Homebrew PCBs

In a message dated 3/24/2004 4:16:07 PM Central Standard Time, 
stefan_trethan@... writes:
However i still don't see the advantage - with manual drilling it is not 
easier to drill first, i would say it is even harder as you have to aim with the 
same precision and you have no guiding hole.<<
ST:  With the HOLES there, you can "spin" a felt-tip (Staedtler Lumocolor 313 
red) in the holes, making a PERFECTLY-concentric resist-pad.  

For the infrequent tiny little board with, say, no more than ONE IC and three 
resistors, four terminal-pins, and one tiny capacitor, I will often use 
double-stick tape and stick the layout-drawing (done on 0.1" grid "graph paper") 
right to the copper.  Then the drilling is easy.  Particularly if you use a BP 
mill with a chuck for the drill-bit in the quill, and use the index-wheels on 
the X- and Y handwheels.  The "drawing" and adhesive will peel right off, 
pulling SOME of the dirt on the copper off with it, and then some light sanding 
with 240 or 400 grit emery, wash, and . . .

I put a photo of my home-brew CNC PCB drill in the "photos" section (Nr. 15), 
entitled "Home-Brew CNC PCB Drill".  Using that (back when the PET was still 
living!), I could REPEAT drill-patterns as accurately as "store-bought"!  


[Non-text portions of this message have been removed]