T-Slot Aluminum Extrusion Manufacturers

My question is - why use expensive extruded aluminum T-slot? I mean, for a CNC router it makes sense because you need sub-millimeter

The x 180 mm tabletop aluminum extrusion is perfect for workstation table tops, CNC worksurfaces, machine-tending workstations, and more

aluminum v slot T Slot Aluminium extruded profiles are used to create a framing system that uses the slots along the face of the extrusion to hold a variety of nuts and

aluminum extrusions tslot Aluminium Extrusion satin anodised, strut profile PG30 with a dimension of 30x30mm and 4 T-Slots perfect for light to medium applications