Rack and Pinion..... HELP NEEDED PLEASE
Hello there,
I have started building my own CNC router and had a few questions about the drive for the long Y axis. I have decided on a rack and pinion system for driving the axis but wondered if the pinion needs to be spring loaded onto the pinion. I have looked at many homemade and kit built machines, these all seem to have the stepper motor on some sort of adjustable tensioner or spring to keep the pinion on the rack. Would it be better to have the motor fixed solid to the frame using a suitable shim to give a minimal amount of clearance between the rack and pinion? The only reason i can see for having a tensioner is if the rack itself is not completely straight and the tensioner would 'iron' out any of these disscrepensies. Is this correct or am i missing something obvious?
Thanks for your help peoples.
Dave