Z-axis relative to worktop in Easel

I’ve been watching some YouTube videos by CNCnutz (Peter Passuello). He sometimes uses a technique to zero his Z-axis that is relative to the work surface, not the workpiece surface. He does this by entering a negative number for thickness. This ensures that a certain amount of the workpiece remains, such as for surfacing. Is this possible with Easel?

A quick test of Easel shows that doesn’t seem possible…

However, here is what I do if I need critical measurements are from the bottom of the stock (work surface top).

  1. I do like mentioned above; I zero to my wasteboard.
  2. Move the Z-Axis to my programmed stock thickness
  3. Manually turn on my spindle
  4. Only move the X & Y and zero it into the bottom left corner of my stock, cutting into the stock if need be.
    This can probably be done through manual GCodes, but I just do it this way when needed.

It’s useful when I have a bunch of parts to make, where the stock material is not 100% exact same thickness.
This way I know the stock will be cut all the way through, and no danger of cutting to my wasteboard.