I guess sawing is a form of hewing. Stud mills take small trees and put them through a 4 sided chipper head, than that cant goes through a gangsaw and out comes 3 or so 2x4's. As for the 12x oak, does it have some large checks, if so you will have to saw around those. Just saw it through and through to yield 12"x5/4 boards, look at your grade and resaw those on a table saw as needed. Here is another gamble, place it on the sawmill with one corner down on the track, in a diamond shape, saw a 4"ish triangle off the top, maybe 5", save it to resaw later. Flip the cant 180 degrees, saw that through and through to yield wider 1/4 sawn stock. Tim