20 Mar
2005
20 Mar
'05
10:32 a.m.
On Sat, 19 Mar 2005 16:28:45 -0500, Scott Stevens <chenmel at earthlink.net>
wrote:
Agereed. I think that _most_ mechanical parts for classic computers could
be made ina good home workshop, with the exception of disk/tape heads,
and probably bits for inside HDAs. That still leaves a lot that could be
made.
I certainly think that any part for, say, an ASR33 could be made at home.
It may not least as long as the original, but do you really need to run
the machine 24/7? :-)
Which, alas, leaves storage devices as the main problem. Apart from
heads, I think parts for floppy drives could be made at home. Hard drives
are a lot worse. Even things like the spindle for an RK05 would be a
serious project (does that one have a ferrofluid seal in it? Some drives
certainly do).
On Fri, 18 Mar 05 07:39:43 GMT
msokolov at ivan.Harhan.ORG (Michael Sokolov) wrote:
Hmm... Drivesmith... one problem, of course, is that the tolerances
for hard drives are somewhat tighter than for strictly mechanical
devices such as steam engines and guns. I know people who make both
(steam and guns), but I would seriously hesitate to make any sort of
drive bits newer than, say, an RK05. As I have stated many times before, I believe the
solution is for us
to open our own factories to make them.
I suspect, rather than 'factories', that it would be similar to being a
'gunsmith.' There are plenty of artisan machinists who make all sorts
of complex machinery.
Having said that, someday I know I'll have to face at least one round
of this... I have several DF32 drives that I expect have seriously
worn plating (I've only ever tested the electronics, but I _have_ spun
the platters up and down, 20 years ago, long before I knew it could
cause a problem). Getting a replacement platter fashioned and turned
to suitable smoothness is completely within the realm of accessible
tools for steam engines, etc. It's really no worse than turning a
brake rotor. My only real concern is _plating_ the platter. Setting
Sure. I suspect you could skim the surface of the existing platter rather
than start from new (I can't believe the thickness is very critical). Of
course you would have to replate it.
up an electroplating rig is easy enough (I copper
plated a number of
nickels and quarters as a lad ;-) presuming one can a) come up with an
acceptable formula for the coating, and b) gain access to the various
I thought it was mostly nickel, but I am not sure.
soluable compounds to mix up a batch of plating
solution. Even when
Indeed. I know the gold plating is not something to try at home... (the
only reasonable method uses gold cyanide..). If you could find out what
metal(s) the plating consisted of, you could probably find details of the
chemicals to use in some of the old books on workshop methods or
electrical engineering that Lindsay have reprinted. I am pretty sure I've
got this info somewhere.
that's done, one still has to construct the timing
track generator,
but at least that's well documented, so one could build the real deal
from old DEC bits, or one could simulate a formatter with modern
circuitry... the timing pulses are not that bad.
Vince and I have also kicked around what it would take to build a
modern solid-state replacement for just the rotating media (there's
already a prototype 74LS replacement for the entire 4-drive
assembly)... it's honestly easier to replicate the entire drive
assembly (since that can be done with 100% digital circuits), but the
whole point would be to have a modern replacement _just_ for the
platter and possibly the heads.
And it would probably be even eaiser to get the whole machine, storage
and all, into a couple of FPGAs, or as a software emulator...
I guess I am odd, but I feel that the peripherals are as much a part of
classic computing as the CPU. Sure it can be fun to design new
peripherals for the classics, to link CF cards to a PDP8 or whatever.
It's also good to keep the origianl peripherals running.
-tony