Homebrew PCBs

Hi John,

Where do you get the PVC, other then a "plastics" store?  Anything I
missed?  I think there is a TAP plastics in San Jose, CA.  

The 'L' picks up two edges of the PCB?  Do you flycut the PVC flat
first? should true it up.  

I have a 60 degree engraving bit that was recommended to me.  

Yeah, getting two traces between pads is a little hard to achieve!  I'll
settle for a single trace.  I've seen their sample boards, really nice.

Are you saying that they use thinner copper or a special board for
mechanical etching?  I hadn't heard that.  

Alan  KM6VV

crankorgan wrote:
> 
> Hi Alan,
>         I mount a 8" X 8" piece of 1/4" PVC to my bed
> using four flat head 10-32 bolts. I run the machine with
> an old Mechanical Etching bit in it. I cut a fine "L" in
> the plastic. In the "L" I drill and tap 2-56 bolt holes.
> I then place a PCB under the bolt heads. This helps me
> locate where the other screws go.
>         The board is held down on all sides with just the
> bolt heads. If you use a 60 degree Mechanical Etching bit
> variations in copper and board will not be a problem. This
> is if the board is cuped up! The single sided ones I buy
> are.
>        My machine will do a trace between a pad. Two traces
> between a pad!!! No way! I have seen the sample boards on
> those site. Show me the boards made by regular people using
> their machine. No burrs either, just perfect traces.
>        The boards I use have very thick copper. If I get
> the money, I will try some PCB made for Mechanical Etching.
> 
>                                             John
> 
> --- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi John,
> >
> > Good tips!  When you bolt your boards down, how much deviation is
> left?
> > I just looked at LPKF (again, for the 1000th time), and they are
> VERY
> > precise!  TWO traces between pads.  And I'm thinking that if the
> depth
> > is controlled more closely, bit life will be improved.
> >
> > Alan  KM6VV
> >
> >
> > crankorgan wrote:
> > >
> > > Hi Alan,
> > >         I see that!  I use the heads of 2-56 bolts to hold
> > > my boards down. The ones I buy are cuped foil side up. They
> > > are 4" X 6". The bolts go into a piece of 1/4" PVC. I find
> > > holding the board by the edge-the best method so far. Since
> > > all my boards are 4" X 6" I only have to take two bolts out
> > > and the board slides out the end. The bolts pull the board
> > > down flat. When I do smaller boards, I have other rows of
> > > taped holes in the PVC. The Tit4Tat board was 1/2 of the
> > > 4" X 6" board. I would make two at once. I used to make 4
> > > 1 axis boards out of one 4" X 6". Tape is fine for doing
> > > a flat pcb, but most surplus boards come warped.
> > >          How would I fix a warped board when making a double
> > > sided board? Simple, use one or two bolts in the middle of the
> blank.
> > > They then become mounting holes.
> > >
> > >                                       John
> > >
> > > --- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...>
> wrote:
> > > > Hi Listies,
> > > >
> > > > Some activity on the CCED list about LPKF and holding PCB's
> down to
> > > mill
> > > > them.  Anyone here have the LPKF system?
> > > >
> > > >
> http://www.lpkfusa.com/products/product/rapidpcbpro/index.htm
> > > >
> > > > I'd like to get a closer view of the Z height "tracking donut"
> on
> > > this
> > > > machine.  And, I'm in the process of downloading a demo of their
> > > > program.
> > > >
> > > > Alan  KM6VV
> > > > P.S. I'm also looking at a low-cost Gerber to Gcode translation
> > > program
> > > > that should be available soon!  More details when past beta.
> > >
> 
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