Turners need to use the bandsaw to make the initial cut you showed. The weakness in this set up is the need to follow a line by eye, which is not likely to produce a truly flat cut.

The jig I made solves this problem.

The base of the jig is a piece of 1/4″ plywood about the size of the bandsaw table. I added a piece of hardwood on the bottom to fit into the slot on the bandsaw table so it would run dead straight. This was done so the plywood just reached the throat of the bandsaw.

I then ran the plywood through the bandsaw about half way.

I then made some upright pieces perpendicular to the bandsaw cut, 2-3 at most, to each side of the plywood. I then cut a few (equal to the number of uprights) pieces with an angle (say 45 degrees) at one end.

To use this, I pull the plywood jig almost out past the blade, place the log up against the blade and passing through the pith, and add the front two loose pieces so the angle cradles the front of the log in place. Then I go to the back of the log draw a line perpendicular to the table up through the pith on that end, and place the back two angle pieces to cradle the back end of the log. The angled loose pieces are held in place to the upright with small clamps.

Now as I run this through the bandsaw, it will be just where I want it down the pith, and dead flat (provided the blade doesn’t have much drift).

When I store this jig, I place a small piece of wood with a groove equal to the thickness of the plywood, over the opening cut in the plywood, so it says flat.

(Very hard to describe this only in words — sorry)

Gordon