Shoddy Hardware (Was: Re: WW fixtures (was Re: "New" PDP-8))

From: jpero_at_sympatico.ca <(jpero_at_sympatico.ca)>
Date: Mon Apr 1 13:33:55 2002

> Speaking of machined parts versus something else...
>
> Anyone notice how commodity PCs have screws that have clearly
> been *cast* onstead of *turned/Machined*? Everytime you thread
> one into a hole, you generate a nice supply of metal shavings.
>
> Not good.

Just bad bag of that screws. Toss it and buy bag of decent screws.

If find a peecee screw that is still chewing or "seizing up" touch
bit of oil to the thread. Fixed for good.

This happens because of poor lubing or nothing or low quality steel
in production of those crappy fasteners. Those that makes shavings
is because of cracks in the thread tips. Almost all screws, bolts
are smashed on one end of cut rods to make heads slots, philips, hex,
torx etc, rolled in thread dies to form threads. Very few uses true
machined fasteners. Quality smooshed on heads and rolled fasteners
are *stronger* because of compressed grain. Machining process cuts
into this grain and introduces crack stress beause of too sharp
corners. I know because machined fasteners were used frequently in
clocks and watches. Yes I did break machined screws for any reason
not just from over-tightening.

Machined are very sharp corners, ground-look. Rolled and squished
heads looks well that, smooth or dull and look at ends of these
fasteners is convex.

> To get back on topic, when did this trend start? The IBM PC,
> PC/XT, and PC/AT used machined/turned fasteners. Lots of classic
> non-consumer hardware used various "captive mechanisms" instead
> of plain old screws and bolts.

Actually not. IBM used mass-produced rolled screws of good quality
and early machines did use mass-produced fasteners that were good
quality.
 
> And how about sharp edges inside a chassis? Older hardware tends
> to have spent a little time in the hands of a whitesmith, who
> added lots of finishing detail like smooth edges that don't cut.
>
> -dq

Yes, *can* still buy decent peecee cases made with rolled
edges. Acer is one, Antec is another so on.
Aluminum cases is making slow coming back. I know classic 'puters
were made in large numbers with aluminum cases early days.

Cheers,

Wizard
Received on Mon Apr 01 2002 - 13:33:55 BST