Hi everyone:
What fun, well for my 2 cents worth on this subject and from my experience working with hewn timber where all timbers vary at times dramatically what I would do is this--
For the exterior posts I would work with lines 2" from the outside surface--do all your layouts from this line forget the inside surfaces for now.
overall width measurements would be calculated from this line plus 4" (2" on each post beyond this line)
As stated above you will have to cut varying depths of seatings into the inside surface of the posts at the points of intersection of cross girts, and I might add all brace seatings.
Some posts like corner posts will be much trickier because of girts and braces coming together on 2 of the vertical surfaces from 2 different directions. For these posts you will have to work 2" from two of the best and squarest sides.
You will find that not many bandmills will provide you with timber much better than you already have so you might just as well work with what you have.
Large companies would take time to resaw, or plane the timber perfectly true (or very close) in the end it would save them much time and money.
The centre posts though will be easier just work from a centre line as has already been pointed out above.
Make no mistake when you have finished this small shed you will look at a large timberframed
building with awe realizing that the tradesmen that put that all together was working with timber of varying dimensions, hewn rough surfaces, and in many cases twisted just enough to make life very interesting.
Good luck on your learning experience, I am sure it will turn out well if youlisten to those that that will try and give you advice.
NH
