Which router bit do i need

[ipjodan]

Hello i will try to explain this the best i can.

I want to round over my window board the same as the ones already in place. The boards are 25mm thick and have a nice semi circle on the front. Do i need a 1/2 inch round over bit with a ball bearing roller?

Thanks

 

[big-all]

not quite

you need about a 2mm flat edge for the bearing to run on so you either run your 12mm radius cutter 2mm shallow or use a smaller radius
you will finnish up with a 4mm flat but this cant be helped as you have a gap between bearing and cutter with a round edge on the bearing

you can use a fence and table if you have one and finnish up with only 1mm bearing surface and no bearing marks on the wood