The manufacturer provides equations for calculating how strong the extrusions are on pages 11 and 12 of the Manufacturer's Catalogue. Obviously the smaller extrusions will not be as strong and rigid as the larger extrusions. strength scale your project ends up falling. The series you end up using depends where on the weight vs. For each series we carry a single (20x20mm, 30x30mm, 40x40mm) and double (20x40mm, 30圆0mm, 40x80mm) wide extrusion. Phidgets carries three different series of T-Slot extrusions. T-Slot is a framing system composed of extruded aluminum profiles which use the namesake slot as a mounting point for various hardware components.