Representatives from SpecialtyTools.com, Freud Tools and Super Thin Saws get to the heart of the issue.

Q: How can you increase the life of your saw blades?

Ken Pfister, sales manager and co-host of All About Tools Live, SpecialtyTools.com: One of the most obvious things is to use the right blade for the material you are cutting. That may require more changes in your shop than what you're used to, but it is also an important safety point to adhere to what the manufacturer designed the blade for. Forcing work is another killer, and not only for blades. Just ask the guy with three fingers on one hand and he'll probably talk about bound stock, but what he really means is forced stock. And that isn't good for neither man nor machine. When changing blades, ALWAYS use a piece of wood or wood clamp to hold your blade stationary (after you disconnected the power). By sticking a screw driver or other tool through the gullet, you run the risk of bending a tooth and severely damaging the blade. Finally, don't wait until you can't get your blade through soft butter before you change it. When you start to feel resistance in your cut, change the blade. Otherwise, if you keep running them you'll round over the teeth requiring the removal of more carbide than normal by your sharpener, dramatically reducing your blade life. Also, consider a good blade lubricant.

Cliff Paddock, director of product development, Freud Tools: First and foremost, use the right blade for the task. Freud offers a wide variety of blades with different tooth counts, different grinding geometries and different blends of carbide; all selected to provide optimal performance in specific applications. Using a "crosscut" blade with 80 teeth for a ripping operation, for example, will generate excessive heat and shorten the life of the blade.

Second, keep blades clean and sharp. Using blades with excessive pitch and gum buildup creates excess heat, which may burn the workpiece and cause carbide tips to lose their edge more quickly. A similar situation results from dull teeth. Forcing a dull blade creates heat, is unsafe, and it can lead to chipping a tooth. Once a tooth is chipped the blade will require more grinding to resharpen.

Finally, inspect the workpiece for defects like nails, staples and loose knots, which can damage the blade and put the operator's safety at risk.

To sum up, remember that heat is the worst enemy of your saw blades. Dull, dirty blades — or blades with too many teeth — create excessive heat and decrease blade life.

ohn Schultz, president, Super Thin Saws: Make sure the arbor and feed works are properly lined up. Any misalignment results in increased back-cutting, which accelerates tool wear (and also decreases cut quality).

Coating to prevent pitch buildup: In many applications, the blades need to be removed from the arbor several times between sharpenings so pitch buildup can be removed from the sides of the saw body. This can be alleviated greatly by appropriate coating on the sides of the saw blade. I am not a big fan of Teflon coatings or chrome platings, but consult your own, trusted, saw blade supplier for guidance on what coating may be more appropriate for your application.

Spray mist coolant/lubricant: Coolants and lubricants can be very effective. The choice of coolant is very important, as is the choice of application method. Once again you should consult a trusted supplier.

Coating the cutting edge: Coatings such as titanium nitride are very popular and effective in metalworking tools, but I have never seen any benefit in woodworking saw blades. Hopefully some day a new coating will come along, but for now this seems to be only for metal working saw blades.

Harder carbide: When your blade is dull, look at the tips under a magnifying glass. If they look rounded, a harder grade of carbide will help them to last longer between sharpenings by wearing more slowly. But harder carbides are more brittle.

Tougher carbide: If your teeth appear to have lots of little chips (or big chips) on the cutting edge, instead of a smoothly worn round surface, then you need a tougher carbide which actually means that a less hard carbide will run longer for you, because you are currently chipping the cutting edge off before it can become dull.

Q: What are the benefits of carbide-tipped blades? Are there disadvantages?

Pfister, SpecialtyTools.com: My favorite thing about carbide is that it holds its edge for a good while. Ever try a high-speed steel blade? The few times I have used them, I was lucky to get 10 to 12 good cuts before I could feel my cutting deteriorate. Plus you can have carbide resharpened, repeatedly, depending on the quality of the blade you purchased. I always try to find out the type of carbide on the blade and pay attention to how much they give me. Straight-up steel blades are cheap, so most guys just throw 'em out (though I have seen a few frugal guys go at them with a file). The thing is this: unless you're a framer that drops his saw in the dirt half the day, which could knock off carbide teeth, you'll be better served by having a blade which will maximize the performance of your tool by giving you smoother, cleaner and safer cuts. Remember, tools are often cheaper than labor. So anything that makes my labor more productive leaves more money for me at the end of the day.

Paddock, Freud Tools: Carbide is much harder and more resistant to abrasion than steel, so it delivers longer life in virtually any cutting application. In the early days of carbide-tipped tools, there was the perception that high-speed steel teeth could be honed to a keener edge, and consequently produce a cleaner cut and better finish. Carbide technology has come a long way, however. Freud's TiCo Hi-Density carbide now features special blends of titanium carbide and cobalt that can be ground to extremely fine edges that rival the highest quality steel teeth. Equally important, these special blends hold their edges many times longer than even the best high-speed steel.

Freud's TiCo Hi-Density carbide also provides the advantage of being offered in application specific blends. For example, highly abrasive materials like laminates and melamine are matched with abrasion-resistant blends of carbide. Nonferrous metals, on the other hand, are cut with carbide mixtures better suited to resist impact. This flexibility is a significant advantage of Freud carbide vs. high-speed steel or inferior carbides.

