I really like this z axis indicator  http://www.thingiverse.com/thing:920819I want to make similar one that can hold dial gauge instead of digital gauge. Since thoxbui posted only stl file, I had to design my own in openscad. X-rods spacing is 45 mm. Rods are of 8 mm diameter. You can utilise my scad file and put any probe mount on it.