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How machines learned precision

https://glinscott.github.io/how-machines-learned-precision/ (glinscott.github.io)

218 points | 2d ago | Discuss on Hacker News | Back to Radar

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glinscott (author) 2d ago on HN
Author here. This is a sequel to my beam engine article: https://glinscott.github.io/beam-engine/.

I started digging into Watt's challenges getting an accurate cylinder bore for his pistons, and it spiraled out from there :).

The article covers some of the key techniques developed during the industrial revolution to measure and make incredibly precise parts. There are a lot of animations and interactive figures to explore how it works.

ahazred8ta 2d ago on HN
Armchair metrologist here. Did metalworkers back then use 16ths, or 12ths and 24ths? I'm familiar with the use of 1/12th lines ''' and multiples of 1/144th points ''''.
glinscott (author) 2d ago on HN
Good question! From my reading, English engineering shops like these used 1/8ths and 1/16ths. Whitworth did push for "decimal inches" (1/10, 1/100, etc). It seems like the 1/12th and 1/144th were more common in watchmaking and optics.
ahazred8ta 17h ago on HN
Ditto the makers of scientific instruments, and the manufacturers of moveable type. The printer's ligne was 1/6 of a continental inch, and the typographic pointe was 1/12 of a ligne.
ahazred8ta 2d ago on HN
Interesting that many of the early steam mills used a steam engine to pump water into a water tower, which then drove a conventional water wheel to power the millworks.
glinscott (author) 25h ago on HN
Yes, until they were able to get smooth rotation out of the engines, the water wheel was a much smoother source of power. Especially for looms and weaving machines, stable, smooth power was critical. "Power in the Industrial Revolution" by Richard L Hills is a deep exploration of the history there :).
HPsquared 25h ago on HN
Reliable too, I suppose.
glinscott (author) 20h ago on HN
The rivers and streams actually turned into a battleground! This is an excerpt from my beam engine article:

The fight for water Richard Arkwright's water-powered mill at Cromford opened in 1771, and the factory system that followed created fierce demand for the best river sites. Water-powered mills were also dependent on the weather: a dry season could shut down the factory.

Steam pumping engines offered a solution. An engine lifted the water that had passed beneath the wheel back up the hill, allowing the same water to fall through the wheel again. This kept the smooth turn of the water wheel, but wasted coal moving the water. Watt sold sixteen to twenty horsepower pumping engines to deliver ten horsepower to the machines.

Watt's double-acting engine, beam, crank and flywheel let the engine directly turn the line shaft. This met a huge demand from mill owners who wanted to build near workers and materials rather than around a particular stretch of river.11 One problem remained, though: every time a machine was turned on or off, the load on the engine changed.

cowlevel 21h ago on HN
Early electric mills replaced their big centralised steam engine with a big centralised electric motor. And the first web browser was a program running within a non-web-based operating system.
m4rtink 20h ago on HN
Yeah, saw one house that was this kind of "electric mill" originally - electric motors were expensive so it made perfect sense to just have one big motor and transfer the power using leather transmission belts. Not to mention all the machines needing power at that point expecting it to come from a belt drive.

The big motor and most of the machinery was long gone but you could still see where the belts went through duento various holes and cutouts, now usually closed by wooden blanks.

HPsquared 10h ago on HN
That reminds of those old belt-driven ceiling fan systems. You'd have a single motor and a system of belts arranged on the ceiling to drive an array of ceiling fans. I think that'd be a super charming feature to bring back in bars and cafés.
RivieraKid 25h ago on HN
How was AI used when writing the article? Not implying anything, I haven't started reading it (yet).
glinscott (author) 25h ago on HN
Certainly a fair question!

The text was hand written, but reviewed by AI and light edits were made. The CAD models that drive a lot of the animations were either sourced or built based on pictures of historical machines. As called out in the credits, the interactive figures were built by myself and Claude Fable 5 (mostly - a bit of Opus 5.5 in there now).

