Number of Teeth

• The number of teeth your saw blade should have will, like all the other factors in picking out a saw blade, depend on your cutting needs. In this case the question is, do you want it fast or clean? A saw blade with few teeth will meet less resistance as it turns, meaning you can buzz through wood planks at a ridiculously fast pace. The downside is that the cuts will be ragged and filled with splinters. A saw blade with more teeth will cut slowly, but the cut will be clean and smooth.
  
  

Gullet

• The gullet is defined as both the width and depth of the space cut into the blade between its teeth. This concerns the rate at which wood chips and saw dust clear from the blade before it can bite into the wood again. If you're sawing logs into planks at a sawmill then the gullet needs to be very big, because there will be lots of wood chips to get in the way. If you're cutting small pieces of wood, like house siding or plywood, then the gullet should be smaller. If the gullet is too small, then it will cut slower and may even jam. Anyone who's had a table saw jam knows how dangerous that can be as the wood bucks and jerks out of control, caught by the blade. If the gullet is too big, then it may reduce the overall cut speed, as well as leave the wood with jagged edges.
  
  

Configuration

• There are four common tooth configurations. The flat top tooth is best for rough cutting lots of wood quickly, ripping through wood and clearing it from the saw quickly. The downside is that it doesn't cut cleanly, leaving a serious need for refinement after the initial cuts. Alternate top bevel is a combination configuration in which one tooth faces to the left and the next faces to the right, and so on. This type cuts equally well for just about any use, not good, but not bad. The hightop alternate bevel type blade configuration is very sharp, being designed to cut as cleanly as possible. The downside is that it's very slow because it can't clear wood chips very quickly. The triple grind chip configuration is designed to cut plastics, Formica and other non-wood building materials. It's very strong, but can't clear away wood chips, so it shouldn't be used on materials that tend to splinter.
  
  

Hook Angle

• The hook angle is the angle at which the cutting edge of the blade's teeth sit if one were to draw a line radiating out from the center of the blade. This value is expressed in terms of positive and negative hook angle. A positive hook angle is one where the teeth sit, seeming to lean forward. A blade with high positive hook angle will cut very fast and aggressively. The downside is that such blades can be dangerous. They pull the wood forward across the blade with their own ripping action, which can result in injury to the operator. If they jam, catching on a knothole for instance, they tend to kick the wood backward violently, again resulting in injury. A blade with a negative hook angle is more controllable. It does not pull the wood, nor does it kick the wood back if it jams. It cuts more slowly, but by being more controllable the end result is typically a much cleaner and more satisfactory cut.