Schultz, Super Thin Saws: The historical saw blade, that carbide originally was "an alternative to," was a tool steel disc, with teeth ground into it. This is very tough, but not very hard, so it dulls much more quickly than carbide in most applications and is no longer very much used industrially. Some alternatives are:

• High-speed steel — In between tool steel and carbide in terms of hardness, high-speed steel saw blades still have applications in some fields, but not particularly for cutting wood.
• Carbide, various grades — The various grades of carbides have become by far the most common materials for cutting edges of industrial saw blades for woodworking. There cost/benefit ratio is far ahead of all the alternatives for most applications, but some of the newer, more exotic possibilities are making inroads for certain, specialized purposes. If a saw blade has to do more than one thing, it is almost certain that carbide is the best bet.
• Casts alloys — These are softer than carbides, but still quite hard, and the cobalt is bound in differently. Because a significant part of the dulling mechanism is chemical, this difference can mean that, in certain species of wood, these materials run longer than carbide. Once again, the best advice is to consult a trusted supplier.
• Cermets — Cermets are harder than carbide and more brittle. If it were that simple they would already have taken over a significant market share from carbide. Unfortunately, there have been significant brazing and grinding difficulties which have delayed that, but this is a cutting-edge material that may be right on the horizon.
• Polycrystalline Diamond (PCD) — This cutting-edge material is much harder than carbide, but it has limitations due to price, brittleness and limitations on the included angle. Nevertheless it has obliterated carbide in certain market niches where it works well. If the price continues to drop, this cutting-edge material will steal more and more market share from carbide.
• Even more exotic — There are also more exotic materials such as monocrystalline diamond and polycrystalline cubic boron nitride. And of course some woodcutting applications can be done without saw blades using waterjets or lasers, etc. None of these is much of a threat to the dominance of carbide saw blades in the next decade, but in the long run, who knows?

Q: How does tooth count influence a blade's cut? How can you ensure you are picking the correct tooth count for your application?

Pfister, SpecialtyTools.com: Here's the important stuff, and it's not just about teeth. A blade represents a package, but here's something to chew on: more teeth = slower, smoother cut and more heat; less teeth = faster, coarser cut with less heat buildup. What about tooth shape and configuration? ATB, MTC and 4&1 are just a few; just make sure you know which one you need or ask if you're uncertain. Here are some other performance questions that must be answered. What is the hook or rake angle of the teeth? The greater the angle, the more the material is pulled into the blade. A negative hook and the debris is pushed away from the blade. With a positive hook how large is the gullet and can it hold the debris from your cut until it can be thrown off? If not, heat will be your enemy. Does the plate have expansion slots, those usually four straight or squiggly cuts? That makes a big difference in how your blade will deal with heat preventing potential cracking in the plate. What about the shoulder, that area behind the tooth? Does it look solid or small and weak? Finally, I prefer a laser cut body over a stamped one. It is less likely to have a deviation in the plate from manufacture and clean rotation is so important with a blade. With all this, we've only scratched the surface.

Paddock, Freud Tools: Matching the correct number of teeth to the cutting application is vital to any blade's performance. There is a critical misconception among some woodworkers that "more teeth are always better." In fact, too many teeth — or too few — can dramatically affect the quality of cut and the life of the blade.

For example, on a 10-in. diameter blade, 24 to 30 teeth are ideal for ripping applications because the spacing of the teeth and the size of the "gullets" between the teeth allow for rapid ejection of chips and dust. This allows the blade to cut efficiently with less buildup of heat. If this ripping blade had 80 teeth, however, the chips and dust would tend to build up in the cut and between the teeth. This buildup of debris leads to unacceptably high heat and slower cutting action, which burns the workpiece and shortens the life of the blade. For crosscutting applications, however, 80 teeth are an ideal choice for producing high-quality cuts with a 10-in. blade.

Schultz, Super Thin Saws: Chip thickness: Cutting edges dull much faster with too much heat, and by far the biggest share of the heat from cutting wood is carried away by the chips — in this case sawdust. (This is why your sawdust is warm.) If the "tooth bite" is too small, the springback in the wood means you get powder (or even just rubbing) instead of real chips and you will see a burnished surface on the wood. If your chip thickness is too great you will have difficulty producing a good surface on the workpiece. (This is because the chip itself has too much structural integrity.)

The ideal chip thickness is different for different types of cut.

Green wood should usually have thicker chips than dry wood (because the compressibility is greater and the structural integrity is less).

Similarly ripcuts can have thicker chips than crosscuts.

The exact answer is different for different species, but you should be able to measure your chips with a micrometer and find that they are several thousandths of an inch thick.

You can calculate in advance what they will be from the number of teeth and some other parameters (feed rate, rpm, saw blade protrusion, depth of cut, and even grind style.) This gets quite technical and once again, you may want to consult a trusted source. It should be added, however, that the number of teeth used for different applications is something that has evolved over time to achieve best performance, so if you are doing something fairly common, the "normal" number of teeth is probably best.