ReliaBot 100mm T8 T8x4 Tr8x4 Lead Screw and Brass Nut (Acme Thread, 2mm Pitch, 2 Start, 4mm Lead) for 3D Printer and CNC Machine Z Axis: Amazon.com: Industrial & Scientific
200pcs) DIN 6926 M8 Self-Locking Hexagon Flange Nuts with Serration A4 Stainless Steel, Ships Free in USA by Aspen Fasteners, ASSP692648: Amazon.com: Industrial & Scientific