Re: post #7 -- The problem with using a constant load to compensate for backlash is the anti-backlash load has to be greater than any load the router will experience. In wood cutting for example, the spring or weight load may work fine until the bit encounters a course wood grain, then the wood's resistance will over-power the spring/weight and ...... backlash.
If the weight is increased to counter all potential backlash inducing loads then the motors will be working to their limit every time they move against the weight.
Hey, Chuck Knight! Excellent FAQ!! Thanks!!