Missed this thread the first time around, but a steel wire wheel on a drill can offer a random texture pattern. It won't leave a sharp transition to the untextured parts- you may need a bit of sanding or even skew/gouge work at the transition zone if you want a sharp transition. Using it on a slightly wider wood diameter acting as a transition may help. Varying drill speed, lathe speed, applied wheel pressure, and rotating the angle of the wire wheel to the wood surface are all worth experimenting with. Wood density/hardness plays a roll as well. Experiment on scrap first.