FIRST OFF< I LOVE THE XTREME ROLLERS.. I can blow on the track and it moves.. the 3D printer stuff I bought before is crap, going into a box and get tossed into the corner. HOME CNC drilled Ox plates, just the holes, not the outside contours.. you could do the same thing CHEAP by printing on paper 1:1 and then punching the centers, and using a drill press.. I used to do that for IC chips all the time, then drill right through the paper. Planning on Running 8 rollers on the Z axis, 20x60 rail. Checking measurements on holes, how I got those hole locations is kinda nuts, converted Dxf to autocad file, drew circles on the HOLES with the circle 3p function, then took it into Lazy cam (comes with mach3) picked the big drilled holes, then made a second file and picked the small ones after a M06 call to stop program to change tools. I am moving the 400oz motor to the siderail, planning on using the 12mm rail, it is the one good part I bought for my 3d printer build. When I decide to expand my travel I will buy the big siderails. Whole router-printer unit will Crawl down a 20 foot Ibeam on a trolley and pneumaticaly lock in each position. I am working on carving 20 foot parts here for some unique things I am building. A plasma torch will go on-off the unit as needed, as will a scanning probe, and the plastic printer nozzle-head. Basically I want a LONG axis travel high tolerance gantry machine that is a fit-all.. I will be welding the Ibeam up over the next week here, wish me luck on not getting crippled working alone.. Planning on using the Sainsmart controller w/lcd thou so far I am still puzzled by the chinglish translation, could use some help getting the lcd to work. It seems to work well with the Rasberry pii and the grbl controller software. as it does with a homemade program. Right now it runs with Mach3.. THIS frees the computer up to do modeling and run the other shop toys. Checked the cross travel holes too.. they line up too.. I was tickled considering how I created the G81 drill file.. I thought it was a risk to even drill a piece of aluminum flatbar with a possibility of failure. My wrecked shop, old converted bridgeport from paper tape programming to Mach3, computer (about 2001) THE drives, Geckos, 400 oz motors by Geckodrive.com and a sainsmart TB6560 3 axis drive, actually works pretty well, just limited current on them.. MY 3d printer ran so fast back and forth the big box I had it in was rocking a foot in both directions.. the sliders were crap thou, and I started looking for a upgrade before I put it into use. My wife gasped when she walked in while I was moving it back and forth under G0 Commands. I am very happy I found you guys.. If I can help anyone else, holler..