Homebrew PCBs

Genaro,
       I have milled a couple of double sided PCBoards. I mounted
two steel pins in the bed of my mill. The two pins sit in the 
centerline of the PCBoard. One at the top and one at the bottom. I 
used paper instead of PCB material and a pencil lead instead of a 
milling bit. After drawing side one, I can then adjust the offset of 
the second side. Holding the paper up to the light I can check the 
alignment. When I am happy with the alignmet I replaced the pencil 
lead with a PCBoard milling bit and the paper with a piece of double 
sided PCBoard. I add two alignment holes to the center of the PCBoard 
that match the alignment pins. Make sure you leave room for the pins 
in your drawing!!! You can also use four pins, one in each corner. 
All my blank boards are 4" X 6"  If you use different size boards the 
process becomes more complicated. 

                                                        John 


--- In Homebrew_PCBs@yahoogroups.com, Jerry <gmanca101@y...> wrote:
> Hello, I was wondering if there is a technique to plot
> double sided pcb's with a plotter. I have an HP 7475A
> plotter that will never plot in alignment. Any
> suggestions would be appreciated! Thanks, Genaro M.