
Interchangeable parts revolutionised the way things are made - kitd
https://www.bbc.co.uk/news/business-49499444
======
rsj_hn
Fun Fact: One of the first mass assembly operations that used an early form of
interchangeable parts was the Venetian Arsenale, which could produce up to one
ship per day. The ships were floated down a canal in an assembly like manner
and fitted with pieces made by artisans to standardized specification,
allowing the same piece to be fitted to different ships as well as allowing
for pipelining. As ships were also repaired in the Arsenale, this could be
viewed as an early form of interchangeable parts as replacement pieces were
fitted from stock.

Also, Galileo visited the arsenale and was fascinated by the many interesting
questions of mechanics raised. For instance, why do the oars in the center of
the ship most account for the ships movement? Galileo experimented with new
oar designs as well as questions of naval architecture and artillery design,
eventually moving to Venice and working as a consultant for the Arsenale. It
was the world's first mass munitions factory.

Some links for further reading:

[https://italoamericano.org/story/2016-7-7/arsenale](https://italoamericano.org/story/2016-7-7/arsenale)

[http://echo.mpiwg-
berlin.mpg.de/content/shipbuilding/venice_...](http://echo.mpiwg-
berlin.mpg.de/content/shipbuilding/venice_arsenal/lettura_gal_html/LetturaGal.html)

[https://leanfactories.com/venetian-arsenal-venice-ship-
build...](https://leanfactories.com/venetian-arsenal-venice-ship-building-
using-mass-production/)

~~~
beerandt
The more I dive into the history of various technologies (and even
professions), the more it becomes apparent that militaries are responsible for
a _vast_ proportion of historical advancements, even in the most unexpected
areas.

Edit: Also responsible for a vast supply of historical datasets.

Edit 2: IMHO, the most fascinating is all the tie-ins between artillery,
spycraft, astronomy, aerospace/rockets, geodosy & cartography (and invention
of the chronograph), tidal monitoring & weather keeping, nuclear weapons, gps,
and probably a dozen more topics I'm forgetting off the top of my head.

Individually, each of these is a mammoth of a topic on its own. But the
interplay in their development (as influenced by big-picture military
strategy) is just mind-boggling to me. It is by far, the most interesting,
persistent, and deep rabbit-hole I've encountered.

(Hint: Ballistic missiles are essentially long range artillery. Hint 2: They
require gravitational variation to be taken into account for targeting.)

~~~
rsj_hn
I think this is absolutely correct. Huge advances are driven by war, for
obvious reasons -- survival is at stake. John Napier discovered the logarithm
due to his work on artillery. A lot of Archimedes's innovations were driven by
the desire to build weapons. The demand for accurate clocks was driven by the
Navy, giving rise to many innovations. And of course in the 20th Century,
integrated circuit design was driven by a desire to build computers that could
be embedded in ballistic missiles and withstand large amounts of heat.
Fairchild semiconductors' first big contracts were primarily for defense and
NASA.

------
pssflops
I am rather concerned that this failed to leave out Eli Whitney[0], whose
contributions for interchangeable gun parts were taught to me in university
history class.

> By January 1801, Whitney had failed to produce a single one of the promised
> weapons, and was called to Washington to justify his use of Treasury funds
> before a group that included outgoing president John Adams and Jefferson,
> now the president-elect. As the story goes, Whitney put on a display for the
> group, assembling muskets before their eyes by choosing (seemingly at
> random) from a supply of parts he brought with him. The performance earned
> Whitney widespread renown and renewed federal support. It was later proven,
> however, that Whitney’s demonstration was a fake, and that he had marked the
> parts beforehand and they were not exactly interchangeable. Still, Whitney
> received credit for what Jefferson claimed was the dawn of the machine age.
> [0]: [https://www.history.com/topics/inventions/interchangeable-
> pa...](https://www.history.com/topics/inventions/interchangeable-parts)

------
madengr
I believe 1911 (handgun) slides and frames still have to be hand fit to one
another. Though there is a company claiming tight enough tolerances that
theirs don’t. I have two identical 1911, but have not tried it.

I wonder how original Colt 1911 were produced for military orders? I can’t see
hand fitting those.

