Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hello,

My name is Jerry Kaidor. I've been messing with electronics for
many many years. Also put in a 20-year stint as a firmware developer.

The other day, I was doing a project with a PIC16F867A
microcontroller. Built up the circuit on one of those proto boards
that have a grid of three-hole lands. The resulting forest of little
green wires did not inspire confidence. Neither did the smoke that
came out when I powered it up :).

So I decided that a PCB would be more appropriate. Found this
group, read with interest about Toner Transfer. I had tried this
about 10 years ago, it didn't work at that time. Like many things,
the devil is in the details.

This time, armed with better info, I downloaded the expressPCB
software ( can't beat the price! ). I designed a one-sided board for
my project and printed it onto a sheet of Epson photo paper that I
had laying around. Found a gungy old piece of copper clad in the
garage, spent about a half hour cleaning it off with 000 steel wool,
paper towels, lacquer thinner, more paper towels, cosmetics buffs,
etc etc. Transferred the printout with my wife's clothes iron.
Wow! It came out perfect!

The only problem ( and I realized this unfortunately when it was
already mostly etched ) was that it was mirror imaged. I had used a
function in my printer setup that causes the printer to print mirror-
imaged - but apparently it wasn't needed. Grrr! OK, I'd just
solder all the parts on the top :). Or just do it again...

To play with the process, I started drilling holes. Hit a snag.
My smallest "ordinary" drill bit was a #60. It was just too big. I
also had some little tiny PCB drills that I got at the ham swap some
years ago. Too small! (.8mm, I think )Also, chucked in my giant
tabletop drill press, the tiny bit only lasted three holes before
breaking.

So - how does one drill these holes? I'll pick up an assortment
of PCB drill bits today, but I don't think my giant drill press is
going to work. Alternatives I see:

∗ Jameco lists a little drill and press for about $60.
∗ There is a Dremel drill press accessory for about $50.
∗ I have a Sherline milling machine. Sherline lists a "sensitive
drilling attachment" that chucks into the mill. Basically,
the mill only drives and holds the attachment - you move it up
and down via a knurled ring. This really looks like a hot setup, but
it's not cheap - $110.

- Jerry Kaidor