Hi Keith,
I did in fact use the sorby tool and the medium size cutter, can't rember the size right now. I've used it on some pear and it did fairly well but didn't have as much luck on mesquite or cherry. I've not had it long.
I had the tool rest above center and tailed the tool down below the work. Slowly bring the tool up to cut on center and you have to try and keep it on center or you will get waves in the spiral. Hold it steady with light preassure against the work until you get the start groove then you can stare to feed into the cut lateraly. go slow and don't try to cut the full depth of the spiral on the first pass just cut an index groove,if that makes sence,the cutter is self indexing back into the groove .Had the best luck at 500rpm but I assure you I no expert with this tool and I think the hardness of the wood lends alot to the sucess of it.Jatoba is one of the hardest woods I've encountered yet and it worked very well on it.I tried it on a cherry box and had to cut off the mess.
I like the spiral box.
And now, with the help of Chris, and the Sorby demo CDs, I can see how you did it. Very nice work. At first it seemed like a job for a metal lathe with a lead screw. There goes my 'tool' budget.
