I want to make some parallel half round flutes about 6mm wide in a piece of oak. I could do the straight part with a router and a round nose bit. But part of the fluting follows an S curve so I can't use the router table or fence on the router (or can I?) I suppose I need something like a bearing or bush guided side cutting slotting cutter with round tips. Does anyone know where I can get a bit like this? The only one I can find is a very expensive matched fluting/beading pair from Axminster. Is there an alternative? How would you do this job?