The gantry is based on the L-shaped design - by Dean (JazzCNC on mycncuk.com). This uses 2 pieces of heavy 45mm by 90mm aluminium extrusion bolted together in an L-shape. This makes for a strong gantry and also has the advantage that the t-slots line up with the ballscrew mounts so they can be bolted directly on. The Hiwin linear rails can also be bolted on directly. The sides of the gantry are 15mm aluminium tooling plate - the aluminium plates for this machine were cut-out (slowly!) by the old cnc router. The gantry sits on 2 plates which bolt onto another 2 plates connected to the x-axis bearings - this means that the sqaureness of the x and y axis can be adjusted by loosening the bolts.