Crosscut saw
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A crosscut saw is a saw that is specially designed for making crosscuts. A crosscut is a cut made horizontally through the trunk of a standing tree, but the term also applies to cutting free lumber. "Crosscut saw" is a blanket term that includes smaller traditional carpentry saws and larger saws used for forestry and logging work.
Crosscut saws have teeth that are designed to cut wood at a right angle to the direction of the wood grain. The cutting edge of each tooth is angled back and has a beveled edge. This design allows each tooth to act like a knife edge and slice through the wood (in contrast to a rip saw, which tears along the grain, acting like a miniature chisel). Some crosscut saws use alternating patterns of the cutting teeth along with others, called "rakers", designed to scrape out the cut strips of wood. Cross saws have much smaller teeth than rip saws.
Some saws, such as Japanese saws and those used by the ancient Egyptians, are designed to cut only on the pull stroke. Western saws, on the other hand, are designed and sharpened to cut on the push stroke.
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[edit] Common features
Many crosscut saws have a wooden handle with the return edge at right angles to the un-toothed edge of the saw blade, allowing the saw to serve as a square for marking material to be cut at a right angle.
Larger saws used for forestry and logging work include both one-man and two-man saws, and both bucking and felling saws. A bucking saw generally has a straighter back and less of a pronounced curve on its cutting surface. Since bucking saws are more often used on trees that are already downed, the greater stiffness and weight aids swift cutting, and allows two-man saws to also be used by one person, pushing as well as pulling.
A felling saw is generally less stiff than a bucking saw and the backside, as well as the cutting side, is usually curved inward. Felling saws are more often used to cut down standing trees, so the thinner, lighter design is easier to use without gravity holding the blade against the cut. The concave back of the saw makes it easier to place wedges, preventing the kerf from closing on the saw.[1]
Crosscut saws also include smaller hand saws used in carpentry.
[edit] How crosscut saws cut
As described above, saws may have cutters, rakers, and gullets.
As the saw is pulled toward the operator, the cutters along the saw's surface score the wood to the left and right of the width of the blade, cutting a channel downward into the wood. Many sawtooth patterns have 4 cutters; each cutter that cuts to the left of the blade is paired with another that cuts to the right of the blade.
After the cutters there is generally a raker followed by a gullet. A raker is what does the actual removal of the wood that is being cut. The raker follows the cutters, scraping the bottom of the kerf. As the raker scrapes the bottom of the kerf, the wood is peeled back and stored in the gullet which follows the raker.
As the saw is drawn out of the kerf, the wood that has accumulated in the gullets is allowed to fall out onto the ground. A way to determine whether a saw is working well is to examine the noodle shaped strings of wood that are scraped out of the kerf; the presence of fairly long strings indicate that the side cutters are doing their job and that the raker is slicing out the wood cleanly.
[edit] Crosscut saws vs. chainsaws
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Crosscut saws and chainsaws each have safety issues. Crosscut saws require much less training, and are safer for unskilled operators, however, in the hands of a skilled operator, they are both reasonably safe tools for an inherently dangerous job. When backpacking equipment into the forest, crosscut saws require less weight to be carried in on people's backs. Chainsaws require fuel to run, a few tools and basic mechanical ability to maintain. The primary maintenance carried out on crosscut saws is sharpening, which cannot be done in the field, and must be done by a highly skilled filer. They are usually sent away to be sharpened once a season.
Crosscut saws have three main disadvantages for felling and bucking timber. First, they are much slower than chainsaws, which reduces the amount of work done, and can be very dangerous when felling a tree with a heavy head lean, or bucking a log with an extreme bind. Second, they are unable to bore cut. Bore cuts allow many more options than simply cutting from one side to the other, whether felling or bucking, and a skilled chainsaw operator uses them constantly. Third, crosscut saws require much more space to operate, which isn't always available. The space is needed because the entire tool moves to do the cutting, instead of just a chain around a bar. They also function much better with two people, and it is often difficult to find footing for the second person, particularly on steep slopes.
Crosscuts are still in use today in the United States primarily because the US Forest Service interprets the Wilderness Act to mean that they cannot use power tools in Wilderness Areas. They require their trail crews to use crosscut saws rather than chainsaws when working in designated wilderness.
[edit] History
Crosscut saws have been in use around the world since historic times, with the design of the saws (the cutting surfaces, the bow and shape of the saw, and the handles) changing over time to accommodate differences in the types of trees being cut, changes in metallurgy technology, and the application of experience. Records exist of crosscut saws in use during the Roman Empire although not widely.[2] They came into wide usage in Europe in the middle of the 15th century. Early saws had a plain tooth pattern until the M tooth pattern was developed in 15th century south Germany. Prior to about 1880 crosscut saws were primarily used for bucking, with axes used to fell trees. Starting in Pennsylvania about 1880, loggers began using the saws for felling trees as well. Despite the modern chainsaw, they are still in wide use around the world, not only in competition matches against chainsaws but also in regular, real-life usage since they afford certain advantages over gasoline-powered saws.
