Gantry to bed height.

[routerdriver]

I suggest you draw a line from the tip of your tool to the corner of the Z axis plate.This may illustrate the limitation you can encounter with taller workpieces-you can't get down the side of them.Its equivalent to what off roaders call approach angle.Won't be a problem if you intend to work on items in a vice but it looks like the design features a larger working area than just a vice would require.

I appreciate that isn't a totally finished design,but I can't quite understand which parts of the Z axis are moving as the mounting plate for the stepper sits on top of the Z axis backplate and no slots are visible.Will there be ballscrews or timing belts on the X and Y axis?One point to note is that if you go along with the sound suggestion of increasing the width of the Z axis to 200mm you will have a region of 100+mm either side of the machine that can't be accessed so make sure that the width is sufficient for the biggest part you are likely to be working with.