Today there is an increasing use of specialty saw blades commonly referred to as "thin saws." The vast majority of all saw blades used in the secondary woodworking industry have diameters ranging from 10 to 16 inches. Common cutting width (kerf) will measure from 0.125 inch for light to moderate crosscut and trim work to 0.180 inch and larger for heavy workloads in more difficult materials. Thin saws are seldom larger than 10 or 12 inches in diameter, but for unique applications can have cutting widths as small as 0.040 inch (1 mm).
Nearly all thin saw applications in the industry are for stock yield, or making numerous little parts from a larger one. The most successful stock yield applications are done on precision automated machines such as feed-through moulders.
One of the advantages to using thin saws is the direct relationship between cutting width and the amount of horsepower needed. For example, using a narrower kerf requires less energy. In addition to energy savings, greatly improved stock yield increases efficiency and profitability.
There are clear and distinct advantages to using thin saws, but at the same time the operating conditions are fairly strict and there are precautions to be aware of. There is not an "all-purpose" thin saw for industrial use, which reduces its range of task abilities. The tools used with thin saws require special means for holding and transmitting needed horsepower, and only clean, known, and clearly defined materials can be cut successfully. While horsepower usage and the machining process of the cutting tools is not an obstacle, clamping and feeding the workpiece material proves to be the greatest problem to resolve.
There has always been demand for saw blades with very thin cutting widths, both to save material as well as reduce horsepower consumption. However, reducing plate thickness introduces problems with maintaining blade strength, rigidity, and operating life. In the past 50 years, tool makers in the U.S. and Europe have invested a great deal of time and expense to research and improve their knowledge of the relationship between plate thickness and cutting width of carbide-tipped saw blades.
Nearly 30 years ago, a university metallurgist discovered that steel saw plate bodies could be made stronger, straighter, and have a longer useful life if alloyed with high percentages of nickel. Although his discovery is true, it made the cost of the tool greater than any possible savings that such a tool would yield. The answer to the problem was not found in expensive alloys, but instead was resolved by widening understanding of basic alloying methods, heat treatment, and steel tensioning.
Today, thin saws are precise and capable of a fairly wide range of work tasks if they are well supported on vibration-free arbors and the workpiece is clamped and fed accurately. Still, the ideal operating conditions are far more stringent than tools with conventional plate thickness. The geometric features of thin saws are similar to others, except that they are miniaturized. The cutting and back relief angles are largely identical to others cutting the same material, but the lateral relief to the periphery angle is a bit shallower because it is so small to begin with. Hence, the lateral clearance distance is proportionally smaller.
Because thin saws are used in nearly all applications to cut clean homogenous materials, the assumption might be that sharpening life should be somewhat longer. Unfortunately, sharpness is so critical to proper operation that the blades need to be sharpened more often.
Transmitting the motor horsepower to the thin saws is another critical issue, though not a difficult one to solve. Unlike their heavier counterparts, even the normal bore-to-arbor tolerance may cause an unstable operation. To date, the most successful use of a thin saw incorporates a set of tools mounted to a hydraulically clamped sleeve. Straight, smooth sleeves can also be used in certain applications, but do not provide great precision and ease of operation.
The selection and monitoring of the material to be cut with thin saw technology is as important as any other element. Natural wood species that are particularly dense and strong can be bothersome, especially if the grain orientation wanders, has unusual stress factors, or would cause lateral stresses in the cutting process. Monitoring the wood's moisture content is also a critical issue, though it is perhaps the only variable of its nature that can be controlled with any accuracy.
Thin saws have relief features similar to other saws. Back relief, lateral, and lateral-relief-to-the-periphery may be modified to suit a particular outcome such as finish quality or a desired feed rate. Because of their narrow construction features, the lateral clearance distances are proportionally smaller, allowing only enough tooth material to provide adequate sharpening life and support the cutting process.
Feed rate for thin saw applications is the easiest characteristic to modify. Beyond assuring that the tool holding systems are precise and the stock clamping/feeding mechanism are free of any movement, the feed rate is the most tangible variable to adjust. For example, if the material has too much internal stress or causes lateral blade movement, we can either slow the feed rate or use a heavier saw.
All cutting tools and machining processes can be modified in some manner to satisfy a particular outcome. Cutting tool features can be made to any workable configuration, machines can be made to go faster or slower, and all can be made with more precision and attention to detail. Thin saws are perhaps the only cutting tools that come so close to being completely over powered by the material being cut. This technology has many advantages, but its application must be well thought out before it is set into motion.
I wish to thank John Schultz and the technical staff of Super Thin Saws, Inc. for their input into this article. For more information on specific uses and applications of thin saws, contact them at 800/541-7297.
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