Even the best saws will produce a poor cut if you aren't using the correct circular saw blade for the job. I want to show you the different aspects of the blade that will hopefully produce the results you want from your saw.
Carbide-tipped or High Speed Steel The cutting edge on saw blades is made from either carbide or steel. Carbide-tipped blades have almost completely replaced lesser quality steel blades. The biggest difference between the fact that carbide will last longer with out losing its edge. A carbide edge is said to last up to 50 times longer than steel before it needs to be sharpened. This is the reason almost all serious woodworkers, amateurs and pros, choose carbide over steel. A good carbide-tipped blade can cost around five times the amount of a good steel blade. In the long run carbide is still cheaper when you think about the amount of time and money spent having to constantly sharpen, send out to be sharpened, or buy new steel blades. The only real drawback to carbide is the fact that you have to be especially careful when using and storing them. They are extremely brittle and are easily chipped when bumped against steel or other carbide. Carbide-tipped blades are nearly impossible to sharpen yourself so it's a good idea to keep two of each. This way you'll have less downtime when you send them out to be sharpened. Number of Teeth The more teeth on a blade the smoother the cut will be. The downside to this is the more teeth you have cutting into the wood, the more pressure it will take to feed your piece through. Ripping wood requires fewer teeth than does making a crosscut. When general ripping on hardwoods, a blade with 24 teeth is usually enough to provide a clean cut. Crosscutting requires more teeth because it is more likely to chip and score the wood without more teeth. With that in mind, look for a blade with around 60 teeth for crosscutting. Plywood requires a tooth count of 60 to 80 to produce a clean cut. Tooth Configuration The tooth configuration is used to describe the way the teeth are ground. For the purpose of keeping this simple, I will describe the three main types of tooth grind you will likely see. Flat-top (FT)- The flat-top tooth is the simplest of the three. Just as the name suggests it has a tooth that is flat or squared. It is used to quickly remove material. This is the type of blade to use for general ripping. Alternate Top Bevel (ATB)- ATB teeth have a bevel on the blade that changes from left to right on each tooth. They will give you a smooth cut, but remove less stock than the FT tooth. This should be your choice for a crosscut blade. Triple Chip or Triple Chip Grind (TC or TCG)- TC teeth have both a beveled teeth to make a clean cut followed by flat-top teeth to clear stock. These are used for cutting hard materials like laminates and also for plywood panels. Hook Angle The hook angle is hard to describe, but I'll give it a shot. Think of the rotation of the blade. If you were to draw a line from the center the blade to the tooth and the actual cutting edge lined up with this line the hook angle would be a 0 degree hook angle. If the cutting edge were over the line the blade is said to have a positive hook angle. If it were behind the line, a negative hook angle. Hopefully in the future I can get some pictures to add here to better describe this. A higher positive hook angle has a faster, more aggressive cut. The problem with this is you're more likely to see splintering on the bottom side of you piece. A lower or negative hook angle will have a slower cut but are less likely to splinter. When buying a blade for a table saw you should look for one with a high hook angle. +20 degrees for ripping and +10 degrees for crosscutting. The exception is for a blade meant for plywood and plastic laminate. A hook angle of around +5 to -3 degrees is needed. When getting a blade for a radial arm saw or miter saw that is mainly used for crosscutting look for a -5 degree hook angle. Cost Okay so you know what type of blade you need, the hook angle, and so forth but why do the prices vary so much. A 10" carbide tipped blade can cost anywhere from $5 to $200. So what's the difference? There are three different grades of quality in circular saw blades: consumer or economy grade, contractor grade, and industrial grade. Consumer blades are the lowest quality blades and prices range around $5 to $20. The tolerances on these are the loosest and should only be used for general carpentry work where precision isn't a major factor. The teeth cannot be sharpened which is why they are also known as disposables. Contractor blades are made from better materials and are produced with higher tolerances. The prices of these range from $25 to $50. Be sure to examine them for defects before using them because they are mass produced. Industrial blades are made from the best materials with the highest tolerances. They should last longer between sharpening and produce the most precise cuts needed in fine furniture making and cabinetmaking. Look to pay anywhere from $50 to $200 for these.
