Z axis backlash

[maxxdog21]

I just noticed that when I engage the fine adjust on the Z axis, the knob turns over one full turn before the head starts to move. I would like to get rid of this "slop". Does anyone have any ideas? I was thinking that I could put a shim behind the "rack" that is mounted on the column. This would move it out and make it tighter on the "pinion". Am I on the right track with this thought? And help would be great!

[maxxdog21]

I put a .009 shim behind the rack and it helped a little. When I took the fine control off the machine, I found a worm and worm/gear setup. It seems that quite a bit of the slop is coming from this assembly. Is there a way to tighten this up?

[MNoble]

I too was trying to figure a good way to limit the slop in the rack. After reading a few other folks attempts at this i decided to scrap it all together. I removed the rack, gear, handle and fine adj. I then got on ebay and started looking to ball screws. I found a 14" ground with nut for something like 40 bucks. I then machined a couple bearing blocks mounted them to the side of the column and it it working very well. I am pleased with it. Now the Stepper is mounted on the top of them machine and not stichin out the front.

Mike