My initial turnings with the articulated arm were around 6" long. Hollowing was simple and smooth. When I do 8" I get a lot of vibration. I have some big logs at back that I don't think I'll be able to hollow with the arm.

Have you hollowed 12" or more with the d-handle? If so, what were your experiences and what boring bars and cutters did you use?

Thanks,
Burt