3 Tooling and Blade Selection
Almost exclusively, modern table saw blades have teeth made of tungsten carbide, a chemical compound containing equal parts tungsten and carbon. It is approximately twice as stiff and double the density as steel. Carbide can cut all wood products, dense composite materials such as Corian™, and non-ferrous metals such as brass, copper and aluminum. Carbide is extremely hard, therefore it maintains sharpness over a long period of use in the woodworking shop. The flip side of this extreme hardness is that it is brittle.
- Use care when installing the saw blade not to touch the teeth to the surrounding saw casting.
- Do not set saw blades down directly on the cast iron saw table.
- Do not place carbide cutters of any kind in contact with each other- they can dull and chip easily.
- Use a dedicated saw blade holder, or use a protective layer between the blades. A simple square of cardboard can work.
Carbide is too hard to sharpen without diamond tooling, and modern saw blades are highly accurate cutting tools. When carbide blades require sharpening, they are sent out to sharpening service. Most companies use CNC (computer numerically controlled) technology to sharpen the blades.
Selecting the correct saw blade is critical to safe use of the table saw as well as obtaining a quality cut. Table saw blades fall broadly into five categories: crosscut, triple chip, rip, combination blades (simple & planer style), dado cutters and moulding heads. Knowing the components that make up a blade and understanding the geometry will allow you to select the correct blade for the cutting operation.
Saw Blade Components
While the geometry of circular saw blades varies, they are comprised of the same basic components.
Plate
The plate comprises the main body of the blade. It may be stamped or laser cut. Laser cut blades are more expensive, the quality ones are very flat and stable and run quieter than stamped blades. In both types of blades, the plate must be flat and true to produce accurate cuts and prevent excessive noise. All plate bodies are thinner than the teeth to provide clearance to the work piece, some also have a friction reducing coating such as Teflon™. The hole in the blade that allows it to mount on the arbor shaft is called the bore. Common arbor sizes are 1/2″, 5/8″, 3/4″, 7/8″, 1″, 20 mm, 30 mm, and 32 mm. A 5/8″ arbor is common on portable, contractor and cabinet table saws sold in Canada.
Expansion slot, termination hole, metal filler
Saw blades heat up in use due to friction, heat causes the plate to expand. To prevent the plate from warping, most blades have expansion slots to allow for expansion without impacting the performance of the blade. The termination hole at the bottom of the slot reduces stress on the surrounding metal. In some blades, the termination hole is filled in with a soft metal such as copper which helps reduce noise.
Gullet
The gullet is the space between the teeth of the blade, it has a smooth roun