Building the difference engine and analytical engine in 1878--how tough?

The difference engine and analytical engines were designed in the 1820’s and 1830’s, but building them was impractical due to the expense involved, and tolerances that were very difficult to meet at the time. I'm assuming that, in the timeline I'm rebooting, that there is a serious push to build them.

Does anyone know enough about 1870’s manufacturing technology to assess how hard it would be to build them in the late 1870’s? Money is available—how much are we talking about? The cost of a house? The cost of a destroyer? Of a battleship—or a division of battleships?

Ultimately, the USA wants multiple difference engines, along with some analytical engines, at the Naval Observatory in DC, or a different facility if need be. If it proves practical, others will be sold to defray the costs, or perhaps sold at subsidized costs to universities with good mathematics and astronomy departments.

Would the machines be better off somewhere with less heat and humidity—like a deep underground room where the temperature and humidity are nearly unchanging?


The United States is REALLY wanting the capabilities that these machines could offer, specifically for computing orbits of anything and everything that can be detected. Congress, of course, wants them built in the USA.

The timeline I’m rebooting features a meteor impact that leaves a crater almost a mile across where the town of Lincoln, NH had been, in 1876 in New Hampshire, and there’s a resulting serious concern about the possibility of more…

The funds for the computing engines were voted out in haste shortly after the disaster; a knee jerk reaction in Congress has given the navy plenty of funds to build these machines. I’m more concerned about how hard it will be to build, than if the funds will keep flowing; assume that they will, even if it means fewer shore batteries or Gatling guns, or an increase in revenue tariffs.

The need is there, the funds are there--BUILD THEM!

(Even though some might put the meteor impact in ASB, the questions about the technology are relevant for many timelines, so I put it here.)
 
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The difference engine and analytical engines were designed in the 1820’s and 1830’s, but building them was impractical due to the expense involved, and tolerances that were very difficult to meet at the time. I'm assuming that, in the timeline I'm rebooting, that there is a serious push to build them.

Does anyone know enough about 1870’s manufacturing technology to assess how hard it would be to build them in the late 1870’s? Money is available—how much are we talking about? The cost of a house? The cost of a destroyer? Of a battleship—or a division of battleships?

Ultimately, the USA wants multiple difference engines, along with some analytical engines, at the Naval Observatory in DC, or a different facility if need be. If it proves practical, others will be sold to defray the costs, or perhaps sold at subsidized costs to universities with good mathematics and astronomy departments.

Would the machines be better off somewhere with less heat and humidity—like a deep underground room where the temperature and humidity are nearly unchanging?


The United States is REALLY wanting the capabilities that these machines could offer, specifically for computing orbits of anything and everything that can be detected. Congress, of course, wants them built in the USA.

The timeline I’m rebooting features a meteor impact that leaves a crater almost a mile across where the town of Lincoln, NH had been, in 1876 in New Hampshire, and there’s a resulting serious concern about the possibility of more…

The funds for the computing engines were voted out in haste shortly after the disaster; a knee jerk reaction in Congress has given the navy plenty of funds to build these machines. I’m more concerned about how hard it will be to build, than if the funds will keep flowing; assume that they will, even if it means fewer shore batteries or Gatling guns, or an increase in revenue tariffs.

The need is there, the funds are there--BUILD THEM!

(Even though some might put the meteor impact in ASB, the questions about the technology are relevant for many timelines, so I put it here.)

http://www.computerhistory.org/babbage/modernsequel/

a working Difference Engine has been built using tolerances and materials that Babbage would have had available.
So, you don't have to wait for the 1880s, you just need a good project engineer and lots and LOTS of money.
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See also
WI: Babbage completed the Analytical engine in the 1870s? (Multi-page thread 1 2)
SPJ
What if Babbage's Difference Engine had been built and used? (Multi-page thread 1 2)
JJohnson

(several other threads, but I think these are the most relevant.)
 
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http://www.computerhistory.org/babbage/modernsequel/

a working Difference Engine has been built using tolerances and materials that Babbage would have had available.
So, you don't have to wait for the 1880s, you just need a good project engineer and lots and LOTS of money.

