|Reclaiming hardwood lumber from the urban forest in the Eugene/Springfield area has been nearly as much a passion and adventure for me as woodworking itself. I find it amazing the amount of high quality hardwood that is removed each year and turned into firewood, or worse, chipped or deposited in the city brush piles. Certainly there is a great quantity of the trees removed that are rotten or compromised by wind or pest damage that truly are best returned to the earth. Limb wood is some of the best firewood around based on the high number of growth rings per inch and ease of handling compared to large rounds. But there are many trunks that are of a high enough quality to warrant use as saw logs. I collect and use big leaf maple, walnut, elm, locust, myrtle, ash, oak, and cherry as well as others. I find the beauty and quality of carefully selected urban forest lumber to far surpass that available though any of the hardwood lumber retailers. I do not cut down live healthy trees. I only use trees that have fallen or are removed by arborists because of disease, rot, danger, etc.
Just as important as selecting good stock is how the logs and lumber are handled as the wood becomes stock for furniture. To sum it up: slower is always better. Starting with the raw logs, I find sealing the cut ends on saw logs with wax based paint within an hour or two after felling/bucking makes a significant difference in how much end check (cracks) develop in the finished lumber. I always try to mill my lumber in the fall or winter to allow the initial moisture release to be slower during the cooler part of the year. Milling in the summer is a recipe for potato chips – cracked, warped lumber based on moisture escaping from the board surfaces faster than the internal moisture can migrate to the outside. Even better is allowing logs to rest a year before cutting them up. I find a lot of the stresses the tree is subjected to while growing are reduced if the green log is allowed to sit.
I use two methods for milling the logs into lumber. The one I've used the longest is the Alaskan chainsaw mill. This is basically a chainsaw bolted into a frame that can be run on a straight surface to create lumber.
When starting out, the straight surface is provided by an extension ladder screwed to the top of the log with plumbers tape. After that, the mill rides on the previous cut.
As evidenced by the name, Alaskan mills were designed to be put into a bush plane and flown out into remote areas to create lumber for trail work, cabins, brides, etc. Its slow, dirty, physically exhausting work, but slabs are created from which boards and veneers can be later sliced.
The power head for the Alaskan mill is a Stihl 090. Sometimes referred to as the "granddaddy of the woods" the 090 was Stihl's largest production chainsaw. With 128cc and developing about 13 horsepower, the 090 is capable of using bars as long as 8 feet. While they are no longer produced in the U.S., the 090's still command very high prices on the market as power heads for Alaskan mills. These saws were used to cut the massive old growth trees that were once so prevalent in the western U.S. While it is sad to think of the stands of old growth being harvested, I do have a lot of respect for the men that carried and wielded these monsters every day in the woods.
The advantage of the Alaskan mill lies in its portability. I can take this setup into a back yard, for instance, and remove the slabs one at a time. Working from wide slabs is different than working from milled lumber. For one, pieces can be laid out on the slab much like cookie dough, taking better advantage of grain and color. Wide slabs also require more initial break down to get it into useable form. This requires careful layout and time with a skilsaw, the band saw, and the jointer.
Another type of mill I use is a circular mill called a Mobile Dimension. I happen to fortunate enough to have two friends that each own one of these expensive pieces of equipment. It uses two blades at once, one in the vertical position and one in the horizontal position to cut boards directly from the log. The advantage of using the Mobile Dimension mill is in the ability to select for grain direction. The sawyer can adjust the position of the blades on the fly and cut boards from the log in different sizes and shapes to best take advantage of grain. I find this particularly useful for creating vertical grain (VG) boards for panel frames, etc. and rift sawn (diagonal) boards for use as leg stock.
All boards and slabs are then stickered and air dried in my drying shed for at least a year, more for thicker lumber. It will remain here until it becomes 'Oregon air dry', about 13-16 % moisture content. From here the lumber goes into my solar kiln to dry it down to the finished 6-8% moisture content needed for making furniture. The solar kiln uses the sun's rays to heat sheet metal collectors inside the kiln. Fans hung in a plenum drive air across the collectors and the resulting warm air through the stack. The solar kiln is very gentle, heating and cooling the lumber each day. This again is where the slower process pays off. As the moisture slowly migrates from the core of each piece to the outside surfaces to evaporate off, the fibers in the wood are allowed to relax at a slower rate resulting in straighter lumber with far fewer drying defects. Another advantage is that resins and tannins in the wood are allowed to remain instead of being driven off in the high heat, rapid drying process that commercial kilns use. The result is color you cannot find in commercial hardwood.
The wood is then held indefinitely in a special dry room at about 45% relative humidity (same as the average home in the western U.S.) until it is used in a project. It takes a lot of time and energy to produce wood this way, but I feel the results are well worth the effort. I love shopping in my own 'wood store' for a project!
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