The article itself was built over about 4 months.

dekhn 24h ago on HN
What CAD do you use for the models, and does it have a CAM simulator (for example, you might actually be able to simulate the tread cutting in Fusion 360 CAM's simulator.
glinscott (author) 22h ago on HN
I used onshape, but just the basics :). The thread cutting was done just as an animation.
YuechenLi 23h ago on HN
Hey, so a bit of self-promotion for some free software I built that you may be interested in.

https://github.com/yuechen-li-dev/Aetheris/

It's a code-first CAD kernel/toolkit specifically to help LLMs with CAD stuff, it's currently AI usable but not very human usable yet since I'm working on the editor UI. Get your Claude to clone it and give it a try and see if it's easier than your current workflow.

I built two 3D mechanical demos with it a couple of weeks ago that you can check out as well. https://aetheris-difference-engine-showcase.yuechenli.worker... https://aetheris-editable-v8.yuechenli.workers.dev/

HPsquared 25h ago on HN
Very cool! Though my ChemEng degree obligates me to say that the animation in the "steam" section should really show boiling all the time if the pressure gauge is indeed showing the pressure in the container. Though in reality you'd never heat water at below atmospheric pressure in a real engine, if you did it would be boiling at any temperature at or above the triple point, and below the critical point, so long as there is no air in there.
Animats 25h ago on HN
Piston rings were really bad in the early days.

Remember, this was all iron, not steel. The mass production of steel didn't get going until the 1880s. It's amazing that railroads predate steel.

WillAdams 23h ago on HN
Early iron rails wore out and had to be replaced after a given usage (measured in years on a heavily traveled section) --- this was a big part of the need for the Bessemer process to be developed.
xenadu02 19h ago on HN
It was worse than that. No one really understood or had a handle on the production process. During this time period the notion of iron being a chemical element was a recent discovery.

So what you got may have been called cast iron but what it actually was might be pig iron, gray cast iron, ductile iron, and even a bit of steel and possibly carbides mixed in. Properties varied - sometimes by a lot.

If you know even a bit about metals then when you hear "cast iron piston ring" you imagine that ring to have certain properties that match a specific type of cast iron. But in those days every single ring might vary significantly entirely due to the ore load the foundry happened to get, how they melted/cast it, how it was cooled, etc.

_doctor_love 24h ago on HN
Have you read "The Perfectionists" by Simon Winchester? Great book if you're into this stuff!
glinscott (author) 23h ago on HN
Yes, a wonderful book :).
gmac 12h ago on HN
Note: the same book is titled "Exactly" in some markets (including the UK).
gblargg 24h ago on HN
These could really use a way to really pause everything so one can read the text without distracting animations.
anitil 20h ago on HN
Is there any chance you'd add an RSS feed to your blog? Unless I missed one?
imtringued 13h ago on HN
You should consider making a blog post about steel and wrought iron production.

The wrought iron mills had enormous powered hammers. https://en.wikipedia.org/wiki/Catalan_forge

https://en.wikipedia.org/wiki/Finery_forge

Onavo 3h ago on HN
Given that the most efficient design right now is a turbine, how difficult would it be to machine one in the 1800s in an alternative history world?
Joker_vD 25h ago on HN
> After repeated copying and correction, Maudslay made a master screw five feet long and two inches across, with fifty threads to the inch and a foot-long nut that engaged six hundred of them at once.

That's the stuff I like to read about the historical endeavors. A fifty-threads nut doesn't average the distance between the grooves quite accurately enough? Then let's make a nut with six-hundred threads on it, and so what if it's foot long.

anitil 22h ago on HN
I actually didn't understand that paragraph. Is it saying that instead of averaging between two screws it instead averaged across 600? Edit: Or that the nut had 600 threads?
glinscott (author) 22h ago on HN
Sorry it wasn't clear - the nut had 600 threads.
anitil 21h ago on HN
Ah amazing thankyou! I'm really enjoying it and it has cleared up a lot of things I'd vaguely heard about but never fully understood
HPsquared 25h ago on HN
I've sometimes thought of making a YouTube series where the foundations of precision are created as increasingly precise artifacts, building on each other and following the history. Something like the "Primitive Technology" channel but for machine tools.
nayuki 24h ago on HN
Some of your ideas have been covered before, e.g. https://www.youtube.com/watch?v=gNRnrn5DE58 , https://www.youtube.com/@machinethinking/videos . But I would love to see your take on the topic and see a more complete story.
peterldowns 8h ago on HN
Thank you for these!
pcthrowaway 20h ago on HN
You might enjoy the anime Dr. Stone.

