As other reviewers have noted, be prepared to spend 2-3 hours disassembling, degreasing, cleaning, lubricating, finishing, reassembling, and adjusting this product. It comes with heavy shipping grease and casting sand in every crevice. The Amazon listing should say ‘Frequently Bought Together’ with ‘WD-40 - 300349 Specialist Industrial-Strength Cleaner & Degreaser’, which I bought and used. This stuff is great and really works well to clean it up.It’s hard to believe these are actually new products. The handles had some sort of thread locker in the threads, and many parts appeared to have marks from use. I suspect they may be used surplus units.When reassembling, the acme followers can be tightened up considerably by shimming with aluminum foil so they fit much tighter in the slides. This will reduce a lot of backlash. The fit of the acme thread in the follower is actually quite good. One keyway was quite a bit too large which resulted in backlash in the handle. This can be shimmed with small gauge wire to some extent.The gibs need to be cleaned up with a file and fine sandpaper. Even after this, the slides do not move evenly and can have tight spots. I suspect more work to clean up the gibs and slides would help this.The locking nut on the handles can be adjusted carefully to remove most of the backlash in the acme screw bearings.My use was not for milling but for precision positioning for drilling holes. As long as you are careful to account for the backlash, it works quite well for this purpose and the holes came out very accurately. I can’t say how well it would work in a milling application (translation under side force).Although the handles imply 4mm per turn, for some reason actual measurements revealed that the acme screws are actually 2mm per turn, so you have to take that into account when making precision movements with the handles using the verniers.
Mike 
