Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
-snip-
> I have seen solid-carbide "router bits" in various mail-order
catalogs, but 
> never having used them continuously every day, just buying a few "to
have on 
> hand if ever needed", I can't now tell you from whence!  Check
catalogs of 
> MPJA, JDR Microdevices, Enco, Harbor Freight, and of course, those I
have 
> forgotten at the moment!

Don't forget to check the Links section of the list, and if you have a
good supplier please add their website in the appropriate folder.

-snip-
> It almost seems that some "ol' boy out there" in the
machine-manufacturing 
> business might do well to design/offer a neat little 100-W.
air-motor with 
> air-bearings, a 1/8" collet, and a design-RPM of, what, 100,000 RPM,
running 
> on 90 PSI, 4 CFM "shop air" for $100 each, not including compressor!
   (is 
> 90 PSI @ 4 CFM about equal to 100 Watt????)

Don Lancaster suggested dental turbines as cheap (about $14)
disposable cutting tools. Something I've wanted to try. Also called a
"Dental Handpiece".

http://63.140.207.28/musev.pdf/hack76.pdf

With a suitably sharp bit, one of these on a very flexible airhose,
and a heck of a vacuuming system, these may work on something like HP
flatbed plotters. Maybe have to stick with 1 oz or 1/2 oz copper. I
have no idea what the runout is on these little turbines. It should be
pretty low, as any vibration while carving up teeth is -highly-
undesirable.

Here's his page on what he calles "flutterwumpers", ie, hack and grind
plotters:
http://www.tinaja.com/flut01.asp

Has anyone done any more investigation on using John Kleinbauer's
Scratch 'N Etch idea? For those that weren't here then:

Spray PCB with Layout Fluid (Dykem brand was suggested) with a thin
even coat.

Place modified pen in plotter- it has a carbide tip in place of the
pen tip.

Plot PCB pattern onto board. It scratches off a thin line of the
layout fluid.

Etch and drill.

Denny did a couple of tests by hand, here are the archived messages:
http://groups.yahoo.com/group/Homebrew_PCBs/message/281
http://groups.yahoo.com/group/Homebrew_PCBs/message/286

I've modified a pen and bought an HP plotter just for this, even have
a spray can of layout fluid. Just have had way too much to do.

Steve Greenfield