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Letter Re: The Tomato Rebuild--Machining Technology is Crucial to Modern Society, by Thomas G.
Jim,
After reading the recent letter by Thomas G, I felt compelled to offer a response
to demystify some of the technologies he talked about. First, I am a tool
and die maker for an ammunition manufacturer. If it's broken, I fix it, if
we need it, but can't buy it, I design and make it.
From reloading dies, case feeders, powder measures, primer feeders, cold header
press parts, I have done a lot. So I feel somewhat qualified to shed some light
onto how things are done. I'll start basic, and then work up to complex.
Aside from the technology of making metal, the most basic component is arguably
the screw, or the nut and bolt. While these can be made on a lathe, that's
simply not practical in the world of mass production. Since at least the turn
of the previous century (1800-1900) bolts have been made using machines called
headers and rollers. Headers come in two forms, cold and hot. A cold header
is typically used for making bolts, these take wire (and by wire, I mean form,
not size) the wire is then cut, and pushed into a die. A forming die will then
come down and crush the wire that sticks outside the base die, this forms the
bolt head, this can also be done for nails, rivets, screws etc. In the case
of bolts and screws they are then dropped into a thread rolling machine. This
is a device which has two panels which have flattened threads cut onto them,
the bolt rolls between the two panels and is threaded.
Nuts are made by hot-heading. A slug of wire is heated until it's pliable,
and is then smashed into a form. When it's cooled it's then threaded using
a tap.
Gears are made on machines called hobbers, but can be made on a horizontal
mill, or a shaper with an indexing head. The hobber works by holding a gear
blank between centers, and then has a cutter that rotates above the gear. Once
a gear is made, it can be used as a template for casting more, either die cast,
or sand cast, depends on size and material.
A lathe is a fairly basic machine, if anyone has ever seen a wood lathe, a
metal lathe works on the same principle. If you can build a wood lathe, you
can build a metal lathe in a number of iterations. Given the scrap available
from even a post-collapse society cobbling a functional lathe together should
be fairly easy. The same applies to a mill.
For those who have interest, I suggest checking out the gingery machines web
site, and perhaps even buying the book set. While a long time ago I decided
it was
easier to buy and rehab an old lathe than to build a new one, the books will
give even the novice user a good idea about how machines are made.
It is important to note that most machine tools were conceived back in the
1800s. With a few decent measuring tools, almost anything can be made. The
greatest thing about the age we live in currently is our ability to measure.
If you have a few decent sets of dial calipers, a few dial indicators, a pyrometer
(for heat treating) and a stop watch, you can produce just about anything you need.
At times after reading "Patriots" I
laugh at the [refugee] character who was the machinist, (Lon Porter) since
he carried his tools around in a bicycle trailer. While one tool box may satisfy
the
storage space required for some measuring tools, it would take a truck to move
all
of the various tools (tool bits, drill bits, mills, punches, indicators, angle
finders,
etc) that I would consider ideal for a post-apocalyptic machine shop.- AVL
