The following project will allow you to install 2 fully supported THX Linear Rails in place of the Z Axis 8MM linear rod found on the Lulzbot AO-10x series printers. It also upgrades the Z endstop for additional precision. PREREQUISITES: After completing the 60MM height increase and AO-TAZ modifications, print 4 Upper Spar mount pieces ( Right and left 2 per plate in STL), 2 Lower Z motor mounts, the Reinforced and extended X motor End Clamp, and the two new backplates (you cannot reuse the existing AO-Taz backplates). At this point, choose which Z endstop to print. If you choose the Micrometer based one, Order one of these micrometers and cut the upper C arm off (http://www.ebay.com/itm/360702635282?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649) Other micrometers should work If that one is no longer available. You will also need to fabricate out of aluminum, or print the 4 angle plates. You will also need 2 THK RSR12VMA 14.5 inch long linear rails with two carriages each, two 384mm long 20mm extrusions, 4 80/20 TSlot Aluminum 20-2020 x 160mm Long 45 Degree Support 20 Series 20-2565 N angle extrusions (http://www.ebay.com/itm/331078816324?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649) , and potentially some Aluminum plates. You will also need 52 M3 and M5 T-slot nuts, washers and cap screws, some to secure the rail to the extrusion back spar, some for the plastic parts, etc. If you are attempting this project you can probably figure that bit out. The upper spar mount plates are designed to bolt to the side of the existing upper gantry pieces that hold the linear bearing rod, and are secured using the existing bolts. The lower motor mounts replace the existing units. Please note you will most likely have to unplug your Z axis motors to proceed with that mounting step. The X motor mount clamp end replaces the existing unit. You will need to extend your belt to compensate for the additional length. The rail carriages secure to the new backplates using flush mount screws, countersunk, and then are bolted in place on the X ends using the existing Z nut spring hardware and the hardware that was holding the 8MM lm8UU bearings. The Z endstop target will either use the existing endstop hardware, or receive the cut down micrometer end. The micrometer end will need to be drilled to accept 2 holes in the remaining shaft to ensure that it cannot move. The holes for those are not currently part of the printed part, you will need to drill them once you know where they will be on the micrometer remnant itself. The lower Angle extrusions will be too long to fit. You will need to cut about 15mm off at a 45 degree angle parallel to the existing end, leaving you with a piece that is 130mm long on the longest side. Bolt everything together, ensure smooth travel on all pieces, and then print away! Troubleshooting: The wildcard in this setup is the backplate thickness. Assuming you got a really good starting layer, they should be just thick enough to engage the linear rail and the X end clamps. If you find you are binding up on z travel, this may be either too thick or too thin. Also watch that your bearings are parallel and spaced properly. You may also need to move the X end clamps in or out on their bearing rods as neeeded