Ignoramus689 wrote:
What was the most ill-conceived, unsuccessful, and worthless/expensive
DIY style project that you undertook (I would say without counting any
injuries as they could outweigh everything else)?

My biggest one is a shed that I built. Not counting my shoulder sprain
due to a posthole digger, the shed is way too narrow to be truly
useful. It is attached to the deck along its longer side, so it is
inconspicuous, but if it was 3-4 feet wider, it would have been a lot
more useful. The shed stands, is dry, and functions as designed, but
it was poorly designed.

i
Well, I have a couple derelict projects, maybe not what you are
looking for, but ....

I tried to build a hybrid electric car. A friend donated a
massively rusted out VW bug, no floor on driver's side, you
could see both rear tires from the driver's seat, etc. I cut
out a piece of scrap and welded a new floor onto it. I think my
welder at the time might have been 48 V worth of trolling motor
batteries for the car. I got a Kaylor adaptor which mounts a
jet engine starter/generator to a VW flywheel. I built a
switching regulator for the generator shunt field, and I could
vary motor speed from about 3000 - 7000 RPM or so. I had some
big transistors to switch the armature, but never built that
controller. So, I had a spool of wire as a starting resistor
and just blipped that and then cut in the main relay, and it
sounded like a jet engine! The particular motor/gen I got had
such a light field structure it vibrated as the armature slots
went by. I had to make the giant bayonet fixture that holds the
motor/gen on the Kaylor adaptor, it didn't come with the
motor/gen. That actually came out OK, I would have been REALLY
****ed to chew up what would now be $100+ of aluminum and have
it not fit right. I had few measuring tools or precision setup
skills at that time. It was too big to fit on my 10" Atlas
lathe at the time, so I had to do it all on a rotary table on my
mill.

Anyway, the thing actually ran as an electric car. I have no
idea how far it would go on a charge, 4 90 AH trolling motor
batteries aren't a huge amount of energy. It did run quite
well, I ran up and down some hills near my house. I think it
probably was snappier than the original VW engine.

Then, I tried to put in the hybrid conversion. I bought a Honda
350 engine from a guy who I should have been more wary of.
After I cleaned the thing up, I found obvious signs the serial
numbers had been chopped up with a chisel. I eventually got the
engine running as is, it ran incredibly rough, and blew a lot of
smoke. I was never able to keep it running more than a minute
at a time. I don't know if it had an ignition problem, or what.
Anyway, I plunged ahead, building a frame for the engine, and
then modifying it to bring an extension of the crankshaft out
where the centrifugal oil separator was. I made an adaptor to
plug in where the oil separator cap went on the side cover that
brought the oil ports out to where I could hook up an external
paper filter. I added an oil pressure gauge, and it went so far
past 100 PSI that it bent the needle hammering it against the
zero peg. I made a totally horrible resilient coupling to a
stratofortress generator, that is a work of lightweight
mechanical art (the generator, that is). 400 amps at 30 V, and
the thing weighs about 30 Lbs! My coupling was way out of
balance, and didn't have anywhere enough resilience to handle
the uneven power strokes of the vertical twin Honda engine.
(With the pistons 180 degrees out of sync with each other, the
power strokes happen 1/2 rev apart, then there's a full rev and
a half with no power stroke.) After a couple short runs, a
disassembly showed the crankshaft extension was twisted, and
would obviously break within a couple more minutes' run. I was
going to have to redo that whole thing with a MUCH heavier
shaft. That is about where the project stopped. I still have
the jet engine starter motor, the Kaylor adaptor, the stratofort
generator, and the electronics. I gave away the Honda engine,
but one carb off it is on my lawn tractor. I kept the
trolling batteries for a while, but didn't bother to keep them
charged. While trying to recover one of them that wasn't
charging, I increased voltage to try to get it to take a charge
without realizing an intercell connection had gone open, I
managed to blow the top off the battery with a hydrogen
explosion. it sounded like firing a 12-gauge in the basement.
I'm damn lucky it was triggered up on top of the electrolyte or
I might be typing this on a Braille keyboard! Sheesh, how
stupid one can get sometimes! I sold the VW to a guy who needed
a good transaxle. This all happened about 1982 - 1985 or so.
I remember wrestling my 100 Lb vacuum-tube oscilloscope down the
steps to the garage to work on the switching regulator circuit.

Another insane project was building a 32-bit bit-slice computer.
The main CPU section was built on two hand-made wire-wrap boards
about 14" square. It had 16 K words of 96-bit wide control
store for the microcode. I actually got it running at the
blinding rate of 8 MHz for 2-register operations and 6 MHz for
3-register. I wrote an emulator in BASIC and a macro assembler
for it, and had a pretty sophisticated (for the time) download
and diagnostic system for it that ran on a Z-80 system with
S-100 bus and PC/M. (Is that the right OS for the old S-100
systems?) I was going to implement a 32-bit microprogrammed
computer with it, based loosely on the IBM System/360, and then
have to adapt an OS to run on it. Well, I got bogged down in
microcode, and never got anywhere NEAR finishing the thing.
Then, it became possible to buy a DEC MicroVAX-II CPU piece by
piece from brokers, and I never looked back! I still pull out
the huge wire-wrapped boards for visitors to marvel at.

All of my purely mechanical projects usually work in some
fashion, sometimes after a little adjustment, and seem to serve
their purpose. They are usually a lot less ambitious than the
two above.

Jon
Jon