It follows a somewhat similar premise, though it's obviously a work of fiction, and animated. Still, the progression of rebuilding all of the world's technology from scratch is very detailed and impressive.

jeeshan 24h ago on HN
how did you make these videos? ive struggled to understand mechanical systems from static figures and these are super helpful
glinscott (author) 24h ago on HN
Awesome, glad they helped :).

It's a mixture of techniques. Using fully rigged CAD models is a huge help, it ensure physically realistic motions. Then, I built a custom exporter / renderer to render them realistically in CAD style.

For a lot of the animations, I first develop storyboards to cover the main beats, and decide on what would be interactive or not. Then a lot of iteration with Fable (and Opus 5.5 now!) on how to show things clearly. A lot of time is spent trying to show the key ideas visually. Eg. in the bench micrometer adding an overlay with the size of the micrometer closing over the part, as well as showing the screw spinning was a big improvement in "readability".

nayuki 24h ago on HN
Good work! Your style of animated articles reminds me of the work of Bartosz Ciechanowski: https://ciechanow.ski/archives/ , https://news.ycombinator.com/from?site=ciechanow.ski
glinscott (author) 24h ago on HN
Oh my, I forgot to add him into the credits for this one! The Beam Engine article has this: "Thanks to Bartosz Ciechanowski, whose exceptionally well written and designed articles inspired this one."
qchris 23h ago on HN
Anyone interested in this might also enjoy the book The Perfectionists: How Precision Engineers Created The Modern World, by Simon Winchester. I read it a few years ago, and thought it was a really interesting journey through bootstrapping precision and how that fundamentally changed our relationship to certain types of things, particularly related to mass production of "good enough".
rossng 22h ago on HN
I was rather disappointed by this book. Felt that it spent a lot of time waffling about irrelevant detail[1] and failed to really present a coherent narrative about how precision engineering was developed.

Conversely I rather enjoyed The Origins of Efficiency by Brian Potter, which tackles the topic of how manufacturing became scaled and efficient. I would love to read a similar book on precision.

[1] particularly the endless guff about Rolls Royce, which I felt really detracted from the book

YZF 21h ago on HN
glinscott (author) 20h ago on HN
Oh yes, this is the PhD version :).
ghm2180 23h ago on HN
Thank you for making this. My dad(now retired) owned a machine tool manufacturing space in the 70s and 80s in a small town in north india. After foreign CNC machines left no demand for manual/semi automatic ones in the country, he switched over to a foundry to manufacture cast iron parts in a blast cupola furnace and later a rotary furnace(better for smaller on demand work). But he kept the lathe around along with an employee to finish the parts. And your animation brings back a lot of memories for me. I learned to operate the lathe and had all manners of fun. It is kind of like yak shaving. Your clothes turn black but you just love the mechanical back and forth of it. He made pulleys, Truck engine parts, housing for water motors(fun fact municipal water is scarce and not of adequate pressurized in homes, farms, factories etc so these are ubiquitous) etc.

I sent this to my dad. I am sure he will enjoy reading this.

glinscott (author) 23h ago on HN
You are welcome! Thank you for the background, I'm glad it brought back some pleasant memories.
WillAdams 23h ago on HN
This sort of thing makes me wonder what the successor is to the Gingery Books now that they're going away:

https://gingerybookstore.com/

Chris Borges has done some pretty cool little machines using 3D printed forms filled with concrete:

https://www.printables.com/@ChrisBorge

and of course there are more CNC router designs than one can shake a stick at (ob. discl., I work for a company which makes one)

cowlevel 21h ago on HN
You could download the books.
WillAdams 20h ago on HN
I own the leatherbound hardcover which I purchased when nostalgia for the original Vol. 2 _The Metal Lathe (Build Your Own Metal Working Shop From Scrap_ got to me.

