BOB tools as I call them (bottom of bowl) because I thought some one had a 'signature' bottom feeder as a name, are a specialized tool for getting through the transition and across the bottom of the bowl. There are many variations. They range from bevel angles of 60 to 80 degrees, and most have a very slight sweep to the nose profile, kind of ) shaped. I always do mine on a platform, but then I do every thing on a platform... Do grind away at least half of the heel on the bevel to allow it to move through the concave shape with ease and not leave bruises on the wood. I do keep mine rolled all the way over on the side, flutes at 75 to 90 degrees, and handle slightly dropped. Very light touch: "The bevel should rub the wood, but the wood should not know it." I have a number of different ones, but one of my favorites is Doug's fluteless gouge, and a couple of shallow fluted detail/spindle gouges with the ) nose profile. Also one old Craft Supplies 1/2 inch gouge with pretty much a half round flute shape...
robo hippy