Band saw blades are available in a wide variety of materials, widths, tooth design and configurations.
How band saw blade width is determined
Band saw blade width is measured the tips of the blade teeth to the edge of the blade at the rear. When selecting blade width of a band saw, the relevant instructions for the machine in question should be followed.
How to choose the correct band saw blade width
The word ‘width’ in this context refers to: the maximum capacity of 
a particular band saw; and the minimum radius a woodworker would want to cut.
For example, if you’re resawing or doing cut-off sawing or cant, the maximum blade width of your machine should be used. This will ensure you get really nice, straight and neat cuts and you’ll also get a good feed rate without any blades breaking.
At the other end of the spectrum, if you’re into contour sawing, use a blade that’s narrow enough to cut the required radius. These blades can cut a much smaller radius than their wide counterparts when they are cutting a curve. For instance, if you use a 3/4-inch- wide blade, it can cut a 5-1/2-inch radius (as shown in the table below), just as a 1/8-inch blade can cut a 3/16-inch radius. Here’s a chart that will show you the correlation between blade width of a band saw blade and the minimum radius it can cut:
| Blade Width | Minimum Radius |
|---|---|
| 1/8″ | 3/16″ |
| 3/16″ | 5/16" |
| 1/4″ | 5/8" |
| 3/8" | 1-1/2" |
| 1/2" | 2-1/2" |
| 5/8" | 4" |
| 3/4" | 5-1/2" |
| 1" | 7" |
Source: Choosing And Using Bandsaw Blades, https://www.kmstools.com/blog/choosing-bandsaw-blades
Band saw blade width can also be chosen according to the number of teeth per inch (TPI). Through this, the desired finish and the correct feed rate can be obtained. A coarse tooth blade of about 2 or 3 TPI can be used to re-saw wood and cut thicker stock to a maximum of eight inches. For cutting thinner metals and plastics below a quarter inch in thickness, one can use a fine-toothed blade, ranging from 18 to 32 TPI. If you cut wood of about 3/4″ thickness, use a 4TPI blade for a fast cut and 14 TPI for a slow cut but an infinitely smoother finish.
While choosing a blade for your band saw, remember that the wider blades are stiffer and work well for cutting metal. They also track better on band wheels than on narrow blades. If thicker material must be cut, a wider blade is less able to deviate because when the back end is in the cut, it steers the front part of the blade.
When you re-saw a piece of wood, the narrower your blade, the straighter the cut it will give you than a wider blade would. With the force of cutting, the blade will swerve to the side, while a narrow blade will push it backwards rather than sideways.
Tips to select the right TPI
- The higher the TPI, the slower the cut but the smoother the finish
- Low TPI is inversely proportional to a fast cut with a slightly rough finish
- There must be a minimum of three teeth in the piece worked on.
