27 May
2005
27 May
'05
6:10 p.m.
On Fri, 2005-05-27 at 01:56 +0100, Tony Duell wrote:
It's the sort of tool that not many people have though. Why make life
That is not an excuse. Anyone working on IBM 5155s (or for that matter
Friden Flexowriters, which are stuffed with setscrews needing Bristol
Spline drivers) should have a set.
Oh heck,
yes. I went through every alan key and torx bit I had trying to
find something that would fit the former. Ended up with a good ol' pair
of long-nosed pliers, and those bristol spline screws are getting
replaced with something a little more conventional on reassembly!
NO!! Those screws are part of the machine and should be kept. I feel very
strongly about keeping odd fasteners, etc in machines, to replace them
with anything else does change the character of the machine IMHO. Surely
you can buy a set of Bristol Spline keys (I think Farnell do them...) difficult for the next person who comes along and has
to fix the
machine? The only reason I can think of for using those screws is that
people were expected to go inside the case to swap cards every so often,
but they weren't supposed to be poking around in the display section.
That was exactly the reason (and the reason for using tamperproof Torx in
the PSU). Customers were only supposed to have normal tools, Failed
Servoids hat the Bristol spline tools as well (but couldn't therefore
open the PSU case).
According to one manual I've got, if an IBM service engineer saw that the
tamperproof torx screws on the PSU had been replaced with normal screws,
or had been moodifed to allow a normal driver to get them out (e.g.
removing the cerntal pin or cutting a slot across them), said engineer
was supposed to replace the entire PSU (and charge the customer for it!).
That requirement's gone now; if someone owns one of these beasts these
days then they're presumably just as likely to be inside the display
section to fix stuff as they are digging around in the rest of the
innards; doesn't it make sense to use the same type of screw throughout?
My view has alayws been to keep the machine as original as possible. This
doesn't mean not repairing a machine, it doesn't mean not using modern
components for replacements. But it does IMHO mean not replacing
components unnecessarily. In particular, I always replace the minimum
number of parts (e.g. a chip and not the complete PCB), and not replacing
screws with different types.
I have a set of Bristol spline keys, so I don't really worry about this.
I also have Torx, Allen hex, System Zero, and so on... I've found just
about all of them necessary for classic computer repairs.
I would have hoped a museumwould also want to keep machines as original
as possible, but then again my views on Bletchley Park are well known...
If the bristol-type screws were used externally or in a prominent
position, or exclusively throughout the machine I think I'd agree with
you, but the requirement to have a special tool to get to the display
circuitry is long gone.
Well, I don't think a Bristol Spline key is any more special than, say, a
Torx driver...
Having said all that, I tend to take the same view as you when it comes
to my classic car, and try and use the right bolts / screws etc.
What have you got?
everywhere even if it's somewhere that can't
be seen - but then it
doesn't use oddball fastenings that not many people have the right tool
for :-)
Well, British classic cars tend to have Whitworth bolts all over them,
and not that many people have a reasonably complete set of Whitworth
spanners and sockets any more.
-tony