[Beowulf] A Cluster of Motherboard.

Glen Gardner Glen.Gardner at verizon.net
Fri Nov 11 08:09:16 EST 2005


I find it unacceptable to think that a machine shop is unable to make
components to specifications.  I have worked in an engineering
environment at all levels over the years and have had few problems with
components being fabricated incorrectly.  As a rule,it is known how to
do this stuff, and it is not exactly rocket science. Most small machine
shops are well enough equipped that they can literally fabricate
components for use in spaceflight (been there, done that). Cutting and
drilling sheet metal to a drawing is not exactly a daunting, nor
expensive task for them.  

I do my own sheet metal work. Mostly because I know how and can cut out
the middle man and save even more time and money.  

I simply do not see why this should be such a daunting task.  If people
cant manage to use a pencil , hacksaw and a drill to make simple things
then they might be better off buying commercially made hardware all the
way and forget doing anything new and different... for the most part, I
think that people have sufficient skill to handle the task.

The cost savings is there, and the advantages are significant... of
course this is why people do sometimes stack bare boards to build
clusters.

Glen


On Thu, 2005-11-10 at 21:22 -0800, Alvin Oga wrote:
> hi ya
> 
> On Thu, 10 Nov 2005, Jim Lux wrote:
> 
> > Uhh.. thermal management for large systems can be a lot more complex than 
> > just pushing bucketloads of air through.  Ask the folks designing blade 
> > systems.
> 
> seems to be an ongoing issue .. but that is where all the fun is
> to have the cpu running lower than other equivalent boxes
>  
> > >The cost of an aluminum plate and standoffs is trivial compared to a
> > >case,
> 
> standoffs is about $0.01 - $0.02 each ... 
> - you'll need say 4-6-9 of um for your motherboard ( a whole $0.10 :-)
> 
> but the purchasing dept that has to place that order for 10 standoffs
> is gonna cost a mint, say 10-15 minutes of phone call time and chatting
> about the in-laws so that the next time they call, they can also talk
> person-to-person instead of voicemail and crossing ones fingers for a
> return call
> 
> and we must not forget the $0.03 motherboard screws too :-)
> 
> > and once you have made one plate all the others can be readily
> > >mass produced using a template and a hand drill.
> 
> alum plate is not much more expensive ... i hear numbers like $0.30/lb
> of blank steel .. but you do have to buy it by the lb, say 4'x8' blanks
> and have the "million dolar equipement" to cut and bend it into shape
>  
> > The material cost may be low, but you're not going to be out making 90 odd 
> > aluminum plates with a hand drill (I assume you're talking an electric 
> > drill, not an "eggbeater"), unless you're not very picky about tolerances 
> > and fit.
> 
> some folks are more sophisticated ... using dremel ... or tools from
> ace/orchard ...
> 
> > >I can fabricate a chassis for a mini itx cluster from aluminum plate and
> > >aluminum angle stock with simple hand tools in about 2 days....
> 
> it should be about 5 minutes .. after finding the x-y coordinates
> of the holes, assuming its just a flat metal and no cutouts
> for the i/o brackets
> 
> > and I
> > >could do it in hours if I owned a drill press and cutoff saw.
> > >The main point is, it can be done cheaply and with simple tools.
> 
> unfortunately... its NOT that simple or realistic ...
> 
> and more importantly.. repeatable
> 
> > Yes, but if you pay yourself any sort of reasonable rate, it's not 
> > necessarily cheaper, especially when you consider assembly time.
> 
> it 10x - 100x costs more in labor costs to:
> 	- find the store to sell the metal
> 	- find the purchasing folks to place the order
> 	- find the folks to get quotes
> 	- get the approval to place the order 
> 	- receive the parts
> 	- get the parts from shipping/receiveing onto your desk
> 	- .. endless list ..
> 
> 	and since its not being shipped anywhere, we won't have to
> 	buy $2.oo cardboard boxes and $15 foam for shipping
> 	and all that handling and paperwork and christmas wrappings
> 
> > 2 days of hiring someone basically competent is probably about $500.
> 
> to get it done right ... it's more like $1,000/day ... and about 2-3 days
> to get drawings that is usable by the machine shops 
> 	- cheaper labor will not always work better in the long run
> 	so we've decided to pay the good boyz the extra $$$ to get the
> 	stuff done right the first time .. and not worry about the
> 	1mon - 3mon delays due to screw ups with drawings by the 
> 	inexperienced "chassis" or sheet metal autocad'erz
> 
> 	- anybody can draw lines and circles and bend here and bend there
> 	but it does NOT mean the machine shop can build it per drawing
> 	or that the system will work efficiently when it's on 24x7
> 
> 	- say, 80% of the drawings are wrong and has to have followup
> 	phone calls to fix the drawings
> 
> 
> fun stuff .. to get it done right ...
> 
> c ya
> alvin
> 
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