Sommerfeld Bull Nose Router Bit Woodworking Tool 5/8CR,2CD,1-3/4CL,3-3/8OL,1/2SH 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.