It’s human nature to look at the technological achievements of the ancients — you know, anything before the 1990s — and marvel at how they were able to achieve precision results in such benighted times. How could anyone create a complicated mechanism without the aid of CNC machining and computer-aided design tools? Clearly, it was aliens.
Or, as [Chris] from Click Spring demonstrates by creating precision nesting thin-wall tubing, it was human beings running the same wetware as what’s running between our ears but with a lot more patience and ingenuity. It’s part of his series of experiments into how the craftsmen of antiquity made complicated devices like the Antikythera mechanism with simple tools. He starts by cleaning up roughly wrought brass rods on his hand-powered lathe, followed by drilling and reaming to create three tubes with incremental precision bores. He then creates matching pistons for each tube, with an almost gas-tight enough fit right off the lathe.
Getting the piston fit to true gas-tight precision came next, by lapping with a jeweler’s rouge made from iron swarf recovered from the bench. Allowed to rust and ground to a paste using a mortar and pestle, the red iron oxide mixed with olive oil made a dandy fine abrasive, perfect for polishing the metal to a high gloss finish. Making the set of tubes concentric required truing up the bores on the lathe, starting with the inner-most tube and adding the next-largest tube once the outer diameter was lapped to spec.
Easy? Not by a long shot! It looks like a tedious job that we suspect was given to the apprentice while the master worked on more interesting chores. But clearly, it was possible to achieve precision challenging today’s most exacting needs with nothing but the simplest tools and plenty of skill.
Very odd – that’s an unlisted video – it’s been up over 2 weeks with only a few hundred views.
Fascinating content – getting that close of a fit with such manual methods is quite incredible
He posted it for Patreon members two weeks ago. May be missed to enable it for main channel.
Every creator has a backlog on YT, and showing these to Patreons is a great way to reward your fans and have a private viewing of your next project. Maybe catch an issue or two. I believe the Patreon shouldn’t have sent it in, and Hackaday should have caught it as well. It wouldn’t have hurt a bit to wait with posting the article until the video was released to the public.
It’s not a reward on the fans, since they would have first access anyways. It’s a penalty on everyone else.
“Paid first access” is just another way to extract what’s known as “economic rent”. It’s money you earn by not doing something of value, exactly because you aren’t doing it.
I.e. the thing already exists, and it’s technically been paid for already by the subscribers who wanted to pay for it, but you’re placing an arbitrary penalty of time on non-subscribers to entice them to become subscribers, to earn that much more money. That sort of behavior is considered “rent-seeking”, or, “growing one’s existing wealth by manipulating the social or political environment without creating new wealth”.
Unless of course the fans do derive value out of being jerks to everyone else – kinda like people who buy exclusive products just to brag and display social status. Then holding the stuff back would be a reward on the patrons.
You never know.
The skill it takes not only to do this with such limited tools, but to make it look easy is absolutely incredible.
Since I saw a sole stonemason patiently polishing a stone brick in Bolivia, I know that the ancients were able to make all such wonders. For today’s average people it is not understandable like the evolution theory 150 years ago. And this manual lathe, wov:)
Not to mention that he apparently films all this in a shop not much bigger than a closet.
In ancient Greece, they had to work in closets. Big rooms hadn’t been invented yet. This is part of his commitment to historical accuracy.
Greeks never came out of the closet. As the old saying goes, they invented love, but it was the Romans who finally introduced it to women.
The amount of work necessary is often overestimated.
I have joined into the organisation of the rebuilding of a “Hunebed” (Dolmen) with stones up to 25 tonnes. We moved a 6 tonne stone on a sled, rolling on poles, over a very sandy road, just pulled by 20 elementary-school children, with ease, and over a distance of more than a kilometre in one morning. In fact, most of the brunt was on the grown-ups who had to move the poles from back to front.
Also, I recently learnt that the “Dom” church of Utrecht (which took more than 2,5 centuries to construct) usually had a construction crew of less than 20 people, basically a one or two stoneworkers with apprentices, a carpenter with apprentices and a few people moving stuff. So it took long, but there wasn’t enormous manpower involved.
I appreciate the historical accuracy of conscripting small childs for that build.
With a few hundred apprentices/slaves commandeered by the local royalty, working with a couple dozen lathes, precision items of all sorts—pulleys, balls, bushings, tapers—could be constructed in a relatively short time. And with a lathe at hand a primitive milling machine for accurate flat surfaces could be devised. Gears might be a bit challenging; machining a disk would be trivial but cutting some arbitrary number of accurate teeth…not so much.
I built the Gingery lathe many years ago and am familiar with the amount of hand work required for precision.
oh, clickspring has several videos on the general subject of gearwheels, including Antikythera-style ones.
short version: triangular teeth are a tedious and labor-intensive task involving hand filing, but quite doable. modern gearwheels don’t use triangular teeth, and for good reason, but making the modern styles very likely requires a modern lathe.
