Bent Blades

• To effectively sharpen a blade, the blade itself must be straight. Using a saw can cause the blade to become bent or kinked. These irregularities must be removed before a blade can be effectively sharpened.
  
  

Crooked Teeth

• The teeth, or the points along the saw blade that cut the wood, need to be straight for the process of filing and sharpening to be even and effective. Using a saw can cause the teeth to bend, despite the shape of the saw blade itself. These teeth need to be pounded back into place before sharpening.
  
  

Oversized Teeth

• When a saw blade has some teeth that are longer than others, this can cause the same problem with the filing motion as with crooked teeth. The over-sized teeth must be individually filed down to size to effectively sharpen the entire blade.