"Prometheus" wrote: (clip) Does anyone know a technique for turning these
freehand with a turning chisel, and if so, is there a description of the
process somewhere on the internet? (clip)
^^^^^^^^^^^^^^
There are videos that teach this. A good one is by the talented British
spindle turner, William White (I'm pretty sure that's his name.) Basically,
it is not really a turning proces--it is done with the lathe stopped. You
lay out a series of equally spaced circles in pencil, and a group of equally
spaced axial lines. At this stage you have constructed "graph paper" around
your wood. Then draw diagonals in the squares, and you wind up with a
spiral running like a barber pole along the wood. Then you HAND CARVE the
unwanted wood away, to leave a spiral.

By changing the spacing and the way you draw the diagonals, or the number of
diagonals, you can create a multitude of patterns.