The thing is, it was written for a different time, and I believe that it should be possible to do a more capable design which is more readily sourced/fabricated given the changes in what is available at a hardware store these days.

Or, maybe I'll just buy a casting kit and make a Shaper....

anitil 23h ago on HN
What really surprises me about these precision machines is how recent all of these inventions are, only a couple hundred years
LoganDark 23h ago on HN
The pace of technological progress is incredible these days. It's amazing and also scary and unpredictable. Like, will we understand ME/CFS within my lifetime? The rate of achievement is so insane that it very well may be possible, but we just won't know unless it happens (or I die first).

The dystopian surveillance panopticon is progressing nicely, though, and new generations are growing up without any notion that privacy was ever possible in the first place. I had a harsh reality check when I met someone online who didn't even know old Reddit existed and then even disliked it. It made me so sad.

Also, there's a meme floating around that technological progress came to a screeching halt during the "Christian dark ages", so maybe it's just that we're finally getting back up to how we were before then! (Lmao)

here_to_learn 22h ago on HN
I love these kinds of articles, of how we bootstrapped technology.

I would welcome suggestions for books that describe the advance of technology from early times.

Im a distractible reader so I prefer books that are a bit more personal and story telling rather than dry.

Thanks!

Hikikomori 22h ago on HN
The Perfectionists: How Precision Engineers Created the Modern World

Maybe this one? Haven't read it but I think a machinist youtuber recommended it.

here_to_learn 21h ago on HN
That is an awesome suggestion, thank you! I found it on ebay and am looking forward to reading it.
peterldowns 22h ago on HN
Industrial history and the history of precision manufacturing is extremely exciting to me. This is an excellent overview and the animations — while not quite as smooth as https://ciechanow.ski/ — add to the experience.

If you liked this blog post, you may enjoy the book “English and American Tool Builders" by Joseph Wickham Roe.

hexapus 22h ago on HN
This is very neat. My engineering nerd friend was immediately turned off by the seeming conflation of "precision" and "accuracy" in the title/subtitle though. As this article seems aimed at laypeople, clearing up the difference upfront by defining them might be helpful, as they are not interchangeable.
glinscott (author) 22h ago on HN
Ah, heh. That's a very fair point. To be honest, I struggled with the title and subtitle, because most of my ideas had "Precision" in them, and it sounded like I was repeating myself.

I had thought about talking more deeply about the difference between them, but the article was already getting too long! It's certainly worth a footnote though. Revision upcoming :).

mitthrowaway2 22h ago on HN
> Maudslay also devised an ingenious method that used two imperfect screws to guide the tool cutting a third. Equal gears turned both guide screws at the same speed. A bar joined their two nuts, with the tool fixed at its midpoint, so the tool's position was the average of the two nut positions. Where one guide ran ahead and the other lagged, their errors partly cancelled. Each guide contributed only half its error to the new screw.

Actually, this invention is Leonardo Da Vinci's! Here's what his screw-copying machine looked like.

https://cdn.britannica.com/39/60539-050-BCB3019D/machine-Leo...

https://media.sciencephoto.com/image/c0661830/800wm/C0661830...

The screws can also be taken out and flipped end-over-end, averaging out the errors even further.

glinscott (author) 22h ago on HN
Oh wow, that's awesome! Thank you, I will correct the article.
UltraSane 21h ago on HN
This page deserves some kind of award for excellence in pedagogical design.
pillars 20h ago on HN
Great Work! I want to share some great resources related to Precision Engineering:

[1] Origins of Precision

https://www.youtube.com/watch?v=gNRnrn5DE58

[2] The books that taught me precision

https://www.youtube.com/watch?v=FM9X_gjnleY

[3] 2.75 FUNdaMENTALs of Design - Alexander H.Slocum

https://www.youtube.com/watch?v=wgMq7yha9wU&list=PLksE8LDXGX...

