Question about Combining Z-axis with X-axis

I recently got into laser cutters/engravers. Every frame I have seen thus far only have X/Y-axis.
I'm trying to design a Z-axis that would sit on the X-axis, that would adjust the laser focus through a motor,
rather than having to manually adjust objects to the correct height.

Most frames (99.9% of them at least) have the X-axis moving up and down on the Z-axis.
I want to flip this. I want my Z-axis/frame moving on the X-axis.

The mounting plate for the X-axis is rather small, so using linear rails and wheels isn't that great an option.
I have considered building a custom plate, with straight gears on the left/right edges, then a motor could
simply lift/lower that plate with a gear wheel.

Any thoughts/ideas out there?

Edited 1 time(s). Last edit at 03/22/2017 02:13PM by Raestlin.

Just google "CNC mill frame" and you will get a million design ideas.

Also without seeing your frame its hard to give surgestions

Edited 1 time(s). Last edit at 03/23/2017 12:36AM by scottybfg.

Ask yourself, what are you trying to achieve by doing this? Laser cutter gantries want to be really light so they can move fast... If you move your Z axis at the same time you have to lug around a heavy motor that could easily double or triple the weight of the gantry.