Not all that modern, but certainly more complex than what was available in this case.
Clickspring’s precision and delightful quality of the final products makes me feel inadequate.
It’s not just his workshop craftsmanship that makes everyone feel inadequate. The quality of his videos is superb, and they feel professionally produced. They’d feel right at home on the old Discovery channel before they abandoned their educational orientation.
Chris can address this but if I remember correctly I think his day job is in the video production field. There is something about the color balance or lighting of his videos that is really captivating (not to mention the fantastic content),
I guess I need to watch the video, but I can’t figure out how he made the fit of one tube in another tighter by abrading away material from either one. If the hole was undersized, or the inner one oversized, then I could see it, but if they’re already a sliding fit, they could only get looser if material is removed from either one. What am I missing?
Maybe watch the video, lol.
It didn’t explain it. He put one tube inside another and then twisted it with the lapping compound in between – but that should have resulted in a looser fit, not a tighter fit. Something is missing here.
I was also wondering about this. I was thinking maybe the material is being moved from the high spots to the low spots? But I don’t really know a lot about how lapping works.
He mentions that the fit before lapping was light interference fit — this would mean the hole was very slightly smaller than the inner tube, and a fair amount of force would have been needed to get one tube inside the other. This wasn’t really apparent on camera though — I imagine he could feel it though.
The sliding fit he mentioned would have been the end goal of the lapping. It would have been gas tight initially — the air piston demonstration after lapping is showing that movement is now free, while still being a decent pneumatic fit.
If it was an interference fit, then you couldn’t get the tubes inside one another to lap them, because the lapping compound wouldn’t fit in between. It still doesn’t make any sense.
What’s more likely is that there were two or more sets of tubes made, and they were mixed and matched until pairs were found that could be lapped smaller or looser to fit each other perfectly, using the loosely fitting remaining tubes as sacrificial lapping tools.
Or, the third alternative is that the video is a cheat: the pneumatic action is accomplished with oil in between the parts.
I see what you’re saying. It’s not addressed in the video, but if it was me, maybe only lap the parts when the inner part is cool, and the outer part is hot.
The method is very similar to what Stephan Gotteswinter uses. First ream a hole, then put it over a mandrell, and then grind the outside concentric with the already finished hole, as seen in:
https://www.youtube.com/watch?v=_rjjZfnK-m4
Main difference is that Stephan does it to earn sandwiches by selling the product, and not for researching archeological methods. But overall, the difference is quite small.
I am one of his Patrons. When he dropped the video to us about two weeks ago, I wrote to Clickspring and asked him. He dropped it publicly 25 April 2025 about 1800 UTC.
He told me that this is exactly how he did it ie made the hole and then turned the outer walls to be concentric
Wait how does he achieve a gas tight seal by starting with something that has enough of a gap between the two surfaces that he can fit the jewelers rouge in between them. Then using that to grind out more material and somehow making the fit TIGHTER? I’m so confused.
He mentions it’s a light interference fit to start with. The metal is being elastically deformed when one tube is inserted in the other. Also the particles are harder than the metal, so they can embed in the surface and elastically deform it. Likely it was gas tight to start with, but certainly not free moving.
That sliding fit he’s showing in the end implies some clearance between the parts, probably on the order of 50 microns or so. This is enough to produce the gas piston effect shown when the parts are in motion.
That size is likely quite a bit larger than the rust particles in question.
The end result of the lapping was to eliminate most of the sliding friction, but precisely enough that the seal was maintained.
A “light interference fit” would squeeze the lapping compound out when you force the tubes into one another, and even a light interference fit would bind them so you can’t turn them, so lapping wouldn’t be possible.
What’s more likely is that they had a “transition” fit where the inner tube is technically only slightly smaller, but you get some high and low spots that interfere. If you add the lapping compound and start working the parts together, it evens out and you get a pretty tight clearance fit. Possibly even a pneumatic fit.
That would make sense, but he shows the tubes fitting into one another first and then being lapped. That requires that there is already a fairly loose clearance fit because the high and low spots left by drilling and turning pass each other just fine. Lapping it even makes the clearance even bigger. That may still be fine for a bearing, but would not make a pneumatic fit.
A drop of oil or water however would seal it right up, making the appearance of a pneumatic fit even if it wasn’t.
Next on “Wisdom of the Ancients”: What is this “rabbit ears” antenna? Why were they so obsessed with rabbits? Was it a religious symbol?
These people are building one-off precision sets. Not manufacturing hundreds of items with the tolerances of ‘all fit’.
The same processes as were used in crafting early firearms. Each item was a single unique assembly built by a single artisan. They all worked but were not interchangeable with regard to their respective component parts.
Stop thinking in terms of modern geometric dimensions and tolerances and see it as the ART of making!
Manufacture; built by hand!
From the land of bear skins and stone knives