First of all, I have all copies of Fine Woodworking, including the issue
with the coring lathe. Secondly, I own (and use) both the McNaughton System
and a home made system for coring bowls. The problem (one of) with the
commercially available systems is that you have to reduce the half log to a
hemisphere, then reverse it on the lathe and core out the largest bowl.
Then take the core, reverse it again, turn a tenon, take it off, reverse it
back onto the lathe, cut the next core. Do this for each bowl. Takes a lot
of time, and the cutters are kinda flimsy when they extend out over the
support by 14-15" (measured along the curve).

The machine in FWW was over 100 years old, used !/4 arc cutters (same as I
am looking for) and still works fine. But they have one guy whose full time
job is to sharpen the cutters and maintain the machine. I don't anticipate
making that many bowls, but I sure hate how long it takes me to make 3 or 4
bowls blanks currently.

Thanks for all the replies.

Regards, James