Wood Gear Prototype

I'm interested in making a all wood adjustable height desk. I've been debating how to design it and decided to prototype a gear driven approach.
The plan is to have the gear reduction on one side of the desk and a rack on both sides driven by a common shaft. Avid made plans for a version of a lifting desk, but they use expensive linear rails which I wanted to avoid.
Next step is to figure out a good locking mechanism.