Abstract: A rail assembly includes assembly includes a fixed carriage and a clamping system. The fixed carriage defines a receiving area and a rail at least partially supported within the receiving area. The rail is slidable along an axis relative to the receiving area. The clamping system applies a clamping force on the rail within the receiving area. A movable assembly may be supported on the rail such that the movable assembly is movable along the axis relative to the fixed carriage.

Abstract: Described is an adjustable friction slider assembly having a rail member and a carriage assembly moveably coupled to the rail member, the carriage assembly having a bracket member and a plurality of roller elements moveably coupled to the rail member and coupled to the bracket member using a plurality of attachment members, the plurality of roller elements comprising at least one adjustable roller element coupled to the bracket member using a moveable attachment member, wherein moving the moveable attachment member adjusts a friction between the plurality of roller elements and the rail member.