You apparently do not hollow as I do. Had occasion a few years back to check my interior timing on 10 to 13 " pieces to compare with coring challenge. Seven/Nine minutes switch on to set down, IIRC. Not as fast as George's coring, but I have a perpetual supply of northern hardwood to work with, and the stove sometimes wants a relight, or the chicken lady some bedding, so that's how the interior leaves. I don't use a spur drive, because it's too easy to cam out with wet sapwood. Schoolkids just aren't too careful, sometimes. The thing's made for long grain, as you know. If new guys are planning on using, give a 1/4" deep counterbore to seat in, just in case.