Re: Up and Down; Is Z- away from the part or into the part?

Ken,

Yes, there are standards, but machine builders tend to make machines
to their own standards !!??

On a nornal CNC mill, Z zero is commonly the top of the material. Z
minus is into the material. Z positive above the material.

X and Y zero can be located anywhere within the range of travel.

There are several places on the Internet to learn more about CNC's.
Here is a good place to start:

http://www.mfg.mtu.edu/marc/primers/

Wayne