Nice tip. I had similar problems trying to turn very long dowels for
some furniture and found that a great way to turn extremely long, thin
dowels is with a hand plane. Start with an octagon rather than a square
because it will whip too much to use a tool and you can't hold a
spinning square in your hand. Wear gloves and keep your fingers away
from the surface until it's close to round. You can use one hand as a
steady rest on the back side and the other hand to hold the plane at an
agle that would be like a real acute shearing cut with the skew...maybe
45-60 degrees or more off the axis of the dowel. As it gets rounder,
you can bring up the tool rest and use it to stabilize the plane to
make a really straight cut, and you can increase the angle of the plane
edge to make a thinner slower cut for a real fine surface.