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Why wasn’t the steam engine invented earlier? Part III

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Re: Why wasn’t the steam engine invented earlier? Part III

#101

Post by baking »

throwawayffffas wrote: post #44
red_admiral wrote: post #13

Relevant recent ACOUP (Brett Deveraux) post: https://acoup.blog/2022/08/26/collections-why-no-roman-indus...

Just came here to link this. Tldr: There was no use case for low power steam engines in the ancient/roman world. There was no know-how on building high pressure vessels that would allow higher power steam engines (this know-how was gained by work on cannons). The key use case for the first practical engines was draining coal mines, in the ancient/roman world this was not a big problem because most of their energy was…

Also, transportation of fuel by animal power was inefficient so basing the steam engine at the source of the fuel (a coal mine) was the only practical first application. It wasn't until the steam engine was perfected that it made sense to transport fuel.

Re: Why wasn’t the steam engine invented earlier? Part III

#102

Post by gw99 »

Damogran6 wrote: post #68
steveBK123 wrote: post #35

Earlier quoted context omitted.

Modern people overestimate how long we have been able to engineer things precisely. I used to use a lot of vintage German cameras. Really right up through the 1950s the tolerances were wide enough that no two cameras were exactly alike. The parts were all replaceable, and there were often adjustments & shims inside to keep things in spec. For example, one camera might have part A that's a little long so it's matching…

I had a 89 Corvette...designed in the late 70's early 80's before computers were generally used to do so. It was a mass of shims and slotted holes to get things to line up. I had a 1998 Corvette...designed in the early 90's with CADCAM. No shims. Things like a door latch and door made by entirely different companies, the three holes to attach the latch weren't shimmed or slotted, and the replacement fit exactly with…

Same as the old land rovers I used to work on. 2mm was considered miraculous tolerances anywhere. If something didn't line up it usually got hit until it did.

Re: Why wasn’t the steam engine invented earlier? Part III

#103

Post by ravedave5 »

cptaj wrote: post #18

An important factor seems to be precision engineering. I saw the point made in The Perfectionists: How Precision Engineers Created the Modern World by Simon Winchester, where they argue that while all the science and experimentation was there, it wasn't until precision parts were widely available that steam engines really solved all their problems and became viable https://www.goodreads.com/book/show/35068671-the-per…

The Antikythera mechanism is shockingly precise for how old it is. (100-200BC)

Re: Why wasn’t the steam engine invented earlier? Part III

#104

Post by thfuran »

anjc wrote: post #97
hef19898 wrote: post #85

Earlier quoted context omitted.

Cameras always have been optical appliances. And as such they in deed do require a lot of precision. Especially those with changeable lenses, unless you don't mind your focal plane not being where your film, or nowadays sensor, is.

I presumed OP was talking about winders and so on. If shims were used for critical elements like optical alignment, I'm guessing that it's because this was the cheaper route to precision, rather than due to an inability to measure and manufacture precisely.

Cost is always a factor in manufacturability.

Re: Why wasn’t the steam engine invented earlier? Part III

#105

Post by feoren »

derekp7 wrote: post #47
jiggawatts wrote: post #14

Earlier quoted context omitted.

A nice explanation for the "rate of progress" is the percentage of the population that is not involved in the production of food. Since the dawn of humanity up until "very recently" in the grand scheme of things, something like 95 to 98 percent of the population were directly involved in food production. There were the odd shamans, priests, tribal leaders, or what have you, but everyone else made themselves busy hunt…

The question I have is how did mega projects in ancient times (such as the Pyramids) get enough people to work on them, and still have enough food to feed them? Or were the people on those projects (and other city-building projects at that time) only less than 5 percent of the total population? Also, is that 95% that are spending the majority of their time on food production? Or is that including people that spend a…

During the fertile season, right after the floodplains were flooded, you needed an enormous amount of labor to take advantage of the huge area of freshly-fertilized soil. Presumably this area needed to be tended and maintained, and then of course the harvest was another time when you needed enormous amounts of labor. And then you've harvested and the plains are briefly fallow, then they get flooded by the Nile for a few weeks, and there's nothing to do. So you have an enormous amount of labor power with nothing to do for a couple months every year. Why not pay them a little to lug massive stones around to build a monument to your awesomeness? Better than having them idling in the streets!

Re: Why wasn’t the steam engine invented earlier? Part III

#106

Post by retrac »

fortran77 wrote: post #40

I always wondered why the phonograph wasn't invented earlier! As soon as people were able to build geared mechanisms, they should have had the machining skills to build a simple cylinder photograph.

It almost was! In the mid-1850s a French inventor, Edouard-Leon Scott de Martinville, was studying sound, and he invented a device that could record it [1]. It was a diaphragm attached to a very lightweight pen, and when paper was drawn through it at high speed as sound was produced, it basically drew the waveform. He used it in his study of phonology.

