(JMartin957) writes:

You obviously like reading, and you obviously like thinking about the
consequences of what you are considering. Both of those qualities are
commendable. At some point, though, you actually have to do something.

I have done some things. I took a crash shop course in a physics department
a couple of decades ago in which I learned to use a lathe to make a plumb
bob which unscrewed into two parts. I also used the milling machine on my
own to take a piece of scrap aluminum (C shaped) and made it into a keyboard
with pushbutton switches for a computer I was trying to design at the time.

One of the most valuable lessons I learned from trying to design and build
the computer from scratch was how costly it can be to invest money in a
project without having thought it through completely. Since then, I'm a
lot more careful. Having experienced the difference, I prefer to err on
the side of caution.

Continuing with things I've done: as a result of reading Gingery's book on
the charcoal foundry, I built a little coffee can foundry, spent months
collecting discarded soda cans from the side of the road, consulted with
the local fire department about whatever regulations might apply and
eventually melted some aluminum. I also built some frames for metal
casting in sand. I didn't get further than that because I had to move
and all my tools wound up in storage, where they are still located.
So, at the moment, I have no tools except those in a little toolbox
that the landlord left in the apartment. That has been the situation
for a few years and I can't do anything about getting the stuff out
of storage. Fortunately, it isn't costing me anything.

Another thing I did was to design and build a blackboard that folds up
into a shopping cart that could be used to carry the materials I needed
to give lectures. (Never mind that it worked, but not very well, and looked
ridiculous.) That was mostly woodworking with a saw and hand drill, which
I also used it with an abrasive disk to cut some carriage bolts. I also
used a metal brush attachment to the drill to remove some paint and rust
from an old EICO oscilloscope. Also, when I was planning to give some public
lectures on mathematics at a local Barnes and Noble
(see http://www.swiss.csail.mit.edu/~adler/MATHCULT) and examining an
old overhead projector I'd been lugging around for a decade or so, I
accidentally broke one of the components, a thermostat that shut off the
machine when the temperature got too high. I managed to locate
the company that used to make it, get a schematic and parts list for
the projector and find a vendor that sold a suitable replacement for
the switch. I also realized that it was using asbestos, and found a
supplier who provided me with a safer material to replace it. This took
a few months. After that, I was able to use it in my lectures.

I've done other things, not very impressive of course, but I would like
to emphasize that I discussed most of them on this and other newsgroups,
along with my progress on them. So, if you have the impression that I
never do anything, you are mistaken.

The simple fact is that, for several reasons, it is a lot harder for me to
do things than it is for most of the other readers of this group. If I'm not
progressing quickly, I'm not happy about that either, but it is the best I can
do under the circumstances. I also know that I succeed occasionally and when
I do there is nothing quite like it.

Metalworking is a art in which skills have to be built on other skills. To
talk about buying a milling machine when you don't own a file and don't know
how to use one is like discussing the fine points of marathon running before
you have learned to walk. It's asinine.

How do you know I don't know how to use one? I have used files. I just don't
happen to have any at the moment, since they are all in storage. Oh, I forgot:
a few years before taking the crash course in the machine shop at the physics
department, I audited a few sessions of a class on metalworking at the
Museum of Fine Arts in Boston. I designed a certain sculpture based on the
Barromean Rings (you might know them as the Ballantine beer rings, i.e. three
rings which can't be separated but such that no two of them are actually
linked, i.e., if you cut out any one of the rings, the other two aren't
linked), cut out the parts with a hacksaw, and spent a lot of time smoothing
them out and trying to adjust their shapes to something I found aesthetically
pleasing with a set of little files. I was literally sculpting with the files.

Maybe you are referring to my earlier question about removing burrs from
parts of Harbor Freight machines, where I asked whether I should use a file
or a grinder, and mentioned that I have neither. That was probably a stupid
question, but it was motivated by the following considerations:
(a) I don't really know anything about the parts of the imported machine
that are going to need modification, neither their nature nor their
exact condition nor how much care will be required in modifying them,
given the uses to which they will be put.
(b) Although I'm aware of using a file to remove burrs, having done it
myself, I haven't done it recently and the topic wasn't fresh in my
mind.
(c) Even so, I've always regarded it as something one does to avoid getting
cut by the burrs, not as something one does to protect or improve
machinery, and therefore it is at least conceivable that some other
method might be recommended when it is not simply a matter of cosmetics
and of not getting cut.
(d) Finally, from a strictly logical point of view, the fact that one *can*
use a file to remove burrs doesn't mean one can't optionally use
something else instead. The idea that one might use a grinder occurred
to me off the top of my head, partly because I had been wondering whether
I ought to get one. If it is a bad idea to use a grinder to fix the
internals of Harbor Freight machines, that doesn't indicate that I don't
know anything about files: it indicates that I don't know anything about
grinders. And in fact, I don't, never having used one, even though I
read a little about them in Joe Martin's Tabletop Machining.
--
Ignorantly,
Allan Adler
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.