It looks like I'm one of the fortunate ones. All parts arrived even though the box had a bit of an opening in it from shipping damage. My main issue is that they don't package this set appropriately. It should be double boxed to ensure everything arrives and arrives undamaged and no parts fall out.I am using this set to expand the Y axis of my home built CNC. I have assembled everything just to test fit and it seems to have very little, if any slop/backlash. I'm pleased and I feel fortunate that I got all of the parts and they seem to be precisely machined.The price is fantastic for the quality I received. The blocks and rails are 5 star. I deducted a star for inadequate protection of the contents.At some point you'll probably be trying to mount this to something... or something to it... or both. The threads are 5mm - 0.8 for the blocks and ball screw mount. The through hole in the rails is about 6mm but the two different 6mm machine screws I tried have a head too big to fit the counter sunk hole. I'm hoping to find a 6mm machine screw with a small head, if not, I'll use the grinder or have to revert to 5mm screws to mount the rails.
Jim Jackson 
