Linear Shaft and Low Support Rail - Carbon Steel - LSG12-012.000-SL (for bolting together) Diameter: 3/4" Length: 12"3 4" diameter precision case hardened and ground steel shaft, with a matching 12" length low profile LSR steel support rail. This assembly comes as a two piece set with a separate shaft and support rail. You can bolt the shaft to the rail to save installation time. The shaft's lifespan can be doubled by rotating it for a fresh surface when wear appears. Both sides are counterbored, allowing for a 180 rotation and rebolting for use on the new side.