Dear Alex & All,
I have not read much on this thread so if someone has already talked
about this please forgive me.
About three years ago I took a year off of teaching for a sabbatical
to learn more about CAD CAM. I entered a totally new field with a lot
of metric measurements in my head. One of the tool & die instructors
explained a good lesson about measuring to me. Picking up a digital
caliper he measured a part. He showed the length in inches and in
millimeter. The inches had a much more precise measurement. In fact
the parts we had to make had a tolerance of plus or minus .002 of an
inch. There were no available tools or machines (lathes or mills)to
give me a metric equivalent. If any of you have a digital caliper
take a measure a part and go back and forth with the conversion
button and you will see. The metric just measured to .00 of a
millimeter. He even further informed me that when many parts are
drawn the tolerance is .0005 of an inch is requested. Now I realize
many parts do not need that level of tolerance, however with machine
tooled parts coming from all over the world the inch measurement will
be hard to eliminate. Many international sources make American
machine tool parts and the parts are requested in inches.
With CAD CAM entering our jewelry world I would be surprised to see
the metric system change what has already been established in inches.
In my own shop I would love to stay metric for the CAD CAM but the
machines I use are all in inches. I will be posting some more CAD CAM
pieces I made shortly on the gallery.
TR the Teacher