[4] Building the most accurate DIY CNC lathe in the world

https://www.youtube.com/watch?v=vEr2CJruwEM

[5] Design Principles for Precision Mechatronics

https://www.dspe.nl/knowledge/dppm-cases/

[6] Tutorials in Optomechanics

https://wp.optics.arizona.edu/optomech/tutorials-in-optomech...

[7] American Society of Precision Engineering - Recommended Readings

https://aspe.net/resources/recommended-readings/

[8] What books should a precision engineer read?

https://precisionmindsetllc.com/recommended-readings.html

Precision engineering is the biggest rabbit hole,an endless supply of interesting stories and artifacts.

djriley 19h ago on HN
Something I feel was sort of left out here was precision grinding which began to come in to play right around the same time period this article focuses on. Grinding is what really allowed the industrial revolution to explode. Tight tolerances and good surface finishes allowed things to run faster and more efficiently. Automation and repeatability lead to high production of tooling and products that eventually lead to mass production.
adm4 19h ago on HN
Jo Blocks https://en.wikipedia.org/wiki/Gauge_block
xenadu02 18h ago on HN
An amazing page, thanks for posting it!

I got a lathe a few years ago as a hobby and really enjoy making something with high precision by hand with no computer or LLMs involved. Of course I make everything nice because I make it twice (due to my own errors).

The history of lathes always interested me - especially how some features are so standard we think of them as integral to all lathes but that was not the case! Most lathes in use today are technically screw-cutting engine lathes.

Every increase in precision in your tools leads to even greater precision in what you can make if you are careful and clever. In that sense every machinist has to start with a lathe because a lathe is the most versatile machine and is capable of making replacement parts to improve itself. Even a relatively crude home-made lathe can be enough to machine better parts to install onto the lathe to keep improving it. Even my little import hobby lathe (PM-1030V) can make parts to a tenths precision (tenths = 10,000th of an inch or .00254mm) with some care and it is not what you would call a rigid and accurate machine.

You might wonder how humans turning a wheel were able to cut metal but in those days they didn't have HSS let alone carbide tools so they had to use whatever would hold an edge (carbon steel for a long time). That meant much much slower turning speeds, much smaller depth of cut, and much more frequent sharpening. I believe it was around 1869 Robert Mushet invented Mushet steel and later Maunsel White and Taylor worked with Bethlehem Steel Co to invent the first modern "tool steel" alloy. They are of course called High Speed Steel because they allow you to turn the work at high speed when cutting. Something of an ironic name in the modern world as carbides are far higher speed than HSS.

Manual machining has declined thanks to CNC but there are still plenty of jobs where manual machining is faster and cheaper than setting up a CNC program. Of course those of us doing it as hobby aren't bothered by such things.

laybak 17h ago on HN
excellent interactive education content. this reminded me of the steam engine exhibits at the science museum in London
userbinator 16h ago on HN
A belt-driven New Haven planer of the 1890s

There is a multi-year video series on YouTube where one of these is restored: https://www.youtube.com/playlist?list=PLbGC44mjwqrd7CS25jngb...

Arainach 14h ago on HN
This is incredible - great presentation, great visualization. This is a topic I've often pondered in free time (but never properly researched), and seeing the visualizations was a huge help.
mhb 8h ago on HN
Once a year display of large steam engines running in Providence, RI at the New England Museum of Wireless and Steam. Saturday, October 10:

https://newsm.org/

mawise 7h ago on HN
In the animations of the screw cutter, is the threading reversed on the screw that moves the cutting tool? I was staring at the point where the threaded screw meets the carriage in the first animation to see if the carriage was moving very slowly, or just looping in place. It looks like the threads would push the cutting tool in the opposite direction of where it is actually moving.

Very nice work, thank you for sharing!

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