The AR-15 is fully interchangeable, but I have read of takedown pins on Colts
not fitting more modern lowers receivers. Also wonder if the gas system has to
be tweaked? The FN-FAL has an adjustable gas block, but that may be due more
for ammo than parts compatiblity.

~~~
dsfyu404ed
Sounds like an urban legend. Colt and John Browning shipping something that
needs to be hand fit doesn't pass the smell test. Major world powers don't
adopt a gun that can't have parts interchanged as their standard sidearm in
the early 1900s. For a specialty weapon of 30yr earlier maybe but only the
cheapest of "boring old small arms" were still being hand fit around that time
and even then it was rare in industrialized countries.

Edit: adjustable gas systems are in fact there to tune for ammo variations and
fouling.

~~~
madengr
I don’t think the original 1911 were hand fit, but all of the modern, upper
tier 1911 claim to be hand fit. Why the purpose behind this; reliability?

~~~
dsfyu404ed
If you're really lucky hand fit translates to "our QA department is stocked
with measuring tools and they actually use them to confirm parts meet spec
before being assembled, maybe if you're lucky they write down how over/under
something is so that the assembly guys can pick combos that work well". (If
you're paying big bucks this is hopefully the case.)

More likely it means someone cycled the thing to make sure it worked before
slapping their "qa by <unintelligible scribble>" sticker on the product or
packaging

It's mostly just marketing mumbo jumbo to make it seem like a fancy hand
crafted product. Back in "the day" the marketing people would have advertised
that things were made by precision machines. Today labor is expensive and
machines are cheap so they're advertising that they put a lot of labor into it
in part to justify the price (and the reverse would have been true in the
early 1900s, they'd emphasize the machine contribution).

Firearms are tight like a retired hooker compared to the kind of tolerances
any reasonably modern manufacturing operation of that sort (mostly machining
and stamping/forming) is capable of working in (they need to be loose so all
those steel on steel parts will move like they're supposed to). Loose fitment
tolerances translate to less need for super precise parts to begin with. Say
you have a slide that wants .010"+.002"/-0001" of clearance. Sure you _can_
make that part to .0005 but insisting on that level of consistency just adds
unnecessary cost to do so when you have an entire .0003" space to shoot for.

For ultra high precision stuff tighter tolerances and more consistency are
used but that's mostly limited to the pressure bearing parts of the action
that touch the case/bullet (the goal is to get that cartridge to fit in there
the same way each and every time).

Some of the most reliable firearms out there use very loose tolerances. For a
1911 I feel very safe saying that the modern high end ones do it more because
they can than because it improves performance in any measurable way. High end
guns almost by definition will never see enough use to get to the point where
manufacturing it more precisely could ever effect reliability.

------
phreeza
Reminds me of this article, which I think was also discussed on HN

[https://www.ribbonfarm.com/2012/03/08/halls-law-the-
nineteen...](https://www.ribbonfarm.com/2012/03/08/halls-law-the-nineteenth-
century-prequel-to-moores-law/)

------
jotm
I never even considered that early machinery was custom made and had no
readily available parts. I guess for any repairs, you had to go to the
original maker, who would create a replacement part that would only fit on
your machine.

Seems like a really simple concept, just like the drill press for that matter,
but it took so long for people to realise the potential.

~~~
KineticLensman
Also true of the most basic components that we take for granted now, e.g.
screws. The concept was known to the ancients, but they weren't mass produced
as fasteners until the 1760s [0]

[0] [https://en.wikipedia.org/wiki/Screw](https://en.wikipedia.org/wiki/Screw)

~~~
HeyLaughingBoy
I remember watching a documentary about a country in central Africa where,
less than 15 years ago, blacksmiths were making screws and nuts by hand. They
needed to be kept together or the manufacturing variations would mean that
last week's screws might not fit this week's nuts.

These guys were fast, but nowhere remotely as fast as thread-rolling machinery
of course.

------
marktangotango
The Packard Merlin is an interesting story. The famous Rolls Royce Merlin was
widely used in allied fighters and bombers during ww 2, but many parts where
manually fitted. When licensed to the American auto manufacturers to mass
produces, they tightened up the specifications and changed the things like the
bearings.

[https://en.wikipedia.org/wiki/Packard_V-1650_Merlin](https://en.wikipedia.org/wiki/Packard_V-1650_Merlin)

