As expected, doing the Y stage goes a lot faster, now that I've done the X stage. In less than an hour of work, I cut, sanded, teflonized and mounted the four bearing pieces, countersunk the holes for the roller bearings, and mounted the nut for the thread. Currently missing three 8mm flathead bolts, more rail (one piece has its hole too far towards the side, grumpf), an 8mm drill bit that's not dull as all get-go, and 4 more roller-skate bearings. Improvements in this stage: Rounded the sides of the rail bearing acrylic pieces, hopefully lessening the wear. Snipped the corners of same instead of dremelling them down, much easier. Rollerskate bearing bolt holes are now fully countersunk (not that it's really necessary) due to diligent testing and hand-improvement.
This is going to be the ugliest RepStrap evar:)