Those file URLs with long strings of apparently random characters are temporary and disappear after a few seconds to a few minutes.
The file in in the group's files section: <
http://tech.groups.yahoo.com/group/Homebrew_PCBs/files/> top drill-bottom view drill press.pdf (yet another good example for naming files without spaces in them.)
Donald.
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----- Original Message -----
> From: "Charles R. Patton" <charles.r.patton@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Monday, April 16, 2012 8:29:43 PM
> Subject: Re: [Homebrew_PCBs] PCB Drilling Viewer
> I described setting up a web cam to view the bottom side of the PCB
> while drilling from the top side. I use a sacrificial piece of plastic
> that I drill first so it indicates exactly where the drill is hitting.
> That eliminates a host of problems such as boresight error.
> Please see:
> http://tech.dir.groups.yahoo.com/group/Homebrew_PCBs/message/28429
> and I put pictures in
> top drill-bottom view drill press.pdf
> <http://f1.grp.yahoofs.com/v1/gLKMT4q13XDxiIgzZmifkT0BbqsHILZSk-F9mp_Cbr7hpFKpq63z_9WqZR4coro9pOPQAfkru-t0SpL73lbMtWYcu0eHtV598w/top%20drill-bottom%20view%20drill%20press.pdf>
> in the files section.
>
> On 4/16/2012 3:39 PM, Simao Cardoso wrote:
> >
> > bebx2000 wrote:
> > >
> > > Could anyone offer an opinion on this drilling fixture?
> >
> > Hi, i remember some old discussions on this list about a drill press
> > that I could never understand how it works, until saw that image. I
> > tried to search the thread but i lack time right know.
> >
> > If i understand it right, and in my modest opinion, it intends to
> > drill
> > the single sided board from the non copper side, because the drill
> > bit
> > tends to slide if drilled from the copper (if it hasn't a etch hole
> > for
> > drilling) and avoids the annoying burrs on copper. It has a light to
> > illuminate the bottom side of the board and when it cross the glass
> > it
> > will behave like a mirror to your point of view, because it has more
> > light from the other side, and you see the down side of the pcb with
> > the
> > alignment hole. There are who adds a mirror so you can see the
> > bottom of
> > the pcb from above, in a comfortable position.
> >
> > But i, before the cnc, just bought a proxxon drill stand and both a
> > collet chuck proxxon spindle for carbide bits and another with 3 jaw
> > keyless chuck from proxxon too for hss and other tools. All the
> > pcb's i
> > hand drilled had the etched hole, never went through this.
> >
> >
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>