jumps back. "That is not wear," she said. "Wear is smooth and it is worst where the load is. This is three places where somebody stopped and started again." ## What a divider does overnight Ferdinand Achterberg-Nwosu cuts clock wheels by hand in a workshop in east London. He has cut something over four hundred. Nothing in the report surprised him. You mark the circle with a divider, he said. You step it round. You file. Then it is dark, or it is Thursday, or a customer comes in, and you put the work down. When you pick it up you re-index off the last tooth you cut — and the last tooth you cut already carries every error you made before it. "Three restarts on a 223-tooth wheel is a fast job," he said. "I would have expected five." > Wear is smooth and it is worst where the load is. This is three places where somebody stopped and started again. > > — Dr. Marit Ojeda-Lindqvist ## Four years The part that matters is downstream. Ojeda-Lindqvist propagated the measured pitch errors through the train as published — she did it the way she would for a gearbox, with no interest in what the pointer pointed at — and the answer is that the Saros pointer accumulates a visible offset in about three years and ten months of continuous turning. Visible means roughly a pointer's width against the engraved scale. Not a catastrophe. Not a broken machine. A machine that has quietly stopped agreeing with the sky. That figure rests on published tooth counts for every wheel below b1, and two of those counts are reconstructions rather than observations. Change either by one tooth and the answer moves by months. It does not move by years. ## The requirement nobody writes on the card If the pointer walks off inside four years, the object cannot have been a thing you set once and then consulted. It had to be reset. By hand. By somebody who independently knew where the moon was, and who did it again every few years, for as long as the mechanism was in service. That is an operating requirement, and it is a requirement for a person, not a part. It says something about who owned this and what they were doing with it that no amount of admiring the gear train will say. ## What this is not It is not evidence of a lost precision we have failed to appreciate. It is not evidence of incompetence either. It is a hand-cut object that drifted, made by people who could see it drifting and evidently did not mind, because the correction cost a minute and they were standing right there. Professor Xanthe Alkiviadis-Wren, whose reply runs at the foot of this page, thinks we have dressed a fifty-year-old observation as a discovery, and that marking an ancient wheel against a modern inspection drawing is a category error that happens to produce a good headline. She is right about the first. On the second this desk still disagrees, and her argument is printed at her length, not ours, so that a reader can decide without taking our word for either. ## Sources (invented) - Dr. Marit Ojeda-Lindqvist, Gear metrologist; inspects wind-turbine and marine reduction gearboxes — Commissioned by this newspaper and paid at her commercial rate; worked from an unlabelled file and was told what the object was only after she filed (March–June 2026) - The published tomographic volumes, Microfocus computed tomography of the fragments, open data since 2006 — Downloaded from the public archive; no permission sought or needed (February 2026) - Ferdinand Achterberg-Nwosu, Horologist; cuts clock wheels by hand with a dividing plate and a file — Interviewed in his workshop over two afternoons, with the report in front of him (June 2026) - Prof. Xanthe Alkiviadis-Wren, Historian of ancient astronomy; has published on the mechanism for twenty-six years — Given the full draft and the measurement table with no deadline (July 2026) ## What we could not confirm - Whether the forty-seven teeth were cut wrong or worn wrong. Our metrologist separates the two on a modern gear by reading the mating face, and two thirds of b1's mating faces are gone. She calls the cutting explanation 'much the stronger of two' and declines to call it established. - Whether the three arcs are three sittings. That is her reading of the clustering, offered as a reading. Nothing in the tomography records a Thursday. - The propagation figure. Three years and ten months assumes the published tooth counts for every wheel downstream of b1, and two of those counts are reconstructions, not observations. If either is wrong by one tooth the figure moves by months. ## Right of reply **Prof. Xanthe Alkiviadis-Wren, historian of ancient astronomy** (Replied on 21 July 2026. Printed in full and unedited, at her length, not ours.): > You have measured something real and then told your readers it is news, and those are two different acts. > > Let me give you the first half honestly, because it is owed. Nobody has published a tooth-by-tooth pitch table for b1. Yours is the first, your metrologist has clearly done careful work, and putting the segmentation masks up so the rest of us can argue with them is more than most laboratories manage. I will use your table. Several of my colleagues will use your table. Thank you for it. > > Now the other half. > > That the teeth are irregular is not a finding. Price wrote it down in 1974. Wright wrote it down at greater length and with a better eye, and the 2006 imaging team said in print that the cutting was hand work with visible variation. Your own third paragraph concedes the mechanism is what we have always said it is, and then the rest of the piece is arranged as though a stranger had walked in and noticed something twenty-six years of us had missed. We had not missed it. We had failed to make it interesting to a newspaper, which is a different failure and one I accept. > > The second objection is the one I would actually like printed. > > Your metrologist marked forty-seven teeth as out of tolerance. Out of whose tolerance? She works to a modern drawing for a modern gearbox that must run at two thousand revolutions a minute under load for twenty years without a person in the room. The Antikythera mechanism is turned by hand, slowly, by someone who is standing there. Its tolerance is not a number on an inspection sheet; it is whatever error the operator was willing to look at before he reached over and corrected it. Marking an ancient object against a specification it was never built to, and then printing the word wrong in your headline, is a category error, and the fact that it produces a good headline is exactly why I mistrust it. > > Where I think you have got somewhere is the last section, and you have buried it. The propagation is the interesting number. If the pointer walks off the scale in under four years, then this object could not have been a thing you set once and consulted. It had to be maintained by a person who independently knew where the moon was. That is a real constraint on who owned it and what they were doing with it, and it is worth more than the forty-seven. > > You have put it eleventh. --- They Buried is a satirical newspaper. Every story, source, document and person in it is invented. It reports from a fictional world in which the conspiracy theories are true, with the method of a real daily.