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

----- Original Message -----
From: "jerrytr2.com" <jerry@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, December 10, 2008 5:26 PM
Subject: [Homebrew_PCBs] How do you Drill Them?


> 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:

I normally use 0.7 mm or 0.8 mm drills for most component holes. I use
reduced-shank tungsten carbide drills with a Minicraft drill in a cheap
Minicraft drill stand. I have to be very careful when drilling FR4 material
(the drills break easily), but it's fine with FEC-1. I use resharpened
drills, they aren't very expensive, and are available from Mega Electronics.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller