AW: PCB making tips

[R.G. Keen]

>Use a layout program that doesn't fill the "eyes" where the
>holes will be, i.e. the copper must be etched away where the
>drill will go thru. This will give a perfect guide for the drill, and
>no drill press or microscope is needed. 
I use Easytrax (free) and used to do this. It works well enough. Not
as quick as a drill microscope or as precise, but it does work. The 
difference, I think, is that I use 0.062" pads and 0.028" holes in
a 0.062" pad leaves only a few thousandths of an inch for error. 
With bigger pads, sure, hand drill. I regularly use one line between 
IC pads with PNP blue, and sometimes use 0.050" pads for transistors, 
and all resistors stacked on 0.100" centers as well, so the extra 
precision in centering holes in pads is worth it to me.

>Drill free hand with
>one of these little machines that are significantly smaller
>than a dremel. With this method I can produce approximately
>one hole per second - I think it's rather fast. Of course there has to
>be a little rest every 20 or 30 holes, to let the machine cool down,
>and to relax your wrist, so in the end its rather 30 holes per minute.
>Still not bad, I think. For this method it's important that you use
>the cheap pcb material, not the more expensive and much harder 
>epoxy. With the cheap pcb material, you can use cheap drills
>(no hard metal).
You have a good point - I use glass-epoxy, and steel drills only
last about 100 holes before getting too dull. If you can use carbide, 
you get several thousand holes per drill, and it's like dropping the
drill bit into yogurt it cuts so fast. With paper-epoxy or phenolic
board stock, the steel drills last longer. When they dull, they
start raising a lip around the holes.