Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "ben_englund" 
<ben_englund@t...> wrote:
> I am in the process of making a cnc pcb engraver and it seems like 
> the hard part is the designing.   > 
 
Ben:  I have a time with PHOTOS on these home-brew sites!  This one 
doesn't like photos in the PHOTOS section, rather have them in the 
FILES section.  I won't go into the thinking, there.

Look in the FILES section for "Homebrew Equipment...", and click on 
that.  Then look for a file named DSCN0329, and click on that.  That 
will give you the photo of my PET-controlled PCB-drill/engraver.  The 
basic chassis is Baltic birch ply, precision cabinet-work.  The white 
surface is Formica.  The quill is a 92W (aircraft instrument) 400 Hz. 
3-phase motor in a "servo casing", and I designed a 400 Hz. generator 
circuit to power that.  Turns "synchronized" 12,000 RPM.  So, will 
punch up to 0.1" dia. carbide bits merrily into one layer of FR-4 at 
a rate of about 1 hole per second, when within, say, 0.1" spacing.  A 
bit longer per-hole when 1" or more apart, of course!  It was an 
excellent learning experience, and still works, but PET is dying, so 
I will have to convert to PC use, soon!  (will use old laptop for 
that!)