I'm not sure that the following could be construed as "General" woodworking, but it does involve some heavy duty "power tools" and it certainly involves both "wood" and "work"!
As many of my fellow SMC members are aware, I have a sawmill and kiln drying operation on my farm. Recently, my farm received an order for some extraordinarily long (and large) timbers that will be the basis for timberframe structure to be used as a restaurant and bar outside of Washington, DC. The structure is being built from red oak, and the focal point of the timberframe will be a pair of rough sawn oak beams measuring 12" x 16" x 42'.
A hundred years ago there were probably thirty or forty large sawmills operating in the west and northwestern United States that routinely milled beams such as this (as well as much larger). However, due to limited demand today as well as limited availability of large (and long) logs, few commercial mills still exist that can manufacture something like this. Fortunately, the sawmill that I own is designed for large logs and is very versatile. Coupled with enough track, a crane and other heavy equipment we're able to produce the beams here on the farm, and I thought that some of my fellow SMC members may find the process of interest.
Probably the most difficult portion of the project was sourcing a pair of logs that were at least 24" on the small end, 43' long and clear. Fortunately, some logs were sourced nearby, and although we are waiting for engineering to be completed on some of the smaller beams, we recently started the milling process on the largest ones. There is a lot of log handling involved, as each log has to be turned multiple times in order to properly mill it, and the bunks have to be readjusted with each turning.
After sourcing the logs and having them delivered to a local concentration yard, the work started by reviewing a gorgeous pair of red oak logs and subsequently having them loaded on my trailer. They are each 43' long, with small end diameters of 24" and 26" respectively, and they weigh approximately 6 tons apiece.
After unloading them at the farm, we used a crane to load them into the sawmill bunks and then laid out the beam profile on the ends of the logs.
Milling then commenced on the first face:
First face is complete (and inspected by Shea, our "log dog").
After the first face was milled, we used a crane to remove the log back out of the bunks, then used a backhoe to align it for the second face, readjusted the bunks and then set it back in and started milling face 2:
These next photos are probably my favorite ones of the entire group, as they provide a good perspective of the sizes and proportions of the beams being milled.
After completing the milling on each face, that face was soaked with a 15% TimBor solution to help alleviate any pests in the finished product (since they sure won't be going into one of my kilns!):
The next step is to mill the first two faces on the second log in a similar manner. After that we will adjust the bunks to be perfectly flat relative to the sawmill and mill the second two faces on each log.
Working with long, large logs is very different than typical 8' - 12' logs, not only because of the mass involved but also because every step must be well thought through in advance and executed without any mistakes (so nobody gets hurt and also I sure don't want to have to "eat" one of these expensive logs due to a mistake!). Working through any tension present in the logs is also a challenge; additional steps are required to mill oversize, with multiple log turns and milling some of the faces more than once to get down to a final dimension that provides for equalization of any tension present in the logs that is revealed during the milling process.
The log weights are significant (over 12,000 lbs each), and extra caution has to be used when handling and moving them around with the crane. I have a 6' Logrite cant hook, and these guys just laughed at it! All handling requires heavy equipment for every step, and precision handling to set them up just so. Because the beams are oak and will be left rough sawn, we also have to prevent contact with steel forks, chokers, etc to the freshly sawn surfaces.
I'll post some additional photo's next week as time allows.
Scott
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