Re: Leadscrews, PCB router experiment, Gerber

Hi Bob,

What program are you running to generate the board layout, Gerber files,
and read/convert to Gcode? I couldn't test Gerber read in KellyKAM
demo.

The ME08 bits look good, I just wish I could buy less at a time! $50
minimum! Are you using a Dremel tool? I'd like to hear more about your
setup and process!

How wide an isolation cut do you get with the 60 degree bits? I'd also
be interested in examining a set of Gerber and Excellon files for some
little board, if you don't mind.

Alan KM6VV

cncdxf@... wrote:

>
> Hi,
> I just tested the 60 degree mechanical etching bits from
> Think and Tinker. They are micro grain carbide, and they stick
> to a magnet. T&T told me to use 30,000 RPM at 16" per minute
> when milling. I am running the bits at about 8,000 RPM with
> a feedrate of 5" per minute. My boards take around an hour to
> cut at that rate. For wider isolation paths a carbide drill bit
> is a cheaper option. I do IC boards. This is Kleinbauer's
> method. He also told me to coat the board with motor oil before
> milling. I find this keeps the dust down.
>
> Bob
>
> --- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> > JanRwl@A... wrote:
> >
> > > In a message dated 24-Jul-01 02:21:40 Central Daylight Time,
> > > elson@p... writes:
> > >
> > > > The experts can tap the shank on their fingernail and listen
> for the ringing
> > > > of the cantilevered drill bit. If it rings with a very high
> pitch, close to
> > > > 10 KHz, then it is carbide for sure. HSS is magnetic, of
> course, but some
> > > > other cutter steels are not.
> > > >
> > >
> > > The most OBVIOUS way to tell "in an instant" is to "weigh" the
> piece in your
> > > delicate fingers! If it is OBVIOUSLY heavier than steel --- like
> LEAD would
> > > be, only even heavier, yet! --- it is solid-carbide! Dull grey,
> not shiny,
> > > like HSS.
> >
> > Unfortunately, the drill bits in question are quite small, and the
> shanks are
> > often HSS or similar material, so the tiny drill bit's weight is
> lost in all
> > that.
> >
> > > Carbide is even MORE magnetic than HSS!!! NOT a useful test!
> >
> > I find this hard to believe. At least, PURE WC (Tungsten Carbide)
> is not
> > magnetic at all. The various commercial formulations often have
> large
> > amounts of Cobalt and other magnetic metals alloyed in them, which
> makes
> > them mildly magnetic. I just went into my shop to check this, and
> found
> > most of my "solid carbide" tools to be very slightly magnetic,
> although the
> > shanks of many of them were much more strongly magnetic than the
> > cutting end. I didn't fina any where the cutting end was strongly
> magnetic
> > at all, but the HSS tools definitely were.
> >
> > Jon
>
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