This design replaces the original plastic arms and acryllic plates. All aluminum, except the BuildPlateCorners, PlateClamps and TrimKnobs are printed parts, ABS. The original linear bearings are re-used in this design, as are the heated buildplate parts, springs, bolts and nuts. The springs and long bolts are moved to the corners of the buildplate, giving more accurate levelling compared to the original design and... No more warping of the arms when the buildplate heats.CornerLeft and ..Right are 2mm aluminum plate. To work accurately first bend the plates, then drill the holes. The Arms are out of 15x15x1.5 mm square tube aluminum extrusion, the inserts 12x12 mm bar. Drill the holes after inserting. The linear bearings are mounted with circlip springs in pieces of aluminum bar 30x15 mm. Near the bearings the bar is milled to 9 mm thickness. These bearings, as saved from the original plastic arms, are provided with grooves for clips. Boltholes in the bars are drilled 4.2 mm and threaded with M5 threads. I used 4 M5x30 bolts, 2 M5x20 and 4 M5x16. The touchbar for the Z-limit is 20x2 flat piece extrusion, fixed with 2 M3x8 bolts in slots of the corner pieces. The trimknob insert, brass, is also threaded with M3, like the touchbar.