In the very centre of the cabin I installed an adjustable jack post to allow me to lower the loft (and middle of the roof peak, by extension) as the outer walls of the cabin settled.
While I can tell that the outer walls have settled a bit more than an inch, my monitoring with my level kept insisting that the main support beam and the floor joists attached to it were still true.
This really shouldn't have been possible I think, and so the recent appearance of the stress fractures in my insulation gave me the impetous to make my first adjustment to the jack post.
It was a devil of a time just getting started. My 1" wrench was too sloppy, and my 7/8" wrench was too tight.
Grandpa brought over two of his antique adjustable wrenches, but neither one of them were able to fit. They could open the right amount, but the grips were wider than the flattened portion of my jack post, so I was unable to gain any purchase on the post.
I added a 15/16" wrench to the shopping list and left it at that.
The next day, while in the yurts fumbling for an unrelated tool, what should I uncover? You guessed it! My 15/16" wrench!
I brought it in, and it was a VERY tight fit. I actually pounded it on with my deadfall mallet, and then used the mallet to turn the post once around (about an eighth of an inch drop). The next day I repeated the process and then decided that I had had enough for awhile. I did hear a number of creaks and bangs from the cabin over the next day or two, but I don't know if I should ascribe that to the adjustments I made, or the frigid temperatures we continued to experience.
The next time I was at the hardware store, I opted to purchase a 25mm wrench, assuming that the jack post was metric and that would be the best compromise. It bemused me to later find the packaging for the post which marked the suggested wrench as a regular 1" - the first one I tried! I'm not sure why it was so loose in my case, but I'm happy with the 25mm wrench.
In keeping with my new wrench philosophy, I hung the new wrench right on the jack post.
My new philosophy, created in the wake of searching for the proper wrench size and location EVERY generator oil change (12mm in case you are curious) is that it is more economical to simply purchase a wrench for each location where it is needed on a recurring basis, and leaving it there, rather than trying to record and/or search out the wrenches from a toolbox as needed.
I'll still keep a full selection in my tools, but for things that I use the same size for over and over again, I'll have a primary copy right on-site.
As for the jack post, I will perhaps take another look at adjusting it in the spring. The settling of the cabin seems to have slowed based on the progress of the outer walls, and I have begun work on the panelling that requires some long-term stability from them.
Post Script: CW! from church - tell my Dad I say hello!