[edit] Vintage saws versus modern saws
There are two types of crosscut saw classification, vintage and modern. Vintage saws are saws that can be anywhere from 30 to as much as 250 years old and are much sought after by professionals, and as such are typically very much more expensive than modern crosscut saws. Modern saws are typically stamped out of sheet metal and are manufactured from contemporary alloys which behave much differently than vintage saws which have historically been made by craftsmen who understood the nuances of the saws they produced.
In September 2005, the United States Forest Service conducted field trials of vintage saws against modern saws, details of which can be found in the external link reference provided below. One significant finding in the background research findings is that vintage saws are becoming increasingly difficult to locate owing to the demand for such saws by professionals.
Overall, modern saws have some advantages over vintage saws such as stiffness which is useful for felling but might cause difficulties when bucking downed trunks which have bind. Vintage saws which bend easily and can, in fact, be folded end-to-end for carrying on one's back, afford easier transport than most modern saws, and afford less-binding cuts that aren't straight.
[edit] Crosscut saw training
Many areas of the National Forests of the United States are designated as Wilderness Areas and as such the use of mechanized and motorized equipment is prohibited except by special circumstance. Because of this, the United States Forest Service (USFS) organizes the crosscut saw training of USFS employees and forest working volunteers in an effort to maintain skills and proficiency among those who need to use such saws.
Training within the Angeles National Forest concentrates greatly upon the safety of the USFS employees and forest volunteers, the safety of animals in the area, and the safety of the surrounding environment.
Training also includes an examination of the differences and benefits of vintage saws and modern saws created with modern materials. Vintage saws are those saws which were manufactured over fifty years ago, being made of high carbon steel instead of the exotic alloys which are typical of contemporary saws.
Crosscut saws are used with a variety of other small hand tools. Wedges are usually used to keep the sections of the log being cut in place as the saw is worked through the rest of the log. Wedges are placed to keep the sections apart but tie wedges may also be applied across the cut to hold sections together until the sawyer is ready for the sections to roll or drop out of the way.
Also covered in typical training sessions is the safe use of the common axe. To keep the saw from cutting through rocks and dirt, the bark of the tree around the area to be cut is often removed with an axe.
Crosscut saw training is mostly safety training with the mechanics of working safely with top bind, bottom bind, and radial (twisting) bind comprising much of the training required to work with such saws. The establishment of escape routes for both felling and bucking may require that both operators at either end of a double-handled saw be constantly aware of the environment around them, and constantly aware of other people within the immediate region which might enter in to the sphere of crosscut influence.
Traditionally over the past 250 years the use of crosscut saws in the many forests of the United States lacked the use of safety clothing and equipment however safety training in contemporary usage in the United States dictates the mandatory use of gloves, eye protectors, chainsaw boots with hard tops and high-top ankle protectors, Kevlar chaps, and long sleeved shirts.
Crosscut saws are used within Designated Wildernesses where chainsaws are banned due to the prohibited use of motorized or mechanized tools and equipment, requiring that crosscut training also include the proper use of non-petroleum based lubricants as well as training in techniques which leave a minimal impact both ecologically as well as visually after trails are cleared of downed trees.
[edit] See also
[edit] References
- ^ http://www.fs.fed.us/t-d/pubs/htmlpubs/htm77712508/page03.htm
- ^ Miller, Warren. Crosscut Saw Manual. Missoula: USDA Technology and Development Center, 1978, p. 2
- Miller, Warren. Crosscut Saw Manual. USDA Forest Service, 1978, published by the U.S. Government Printing Office. Revised edition December 2003.
- Michael, David E. Saws That Sing, A Guide To Using Crosscut Saws. USDA Forest Service, December 2004, published by the U.S. Government Printing Office 64 pages.
[edit] External links
| Wikimedia Commons has media related to: Crosscut saws |
- CrosscutSawyer A forum dedicated to crosscut saw users, filers, collectors and enthusiasts.
- Crosscut Saw Training which took place in the Angeles National Forest on July 25, 2007. Numerous photographs and a description of crosscut saw training is offered.
- Short video of axe being used as an underbuck. The flexibility of the axe handle makes this a preferred method of single underbucking.
- Vintage Crosscut saws
- Field Testing of vintage saws against modern saws
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