23.10.3 Scroll Saw Blades The scroll saw also uses several different blade types. See Figure 23-62. Standard blades cut in only one direction. They vary in width and number of TPI. Common widths are 1/8″–1/4″ (3 mm–6 mm). Scroll saw blades typically have 7 to 20 TPI. They have beveled teeth that are alternately set. Normally, at least three teeth should contact the material at all times. A 7 TPI blade would be best for soft lumber with high moisture content. A 20 TPI blade, about 1/32″ (1 mm) wide, is proper for veneer and other very thin material. The standard blade length is 5″ (127 mm). In addition, a round blade with spiral teeth is available. You can move the material in any direction while cutting. Flat, abrasive-coated blades, 1/4″ (6 mm) in width, are available for sanding inside corners. 23.11 Maintaining Saw Blades Saw blades should be sharp, free of rust or resin, and with all teeth intact. Inspect blades frequently for cracks (especially in the gullets), warp, bluish color (sign of overheating), and missing or damaged carbide teeth. Proper maintenance may include cleaning and sharpening or discarding. Clean blades with a solvent such as paint thin- ner. Oven cleaner may be used on more stubborn resins. Wear rubber gloves to protect your hands. Rust can be removed with oil and fine steel wool. Remove the oil and coat the blade with paste wax or silicone spray before storing it. Carbide-tipped blades cannot be hand sharp- ened. Machine grinding with a diamond wheel is the only method to sharpen a carbide-tipped blade and is best left to a professional. 23.12 Maintaining Power Saws Maintaining stationary power saws properly will increase their usable life. Inspect, clean, adjust, and lubricate saws periodically. The machine must be disconnected from electrical power and locked out before servicing. For complex repairs, refer to the owner’s manual. 23.12.1 Table Saw Table saws should accurately cut material. If you check a workpiece and find it out of square that could indicate a table, miter gauge, or fence problem. Imagine you are sawing using the miter gauge. You notice the workpiece pulls away from or feeds in toward the blade. The miter gauge slot may not be parallel to the blade. Check this by comparing read- ings with a dial indicator, Figure 23-63. The dial should not move as you slide the miter gauge. (Be sure the blade is not warped. Install a new blade or a flat steel plate.) To correct this problem, loosen and turn the tabletop slightly. Now imagine you are sawing using the rip fence. The workpiece pulls away from or rubs tightly against the fence. This indicates the fence is out of alignment. If the fence was dropped at some point, one or more locking mechanism bolts or nuts may have slipped. Loosen them, move the fence to align it, and then retighten the bolts or nuts. Goodheart-Willcox Publisher Figure 23-61. Band saw blades shapes and sets. Goodheart-Willcox Publisher Figure 23-62. Scroll saw blades. R a k e r W a v y A l t e r n a t i v e R e g u l a r H o o k S k i p Sets Shapes Straight Blades Skip-Tooth Blade Skip-Tooth Reverse Blade Double-Tooth Blade Spiral Blade Chapter 23 Sawing with Stationary Power Machines 403 Copyright Goodheart-Willcox Co., Inc.