Homebrew PCBs

>       Ed Okerson wrote:
>  >> Maybe but its a matter of pure luck that any given person comes across
>  >> one of these small drill machines your talking about. And spending
>  >> $1000's on a brand new drill machine is just not an option. Building a
>  >> CNC machine from scratch is a mammoth task compared, to building a
>  >> manual drill press.
>  >
>  >
>  > That is simply not true.  I built a CNC mill/drill based on the Brute
>  > design at www.crankorgan.com and it only took about a week to make it.
>  > Granted it is not a professional unit, but it is accurate down to
>  > 0.00025", plenty good enough for hobby PCB drilling!  It cost
> virtually
>  > nothing to build, mostly scrap aluminum channel and scrap plastic
> blocks.
>  >
>  > Ed Okerson
>  >
>
>  They look interesting, but what is used as the linear slides ? How are
>  they attached to the U channel ?
>  Is the lead screw standard zinc steel threaded bar or is it  the true
>  thing ?
>  It looks like X, Y and Z axis are identically built, with only the
>  length of the Z axis being smaller.
>  What CNC software are you using ? Did that take a week to write too ?
>  And most important, what is the minimum tooling required to build one of
>  these ?

The linear slides are just blocks of high density plastic cut to ride
inside the lip on the aluminum channel.  I used 1/4 20tpi stainless steel
threaded rod for the lead screws on mine.  For software I am using EMC
from www.linuxcnc.org to run the machine, and I do PCB layout with Eagle. 
I am still in the early stages of getting this all working, and my spare
time is very limited, but I built that machine the week of Thanksgiving
when I was off work.

As for minimum tooling, not much.  I used a skil saw to cut the plastic
and aluminum, although a table saw would be better if you have one, but it
could also be done with a hand saw if needed.  Also a drill to make all
the holes for mounting screws.  I did make some custom fittings to center
the threaded rod in the bearings with a lathe, but that is really not
necessary.

If you are not inventive, then I would recommend ordering the plans for
$35, but I built mine just from looking at the pictures on the web site.

Ed Okerson