Expected precision from acme thread????

I just spoke with (the owner I believe at) Gecko Drives, and discussed linear encoders and such, in connection with closed loop servo control. I was very disappointed to hear that using a linear encoder to alleviate backlash problems will not work well. He indicated that the inertia and hunting that will go on with using servos in closed loop with linear encoders, jumping between the ends of the backlash, make this an undesirable approach. Has anybody got some real life experience as to what effective precision one can attain when keeping the old acme threads, IF THEY ARE NEARLY BACKLASH FREE? My full size milling machine is in great shape for a WWII vintage Van Norman, and I was able to get the backlash adjusted out to nearly zero. Of course the effort required to turn the screw nearer the ends of the table travel are greater naturally due to lesser wear. Am I taking a poor approach in leaving these in? What expectation of precision can I expect?
Thanks for the input.

Bill Kichman
103 Old Furnace Road
Cornwall, PA 17016-0643
tel/fax 717/270-0714


[Non-text portions of this message have been removed]