So close! And yet no way to play it back. And trying to come up with some way to play it back seems to have eluded him, and others for a couple decades. Some of de Martinville's recordings have survived, and today software can reconstruct them into almost-intelligible speech and music. They're the oldest known recordings of a human voice.

[1] https://en.wikipedia.org/wiki/Phonautograph

Re: Why wasn’t the steam engine invented earlier? Part III

#107

Post by grogenaut »

steveBK123 wrote: post #35
cptaj wrote: post #18

An important factor seems to be precision engineering. I saw the point made in The Perfectionists: How Precision Engineers Created the Modern World by Simon Winchester, where they argue that while all the science and experimentation was there, it wasn't until precision parts were widely available that steam engines really solved all their problems and became viable https://www.goodreads.com/book/show/35068671-the-per…

Modern people overestimate how long we have been able to engineer things precisely. I used to use a lot of vintage German cameras. Really right up through the 1950s the tolerances were wide enough that no two cameras were exactly alike. The parts were all replaceable, and there were often adjustments & shims inside to keep things in spec. For example, one camera might have part A that's a little long so it's matching…

Modern items have stickers about warranty void if you open it, etc, other warnings like that. My 100% user serviceable coffee machine recommends you send it to them, cars encourage you to go to dealers. I don't see how that sticker is different in the 50s and now. There's a profit motive for them to fix it for you even if they don't charge it's still reputational (they stand behind their work).

Having this sticker on my device doesn't make me think that I need to send it in often, it's more that they're covering their ass.

The rest of your comment I'd agree with but a lot of things were designed around needing tight tolerances and using tight tolerances when you don't need them is not always a good idea. My earbuds won't charge if there's the tiniest bit of dust in the little recesses the charging pins go into or in the bottom of the well. Lower precision there would make them more reliable.

Re: Why wasn’t the steam engine invented earlier? Part III

#108

Post by adrianN »

virtualritz wrote: post #48
cptaj wrote: post #18

An important factor seems to be precision engineering. I saw the point made in The Perfectionists: How Precision Engineers Created the Modern World by Simon Winchester, where they argue that while all the science and experimentation was there, it wasn't until precision parts were widely available that steam engines really solved all their problems and became viable https://www.goodreads.com/book/show/35068671-the-per…

In the 80's my uncle, a trained mechanical engineer, tried to build a working scale small gauge steam locomotive at home for fun. He was a train geek. I reckon it was maybe 1/16 scale or the like. He machined all parts on his Emco Unimat II, a 70's hobbyist convertible lathe. The final piece was beautiful. Ultimately the kettle couldn't build up enough steam because of tolerances of parts. He machined the resp. parts…

I'd love to read a writeup on that project. Sounds fascinating.

Re: Why wasn’t the steam engine invented earlier? Part III

#109

Post by grogenaut »

Damogran6 wrote: post #77
virtualritz wrote: post #48

Earlier quoted context omitted.

In the 80's my uncle, a trained mechanical engineer, tried to build a working scale small gauge steam locomotive at home for fun. He was a train geek. I reckon it was maybe 1/16 scale or the like. He machined all parts on his Emco Unimat II, a 70's hobbyist convertible lathe. The final piece was beautiful. Ultimately the kettle couldn't build up enough steam because of tolerances of parts. He machined the resp. parts…

That makes me wonder if I could do so with my 1966 South Bend...but then I think I'd probably finish the cylinder bore with a cheap Chinese Reamer, which is not something he would have probably wanted to purchase for a one off operation. (Think $300 for a cutting tool, vs one I can buy today for $25) You bore thecylinder to rough dimension, then use the reamer to set it to final tolerance.

When making a real steam engine you use piston rings, you don't really machine to exact tolerance except where you're showing off how precise you are. The rings are consumable, they also flex since they're split rings (they're a C), which lets them expand as they wear. They're usually softer material or a slide compatible material with the cylinder walls. This makes them sacrificial and saves the much more expensive cylinder.

You see them in literally every modern engine and I'm sure absurdly far back, even though they have better precision now.

Your 1966 south bend is likely several orders of magnitude better than that emco, those things are more meant for wood, and imagine if you needed to align your spindle on your lathe every time you used it how inaccurate it'd be.

Re: Why wasn’t the steam engine invented earlier? Part III

#110

Post by lordnacho »

isk517 wrote: post #81
notahacker wrote: post #60

Earlier quoted context omitted.

Pyramids were built during offseasons. But it wouldn't really have been an option to redeploy that unskilled, uneducated labour towards industrial research instead, at least not without a radical change to ancient societies. Not least because kings and religions tended to want non-agricultural engineering resources focused on monuments and defences, not finding more labour/cost-effective ways of increasing output of…

Also wasn't ancient Egypt ridiculously fertile? I imagine being able to consistently produce excess grain means you can divert workers to other projects.

Plus don't forget why Egypt was fertile: The farmland got regularly flooded by the river. Can't do much while it's flooded, just go and help out on the pyramid project.
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