Trend 46/93X1/4TC Bearing guided ovolo cutter 7.9mm radius Self-guiding cutters for rounding over edges do not require a side fence.
They are supplied with two bearings.
Use the larger bearing for a round-over.
If the cutter is lowered, a top quirk can be produced.
A full round/bullnose for stair treads can also be produced by taking a second pass from the opposite side of the workpiece.