Many logs, especially oak, have a tension present in the log that is released during the milling process. This tension causes the log and/or boards to move (I have actually seen boards lift themselves off of the log while being milled due to tension). Because the scarcity of large logs suitable for this project (as well as the expense), I opted for a conservative approach and milled two of the log faces twice, instead of just once. The initial milling resulted in a beam that was around 1” thicker and wider than needed. We then subsequently turned the beam back to the initial faces for the final cuts. Because 90% of the outer wood had already been removed, the bulk of the tension had been released in the logs/ beams and we could now safely mill to the final dimensions. The tension was clearly evident, as the slim boards now being removed from the beam faces tended to vary slightly in thickness. We also accounted for the location of the pith in the log when milling, so as to achieve the best balance between milling needs and center pith (to minimize future beam movement due to unequal stresses on the different beam faces).
This photo shows the progression of milling the final inch out of the last face:
The beams are now complete! Here is a photo of the finished narrow and wide faces on the beams:
When complete, the differences in width and thickness from end to end was around 1/8” – 3/16”; which is a reasonable tolerance for something this size.
The last step was to crane the finished beams out of the sawmill and onto one of my trailers for subsequent transportation up to a drying barn.
They will stay in the barn out of the direct sunlight until we are ready to deliver them to the jobsite in Washington, DC.
I hope that everybody has enjoyed this post; it was certainly a fun and interesting project!
Scott
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Originally Posted by mreza Salav
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