Sommerfeld Bull Nose Router Bit Woodworking Tool 1/4CR,1-1/8CD,1CL,2-1/4OL,1/4SH These bits can produce finished edges of stair treads, table edges, windowsills, or shelves. By selecting a smaller diameter bit, you can create a half-round bead. By using a larger diameter bit, you can make an elliptical curve on the edge. With two passes, it can also make dowels.