Sharp teeth resist loads and increase cutting speed - cutting speed and finish depend on material thickness and teeth per inch. The thicker the object being cut, the thinner the blade should be - Size 1, 2 and 3 blades are recommended for sawing metal - Sizes 4, 5, 6 and 7 are good for sawing wood - Size 8 can be used for sawing plastics. Forged from carbon steel - Finish machined - High hardness and strength - Hardened to stay sharper longer. Easily replace damaged or worn saw blades. These blades saw all around with 360 degree cutting capability - arc sawing is easy and the blade won't jam - great for wood cutting and shaping, jewelry making, metalworking, crafting and more. To install the saw blade, insert the saw blade into the small hole on the .