Blade tension is a term used to describe how tight a bandsaw blade is on a bandsaw and is expressed in Pounds per Square Inch (PSI). In order to consistently produce straight and uniform cuts, bandsaw blades require tension.
Before installing a bandsaw blade, the first thing to do is to put tension on the wheel to hold it firmly in place. This should be done each time a saw blade is replaced to insure accurate cuts.
Most bandsaws come with a gauge tension meter, which will indicate the amount of tension required based on the width of the blade. This is a convenient tool to have but cannot be considered absolute. Relying on the gauge is fine, but it is also wise to double-check by feeling the blade’s tension.
There are several methods of arriving at the right blade tension.
One would be to use a tension meter, which is more accurate but costly.
Tightening the saw blade and then plucking it like a guitar string is another. By doing this, the blade should produce a clear tone of a specific pitch and not a dull thud.
An air pressure tension system that uses an air cylinder to tighten the blade is another option if available, and with this, the bandsaw operator can set the band tension by using a machine-mounted pressure regulator.
Sideways deflection of the band is another tension test. With the saw turned off, raise the upper guides 6 inches off the table. Using an index finger, push the blade sideways. The blade should deflect no more than a ¼ inch to 3/8 inch. Note: narrow saw blades will deflect more than wide blades.
Manufacturers typically recommend a range of blade tensions for their products. It is always wise to seek their professional guidance if you’re not sure.
