I have a brand-new Taig 2018CR-ER and after doing the disassambly-and-nut-adjust featured on Nick Carters Taig pages, I got my backlash to .002".
I typically mill symmetrical 1" mold cavities 1/4" deep in aluminum using a 1/32" ball cutter, and the backlash is not noticeable on my resulting parts.
Just the same, I tried using the backlash compensation available in Mach3 which
dropped the backlash to zero, but it added a crazy ramped decelerator when the axis changed direction, which tended to stall my steppers when used with my gcode and the acceleration I had set on my axes. I couldn't get rid of the funky behavior, so I abandoned the backlash compensation altogether.
It is kind of funny - my guage measures thous on a big dial, and a deflection of .002 looked HUGE on it. At first, I thought "Oh Noes!", but then I stopped and asked myself "Will, is it *really* that bad?". It wasn't.
