part that supports the motor and blade. When you change the blade angle, the guard also tilts. The assembly consists of the blade guard, splitter, and anti-kickback pawls. The guard rests over the blade and is hinged to the splitter. The splitter keeps the saw kerf open as the cut is made. Without a splitter, stock that warps during the cut could squeeze against the blade and bind the saw. The stock might then be thrown back toward you. With a splitter-type guard, you must saw completely through the material. If the material binds, anti-kickback pawls, attached to the splitter, should prevent the material from being thrown back at the operator. The pawls ride on top of the stock after it passes the blade. If the material binds during the cut, the pawls dig in to stop it from being kicked back. If the material becomes difficult to feed, hold it against the table with a push stick or by hand. With your other hand, reach down and turn off the power. Wait until the saw stops to remove the material. An overhead guard attaches to the edge of the saw table. See Figure 23-5. It is adjusted inde- pendently of the blade. This type of guard may be used with either a splitter or a riving knife. A riving knife is a curved, steel plate mounted behind the blade. The knife functions much like a splitter except that it is not equipped with anti-kickback pawls, Figure 23-6. Riving knives are preferable because they are less obtrusive and can remain in place when cutting grooves. Riving knives must be properly adjusted to function correctly. They should be approximately 1/16″ (1.5 mm) below the top of the blade, and slightly thinner than the kerf. 23.3.3 Installing Saw Blades Circular saw blades are categorized by tooth design, kerf width, arbor hole size, and other fea- tures. The blade may also be categorized according to the grain direction or material it cuts. For exam- ple, a rip blade is designed to cut along the grain. A crosscut blade is designed for cuts across the grain. Combination blades do both. A more detailed dis- cussion of blade design and selection is given later in the chapter. Acacia Figure 23-5. Blade guards may be mounted to the table edge. Saw Blade Installation Install saw blades as follows: 1. With the switch off, disconnect the power and lock out the machine. 2. Remove the table insert (and blade guard, if necessary). 3. Raise the blade so the nut on the arbor can be reached easily. 4. Some saws have arbor locking mechanisms, while others use a double wrench system, Figure 23-7. If your saw has neither of these, place a wrench on the nut and wedge a piece of softwood in between the blade and the saw’s surface to loosen the nut. 5. Pull the wrench toward the front of the saw to loosen the nut. 6. Remove the nut, arbor washer, and blade. 7. Remove any pitch, gum, or rust from the arbor, flange, arbor washer, and nut with solvent and fine steel wool. 8. Install the replacement blade with the teeth pointing toward the front of the table (in the direction of blade rotation). 9. Install the arbor washer and thread the nut on finger-tight. 10. Tighten the nut with the wrench. While standing behind the machine, push the wrench toward the back of the saw table. Use the arbor lock, wrenches, or wedge a piece of softwood lumber between the blade and the saw’s surface to keep the blade stationary. Be careful not to damage the teeth on the blade. 11. Replace the table insert and guard. Procedure Chapter 23 Sawing with Stationary Power Machines 375 Copyright Goodheart-Willcox Co., Inc.