How to Choose the Correct Number of Teeth Per Inch (TPI)
The number of teeth per inch (TPI) is important in obtaining the finish desired and the proper feed rate. A coarse tooth blade (1, 2 or 3 TPI) should be used for re-sawing wood and cutting thicker stock. A fine toothed blade (18 to 32 TPI) should be used for thinner metals and plastics under 1/4". For general cutting of 3/4" plywood 4 or 6 TPI will provide a fast cut and 14 TPI will cut much slower but leave a smooth finish on the cut. As a general rule, try to have 3 to 12 teeth in the work for general cutting. Bandsaws designed to cut wood runs at 2700 to 3200 band feet per minute (BFPM), while bandsaws that cut metal are designed to normally run between 75 and 350 BFPM. If using a wood cutting machine to cut metal, it is recommended to use blades made of bi-metal Diemaster 2 stock for longer life of the blade, as carbon steel blades (NT & FB) will have a very short life. If your intent is to do a lot of metal cutting or the major use of the saw is for cutting metal, it is recommended that a metal cutting saw be used.
When Selecting TPI Remember:and you want to cut metal, it is suggested you use bi-metal Diemaster 2 blades for longer blade life.
More TPI gives a smoother but slower cut. Fewer TPI allows for a faster cut with a slightly rougher cut surface. Should have at least 3 teeth and less than 12 teeth in the work piece.