I've turned my bandsaw into a mini sawmill with the help of one dirt-simple jig and a pair of extension tables. The jig is nothing more than a piece of plywood screwed to the log. It steadies the log when I cut the first slab and provides additional support when I rotate the log to saw boards (see photos).
My bandsaw is equipped with a fence to guide the jig and a riser block to accommodate the additional height of a log. I use a very coarse 3/4-in. 2-tpi blade for sawing thick, green wood (see Source, below). My jig is a piece of 3/4-in. plywood 12 in. wide and 6 ft. long. (The largest log the saw and my back can handle is 11 in. dia. and 4 ft. long.)
Attaching the plywood to the log is easy. I just lay the plywood on top of the log and drive 2-in.-long deck screws at three or four points where the board touches the log. (The screws should penetrate at least 1/2-in. below the bark.) I lift the log onto the extension table and pound some carpenter's shims under both sides of the log to keep it from rocking. The first cut goes through both log and plywood. This creates a flat surface to support the log on its side for the following cuts.
I flip the plywood jig on its side and ride it against the fence to saw boards. The jig automatically holds the log at a right angle to the first cut I made.
Suffolk Machinery, (800) 234-7297
2-tpi PC Series 3/4-in. x 105-in. blade, $24.