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CNC Lathe: Rack Mount PC
It's Daddy was a Slot Machine, It's Momma was a
Supercomputer...
I'm building an Athlon
64 system that goes in a rackmount enclosure to match the driver electronics
enclosure. I plan to keep the power switch as a slot machine switch (like
I used on the control panel) with the
label "Deal".
PC Specifications
The specifications for
the system are pretty straightforward:
| Motherboard |
ASUS K8V-MX Motherboard. Mini-ATX form factor. About
$60 when I bought mine from www.NewEgg.com. |
| CPU |
AMD Sempron 2600+. $56 from www.NewEgg.com. |
| Memory |
OCZ D400 2x512M RAM. $86 from www.NewEgg.com. |
| Video |
On board nVidia nForce 2 |
| DVD Drive |
DVD Drive, NEC ND-3550A $37.99 from www.NewEgg.com. Later on I swapped this to a laptop DVD drive and adapter in order to make more room in the case. Cost was somewhat higher. |
| Hard Disk |
WD 80GB HD. $48.50 from www.NewEgg.com. |
| Power Supply |
PSU Athena Power AP-MP4ATX35 Pwr Supply. $41.50 from
www.NewEgg.com. |
| Case |
19" rack mount enclosure purchased on eBay for
$80. I will use a second identical case to hold the driver
electronics for the motors. |
| Connections |
Monitor, keyboard, mouse, touch panel mouse, LAN, speakers.
I considered whether a USB key would be useful. A lot of CNC
systems use them these days to load programs onto the machine. They're
pretty cheap. The thing is, this machine will be sitting on my household
LAN, so I don't know that I'd ever use it. |
| Monitor |
Touch Panel screen. I have a 12" LCD touchpanel
I snagged on eBay for cheap. If I like the touch panel idea, I may
upgrade to a bigger screen later. |
| Keyboard |
I'll use some kind of pretty ordinary (and cheap) keyboard
that'll sit in a keyboard tray I got off eBay |
| Mouse |
Not sure I'll need a separate mouse with the touch panel.
We'll see. |
Total basic PC Cost, not
counting the enclosure: About $340, shipped, all new components. That
does not include a monitor, keyboard, or mouse, but it does get me a fast
64-bit system that is probably way over the heck to run Mach 3. You never
know, I may want to run Rhino 3D or OneCNC to make a quick change and
post new G-Code without having to run upstairs to the office computer.
Building the PC Enclosure
To create the square cutout
for the DVD I started out using my plasma cutter. It was better than trying
to cut out with a Dremel and abrasive wheel, but left a pretty messy edge.
The sweet ticket is to mill out any openings you can, and I did so on
my IH Mill. That leaves a really clean cut and straight lines. I bead
blasted the front panel to create a nice satin finish there. I mounted
one of my slot machine buttons (same as
used on the control panel) to use as a power switch for the PC as
well as a couple of LEDs to show that the PC power is on and a hard disk
activity indicator.

I cut the opening for the fan using my Phase II
Rotary Table on the mill...
To mount the motherboard
I used nylon standoffs of the kind that are readily available for such
purposes:

Nylon Motherboard Standoffs
While this
style is really designed to slide into sheet metal slots, I made do with
holes. Drill a 0.234" size "A" hole. Deburr the hole using
a Keo zero flute deburring bit (these work really nice!). You should be
able to push the standoffs through the holes with firm pressure as the
nylon has a little bit of give.
I must say
that the number of little holes, openings, brackets, and miscellaneous
finicky little wiring required to fabricate a PC cabinet from an enclosure
not set up for it is a little bit amazing. It's a very specialized world
and you forget how many little things come for free when you buy a finished
case from someone. For example, the little speaker that's needed to hear
beeps when you boot the machine. I never did find an Internet source for
them so I ripped one out of an old 486 Dell box that was sitting down
in the garage.
Here are some
photos of the finished PC after it first came up and I was installing
Windows XP on it:

It came up right away. Installing Windows XP here...

I like "Deal" being the power switch!

Pretty tight, but workable...

Rear panel. Cutouts were done on the mill...

Another view...
At this stage,
the PC could use some refinements. Not everything fit very well. In particular,
the depth of the rack mount chassis was not great enough to accomodate
the DVD drive without it protruding from the front or the hard disk rack
in the place where I wanted it. Other than that, it worked out pretty
well. When I get my sheet metal brake built, I might just re-engineer
a new case. For now, this is good enough.
I also need
to hook up the power and hard disk activity LEDs that are just taped off
at the moment. Lastly, the chassis fan is dying, and makes tons of bearing
noise. I scrounged it off my wife's computer. I had to give her the new
fan originally intended for this machine to keep the peace and just haven't
been back to Fry's to get another.
Software Configuration...
First thing's
first: installing Windows XP. This was followed shortly thereafter by the installation of Mach 3. I use a wireless LAN to go and retrieve the g-code files from my home office computer, which is where I run my CAD/CAM software.
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