Thanks for responding with your solution, I suspect for the first step in the hewing process of these large logs.
Splitting large sections off the outside circumference of the logs, in my books sounds like a reasonable way to move forward quickly.
I know in one barn that I examined that had a swing beam, (which for those that are not familiar with the term is a very large beam that spans one side of a barn floor, and is usually 9 or 10 inches square on the ends but at the centre is maybe 9" or 10" by 24" in height), now this barn had very large floor planks that were split out on one side, and the upper sides were flattened and smoothed off with an adze. These could very well have came off the large timber that was procured for the swing beam. These planks were very thick and uneven in thickness along their lengths, and were over 3o" in width. I could also be wrong though in my assumption, and these planks could have been split specially for the flooring sequence of the construction of this very early barn. One thing that I am basing this assumption on is that the length of the planks were 10 feet shorter than the swing beam.
Now I ask the question Mark, say that this large log was procured for you and you only had one log no spares, would you feel confident enough to continue on with your action plan? and if so what type of tools would be needed and used, given that you only had the historic variety of that period.
Mark thanks again for your input and your solution as it unfolds.
I ask other knowledgeable people on this thread to jump in with their solution given that they were chosen to head up the construction of one of these buildings, and were also given the raw material, manpower and capital to prepare this structure in a historic correct fashion, (no cheating) complete with these large timbers for their respective places in the timberframes.