Simple Rack and Pinion Zero Backlash (no springs)

[m_c]

The issue with most racks, is the teeth are rarely perfect for the entire length, especially once you get some wear, so you need some kind of sprung tensioning system to minimise backlash, while avoiding excessive binding.

The system here, once adjusted correctly will likely have enough spring due to the belt flex to deal with some backlash.
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However, you have to put things in context. If you want precision with minimal/no backlash, rack and pinion is not the ideal choice.