Sunday, July 25, 2010

Offering


I spent the morning out among the logs and just got to the point where I was able to offer up another tenon to its home mortise. Basically the bottom corner of the big log C shape from the viewpoint here standing up on the road above the yard area.
If you zoom in, you can get an idea of scale, there is a mortise hole in the beam lying under the back of the C, that hole is 150x45mm.
The whole procedure is a bit biblical, and I am working very close to the limits of what I can manhandle single handed without winches or anything. Need to keep the brains focused on the job at hand to avoid dropping something off of the rack.
So far it is proving doable within the space and I think I will be able to manage all the joint cutting in this way. Extending the rack to accommodate all the timber has meant that I get a good workout skipping up over it every time I need to go from one end of a piece to the other, like spending the day on the parallel bars.
The main point with big frames constructed with irregular timber is to provide oneself with reference lines on the timber, these lines represent the lines where planes through the timber push out through its surface. Usually planes through the centers or level planes. Each of the pillars has four longitudinal ink lines on it that correspond to planes crossing through the center. As long as the timber is stable on its rack you can use a spirit level and draw a cross of vertical and horizontal lines on each end that passes through the center, then snap an ink or chalk line between the tips of the crosses on the ends right along the timber. These lines allow me to make the marks to cut the vertical tenons and will later give me the centers for other mortises and tenons. The beams have lines along their "sides" that indicate a level plane through them, not usually on center and a vertical plane through the center. The level plane lines will allow me to use a big set square or three four five measurement to check the beams and pillars for squareness while they are lying on the rack and also cut the pillar bases to length when I have put in the four big rocks that they will stand on.