I once let the smoke out of a portable table saw while ripping 2-by. The saw was powerful enough and the blade was new. Unfortunately, it was a miter saw blade and its 60 or so teeth had the wrong rake angle for the task at hand.
Since then, I’ve paid more attention to the blades I put on my tools. Now I make sure to get the best one for the job–whether it’s an old, thin-kerf 7-1/4-inch blade for cutting through a roof, or a new $100 Teflon-coated blade for my miter saw.
Stationary table saws: Fairly thick .125-inch kerf combination blades with between 50 and 70 teeth are usually considered best for woodworking. These blades’ tooth configuration (three alternate top bevel [ATB] teeth followed by one raker tooth) cuts smoothly across and with the grain. The stiff blade plates prevent flexing and vibration in tough materials, which might occur with thinner-kerfed (.097-inch) blades.
If you’re cutting lots of different materials like MDF, melamine, and hardwoods, a triple chip grind might be for you. The teeth on these blades can handle the brutally blade-dulling MDF, then cut through hardwood without a hiccup. The trade-off might be some cut speed, but you gain a smoother, more effortless cut without a blade change.
Chop and sliding mitersaws: Chop saws and sliders use the same blade design. Most people use — and most manufacturers suggest –an ATB tooth configuration. More teeth (80 to 90-plus) typically means a smoother, cleaner cut, especially in hardwood and synthetic moldings. For a blade that’ll really help prevent tear-out, try one with raker teeth. The raker teeth help clean the cut out so the ATB teeth cut better. Expect to pay around $100 for blades like these.
For fine work, use a thick blade plate (.110-inch) on your miter saw. Less expensive thin-kerf blades can deflect in big pieces of trim, especially when you’re just trying to shave a hair off. Teflon-coated blades significantly limit the amount of pitch that builds up on your blade plate and teeth over time. Use the 40-tooth thin-kerf blades for your framing jobs.
Circ saws: There are really two schools of thought here: use-and-destroy or use-and-maintain. The use-and-destroy school recommends buying a lot of thin-kerf blades (.059-inch) cheap and throwing them out when they get dull. When they’re new and sharp, they cut fast. If you hit a few nails, though, that’s it. At less than $10 a piece, that’s not a big deal.
Other carpenters think a thicker-kerf blade (.091-inch) that you can maintain is the right choice. The thicker blades have bigger carbide teeth; they hold up to nails better and you can re-sharpen them to keep them in your fleet longer. However, you’ll pay more for them–upwards of $25.
If you want straighter cuts and rips or if you’re doing any kind of fine work like using a shoot board to cut built-in parts, stay away from thin-kerf blades–especially dull ones. Even sharp thin-kerf blades can deflect and leave you with a lower quality cut than a stiffer, thicker-kerf blade. Many thin-kerf blades have aggressive hook angles (20 degrees or so) for faster cutting, but they can add to tear-out. Combination blades generally have lower hook angles of about 12 degrees and exit the work more cleanly.
Metal cutting saws: There are two blade choices for cutting metal: an abrasive wheel and a dry-cut, carbide-tipped blade. Once you use a dry-cut blade, you’ll never want to see an abrasive wheel again. Dry-cut blades cut faster and smoother than abrasive wheels, don’t leave burrs, and don’t heat up the material. These blades are made from the same materials as wood-cutting blades, but the teeth and carbide are configured differently. Ironically, the C-6 carbide for cutting steel is softer than the carbide for cutting wood, and the blade teeth are positioned with a negative hook angle to strike the material differently than wood-cutting blades do.
You’ll find 36 to 48 teeth on 7-1/4-inch circular saw blades. Be careful though, because there are blades for wormdrives, sidewinders, and metal-specific saws, as well as for ferrous and non-ferrous metals and stainless steel. A 12-inch blade designed for a 1,700-rpm dry-cut metal-cutting saw has 60 to 90 teeth. Material-specific blades cut soft metals (light-gauge metal studs, aluminum) or hard steel (angle, black pipe, or stainless steel) almost as easily as wood-cutting blades slice wood. You may be tempted to cut wood with these blades, but it’s not a good idea. You can make a few cuts, but wood dulls the soft carbide quickly on these blades.
There’s a new blade for circ and miter saws that claims to cut it all –wood, light metals, and plastics –without dulling inordinately fast. First Edition Products’ Universal blade comes in 7-1/4-, 8-, 10-, and 12-inch diameters.
Cordless tools: For cordless saws, there isn’t much of a choice for blades kerf-wise; they’re all thin. Thin-kerf blades take a smaller bite out of the wood as they cut; toolmakers rely on this to maximize their batteries’ output. Vermont American recently introduced blades specifically designed for cordless circ and recip saws that the company claims will maximize tool performance and out-cut other thin-kerf products.
Portable table saws: Thin-kerf ATB blades are the answer here for cutting jobsite materials fast. Portable table saws’ smaller motors perform better with thin-kerf blades because they don’t have to work as hard to push the teeth through work. But don’t expect cabinet-quality joinery out of these blades. They can deflect more easily than a thicker-kerf blade, especially when material is wet, warped, and you’re working with a short fence and no outfeed table. You can minimize this by installing blade stabilizers on the saw arbor.