Circular Saw Blade Selection
Not too long ago, circular saw blades were just simple steel discs with some teeth around the rim. Now, blade technology has advanced to strong teeth with carbide that will stay sharp longer. The blade body sometimes has laser-cut slots to reduce friction, noise, and distortion from heat. Some go further and have special coatings to reduce friction even more.
What to Know
Because of the technological improvements, the body of the blade is now more stable, and manufacturers can reduce the thickness. This is the era of thin-kerf blades.
While you may not think a thinner cutline makes much of a difference, it creates many benefits, like saving wood and reducing dust. However, the most important benefits are being able to boost cutting power and still use the same horsepower. This benefit has made possible a new generation of cordless circular saws.
The advancements in metal technology of using bi-metals are not just limited to circular saw blades but now included jigsaw and reciprocating blades. Steel by itself is hard but brittle. However, by combining a flexible backing through a laser or electron welding produces an edge superior to one made from only one material. These new bi-metal blades usually last three times as long as conventional blades. If you’ve ever had to change a blade on a circular saw, you know you’d slightly be cutting material instead of doing maintenance.
To make it simple, here are the recommendations of blades for your shop. The choice of blades is finding a workable balance between the need for speed and the quality of the cut. A blade with fewer teeth will cut more aggressively and not leave a smooth finish. Conversely, blades with high tooth count usually produce a smooth cut if the blade is sharp. However, if the blade is dull, you could get burned edges.
For framing jobs or rough cutting, use a carbide-tip blade that has 18 to 24 teeth. This works best for 7 1/4, 6 1/2- and 5-inch cordless saws.
If you’re working on demolition jobs, you might strike fasteners embedded in the wood, so you’ll need a blade designed for nail-cutting. If you’re building a deck and working with wet pressure-treated wood, select a blade resistant to bogging down. If you want a smooth finish from cuts in solid wood or plywood, choose a blade with 36 teeth. Steel blades are not entirely obsolete; I can still use them for rough carpentry work.
How Many Teeth Should Your Circular Saw Blade Have?
Every woodworker wants to get the smoothest cut possible with their table saw; miter saw or circular saw. While common sense might tell you that a blade with more teeth will produce a smoother cut compared to another blade with fewer teeth, the truth is a little more complicated. However, after you understand how the teeth on a saw work, the answers become a little clearer.
The more teeth, the smoother the cut. It doesn’t matter if you’re calculating the total number of teeth on the blade or the teeth per inch. Blades with fewer teeth produce rougher cuts because there are deeper gullets in between the teeth that accumulate sawdust until the related tooth clears the blade.
Blades with more teeth have smaller bullets in between the teeth; this makes the cuts slower and less aggressive. The problem with slower cuts is that it increases the possibility of burning the wood during cutting. If the sawdust has difficulty clearing, the blade friction increases and becomes more likely to bind.
The solution is to keep several types of blades on hand. As an example, a 40-tooth blade is useful for the general with your table or circular saw. An 80-tooth works better for plywood and veneers, and a unique ripping blade is best for making rip cuts.
For a band saw, there is a variety of blades designed to function best depending on the sharpness of the curves being cut. Start with a ¼ inch blade for making tight curves, then use a ½ inch band for across-the-board cuts. Move up to the ¾ inch for resewing.
Blade maintenance is essential to producing nice clean cuts and for protecting your investment. All blades will soon become covered in pitch—this is a sap from the wood that builds up. This pitch accumulation will cause the blade to heat and will dull the teeth.
One way to keep your blades in good condition is to clean them regularly with a cleaning solution designed to remove pitch. Your local woodworking supply store should have this product. Use none abrasive cleaners because they can scratch the surface of the blade. These minutes scratch make the problem worse since they will soon fill up with the pitch.
Now for another handy tip with a standard household product; soak your blades in oven cleaner. It’s non-abrasive and removes tough stains that are baked on. When you think about it, this baked on stain is precisely what happens to sap as it builds upon the blade and gets heated by friction during cutting.