I know it could be built earlier--but how hard would it be to make one in the late 1870's; that's when my timeline will have a perceived need and a willingness to spend lots and lots of money, first for a difference engine--then several of them--then going to analytical engines. Precision manufacturing has certainly improved..but by how much. Could they become semi mass produced items, or is that in the future?

And how bad a hit on the budget will the machine be?
 
Well a bit of a plug, shameless maybe, but I have touched on this question in my TL The Suns Never Set, on the ASB part of the board. By the 1870's it should be doable by the 1880's yes. The best firms to make it would be large watch and clock makers.
Money would be an issue but not that big by 1879.
 
The issue is getting Babbage to actually finish his plans for a Analytical Engine. He kept reworking and rewriting plans for it (the man was a...perfectionist...to put it politely.) Add in his other projects and fight with street musicians and an inability to allocate approved funds in a especially wise manner, and you're dealing with plans that either need to be finished by him or someone smart enough to puzzle them out and finish them.

I'd actually read some of Sydney Padua's notes for her Babbage and Lovelace webcomic, which details a lot of information that might be useful.
 
OK....

Looking around the internet, the Scheutz (father and son) built a couple of difference engines (with printers), selling one to the US for 5000 (US$?) and another to Britain for £1200 (on which they took a major loss, admittedly).

http://history-computer.com/Babbage/NextDifferentialEngines/Scheutz.html said:
Unlike Babbage, the Scheutzes were an eminently practical pair, and the Tabulating Machine, as they called it, was completed on schedule (though not within the budget and prone to error). The first machine, which was ready in October, 1853, was built under the supervision of Edvard Scheutz in the workshop of the industrialist Bergström. The machine (see the lower photo) could handle numbers of 15 digits and tabulate functions with 4 orders of differences (the fourth being constant) and print out results, rounded off to eight digits, on molds from which metal printing plates could be cast. .

Now, $5000 was a big chunk of money back then, but not compared to warships, say.

The USS Monitor, for instance, was $275,000.

Now. An analytic engine? hmmmm... I suspect you'd be better off buying more difference engines and hiring mathematicians, astronomers and clerks...

The US machine was used for astronomical purposes
ibid said:
In 1856 the machine was purchased for 5,000 by Dudley Observatory at Albany, New York, USA and the next year was transported to the USA, where it was used for the first practical work—a computation of the True Anomaly of Mars.


So, 20 years later, the prices would presumably be even lower, and capabilities higher.
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I've looked for estimates on the relative complexity of the Analytical Engine (vs the Difference Engine) and can't find them.
 
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getting the plans/patents

Babbage died in 1871, and the demand in my upcoming timeline for computing machines won't start until late 1876/early 1877. The meteor strike is in June of 1976, so it will take some time for the need to percolate up to the powers that can authorize money for it.

So, what plans could be obtained legally?
 
Babbage died in 1871, and the demand in my upcoming timeline for computing machines won't start until late 1876/early 1877. The meteor strike is in June of 1976, so it will take some time for the need to percolate up to the powers that can authorize money for it.

So, what plans could be obtained legally?

From what I can tell, the Scheutzes didn't make a direct copy or even have access to plans or drawings, but designed their own machine based on what they could see/what they heard.

If so, patents and drawings are not anything you need to worry about.
 
Buildable--interchanbgeable parts? how are the tools?

OK--this is a big help. It CAN be built, and can be afforded. But how good are the precision manufacturing techniques in 1876 USA? Can they be semi mass produced, or is each one going to be a near hand crafted masterpiece? The era of interchangeable parts is here; can the machines be made with fully interchangeable parts, or is the time for that not yet? The parts are going to be much more precisely made than the rifles and the like that interchangeable parts were demonstrated on.

Now that I know it CAN be done, I need to assess how bad the cost is, and how many can be made, so I know if Congress funds 3 or 4, or dozens.
 
OK--this is a big help. It CAN be built, and can be afforded. But how good are the precision manufacturing techniques in 1876 USA? Can they be semi mass produced, or is each one going to be a near hand crafted masterpiece? The era of interchangeable parts is here; can the machines be made with fully interchangeable parts, or is the time for that not yet? The parts are going to be much more precisely made than the rifles and the like that interchangeable parts were demonstrated on. ...

a look at the top grade navigation & astronomical chronometers would be a guide. if those could be built in quantity the it augurs well for your engines.
 
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