Re: [CAD_CAM_EDM_DRO] Re: DIY probing

> Hi Chris,
>
> I could TOTALLY see moving the probe into the approximate center of the
> horn's bell, and then determining the center and diameter, or "walking"
> down the sides. Do you assume it's symmetric? Do you digitize circles
> at various depths? Do you "walk down a side, rotate around the circle a
> defined amount (angle), and then do another walk down the side? Or
> combinations of the above?? Lottsa interesting movements!

As I'm trying to measure antiques, I have to assume that the bells
will be somewhat oval in shape and probably have dents. I'm also
assuming that they won't be perfectly centered on the machine and
their axis will be skewed from teh machine Z axis if it is even self
consistent. I originally thought of a rotary machine, but realized
that I would need to align the probe carefully, wheras with a
cartesian setup a bent probe simply makes the whole object seem
shifted a little bit in position - it still gets measured accurately.

I would like to be able to generate cleaned up shapes using both an
equal area symmetric shape (which should reproduce acoustic properties
of the instrument's current condition) and/or equal perimeter (which
would yield the shape before any ovaling).

The resulting data could be used to compare horns from different
makers, regions, time periods, etc. But the primary purpose is to
produce G-code to turn a mandrel for making reproductions of these
historic instruments. About 70-100 lbs of cast iron and
steel... really worth getting the shape right before I start cutting.

Do you have a test indicator you could run next to the MAXCNC
digitizer while hand cranking the mill, in order to determine its
repeatability? I'd be very interested in the results of any test you
could run.

Chris