From: "Wayne Bengtsson"

(snip a very good post, most of which I was only able to scan without my
head imploding)


Yeah, I hate when that happens, don't you?

The effect of size, and the machinery/effort needed to move parts
from A to B to C. Even just setting up a system for tracking complex
machined parts, and making sure the right parts are in the right place
requires considerable effort, and not a little human intervention at times.


The theoretical understanding reduces this problem to general principles
guiding "what to do first" and "what to do next" that are subject to
insufficient analysis and bookkeeping errors in the finite solution by finite
methods. So the inventorying can self-check and self-repair by comparing a
description of what's going on with the "wave function" that describes
everything that can be known about what's going on, without actually knowing
the wave function at every point in time.

Another factor missing from your equations is the tendancy to "stretch"
tools, or use them on parts larger than what they were designed for.

Answered in my reply to John.

You see, it's the difference between a woodworking shop and a machine shop.

The jig guides the tool;
The jig guides the tool;
Hi, ho, the Derry, Oh,
The jig guides the tool.

In woodworking the work is fed into and THROUGH the power tool by hand, mostly,
and in any case can be larger than the tool. Mostly a linear process. But
what's going on is feature projection of an unusual kind.

GD&T teaches us that we need to screw a tap into a hole with a known fit and
"project" the hole outwards to where the coordinate measuring machine, or one
of us, can measure its location. The process of mathing a transmission and
engine that have never met, using a plate between, is feature projection: The
holes on the engine and the holes on the transmission are both projected onto
the plate so the plate can serve as an adapter.

So what's happening when you rip the edge off a board, or mill a BP x axis
table by sliding it through a custom fixture, is that the flat, linear surfaces
on the table saw or on the rough table are projected to and at time same time
averaged with the produced surface, which improves that surface. Then, that
improved surface becomes the guide and what was the guide surface is run
through, a little closer this time, to improve it. So progress is made and the
work envelope problem is solved by unconventional use of whatever's available,
which is what got us through WWII, with drill presses used as milling machines,
and milling machines used as lathes, three shifts.



If you have one shop merrily
self replicating, you soon need to build another 5 just to house all the
other self replicating machines. Can you say "grey goo"?

Yes, but that is a self-reproducing automaton, and I am only talking about
manually guided machine tools capable of assisted reproduction, not
autonomously reproducing machine tools proliferating with no antibiotics in
sight.

Is this the best possible way to spend
your limited time on this ball of dirt?

Yes. It's my job.

In experimental machine work, we use both woodworking and metalworking machines
and principles, and the Smithy Super Shop is an experimentalists's dream tool,
though its potential for SR is unknown to me. In woodworking, you sometimes
make a fixture for just one use. In metalworking, usually a fixture is built
for mass production. Different paradigms. Same jig and fixture technology,
though. Kinematic contraint.



Yours,

Doug Goncz
Replikon Research (via aol.com)

Nuclear weapons are just Pu's way of ensuring that plenty of Pu will be
available for The Next Big Experiment, outlined in a post to
sci.physics.research at Google Groups under "supercritical"