Hey, first post, so I'll try and make it decent.
After a week of researching around the web, trolling these forums, and generally just reading, I've come down to a split.
I've built two "bash together" CNC's at this point, my latest running X Y and Z and cutting MDF decently with almost no backlash.

Is it viable to build a CNC router for copper work?

Built sturdy enough obviously, and provided that the copper is either kept cool via an air jet, vortex tube, or oil flow, could a router motor be viably able to "mill" copper. Obviously versus a milling machine there is a number of drawbacks and limits in capability. But if your designs are to be made in a flat stock/bar of copper, and need only one side be cut into, can it be done?

If anyone has a project log or link it would be tremendously helpful, I'm mainly trying to figure out what sort of motor assembly I'd need.

yeah copper will cut as easily as aluminium so look around for some rigidly built routers
most people here look to be able to mill ali
so you should be looking for a machine made of ali

i happen to be looking for people to make the machine i've made
which is a fixed-gantry router with unsupported rails ,it was an affordable option for me but i'll let you make up your mind

it was made from this pattern
92691
92692

i had to get a machine shop to mill out the ali
and even then it required a bit of work to put together

if your looking for a real spindle motor
then the serious amongst us are drooling over the chinese spindles controlled by vfd

we've tried copper with our 4x8 30,000 variable router.......no luck. Maybe with an actual spindle things would be different.

Hope that helps ya
Mike

Yes, it's very doable. Check out this build. http://www.cnczone.com/forums/showthread.php?t=32609 He can mill steel.

milling copper and steel can easily be done with a router , mine runs at 25000 rpm and I didn't have any problem cutting steel with a 1/2" bit , its all in the approach , I've got a video in the following link where half way thru the vid i bump it up to 120ipm http://www.cnczone.com/forums/showthread.php?t=23120&page=13
milling copper at this speed may be a bit trickier than steel simply because its so gummy but if you cut it in a way that you won't have a melt down then you should be alright with the right setup

Yes routering copper would be very similar to aluminum. I use Belyin-Y spiral carbide bits with windex or WD40 coolant. My machine is based on the DataCut plans (google them) and I use a Chinese VFD spindle.

Analogman, Could you tell me what is a "Chinese VFD Spindle" ? and where can we buy this part?

Analogman, Could you tell me what is a "Chinese VFD Spindle" ? and where can we buy this part?

Ebay.

http://cgi.ebay.com/WATER-COOLE-MOTOR-SPINDLE-2-2KW-AND-MATCHING-INVERTER-m_W0QQitemZ370271882330QQcmdZViewItemQQptZUK_BOI_Industrial_Automation_Control_ET?hash=item5635ec8c5a

Thank you Ger21 for the info. Really the price is low compared to other supplier.