Replies

1. 
   saschafer | Aug 31, 2007 05:20am | #1

   Since John hasn't had a chance to reply...

   The optimal tension (measured in pounds per square inch) doesn't change with the width of the blade. However, the amount of force (measured in pounds) required to achieve a certain level of tension does change, since the cross-sectional area of the blade increases as the blade gets wider. So, as you crank the bandsaw tension adjustment wheel, you're increasing or decreasing the force applied by the adjustment spring, in an attempt to reach a fixed level of tension, independent of blade width.

   John recommends 15,000 psi as the "normal" amount of tension to use. Some blade manufacturers, such as the Timber Wolf people (http://www.suffolkmachinery.com/), and some bandsaw users, too, seem to prefer lower tension. (There's a page at the Timber Wolf site that describes a tension-setting procedure, by the way.)

   If you haven't seen it, John has a video describing the construction and use of a homemade tensionometer for setting the blade tension to 15,000 psi: http://www.taunton.com/finewoodworking/subscription/ToolGuide/ToolGuideArticle.aspx?id=5295.

   In my own experience, you only need to get in the general ballpark. Tension is way down the list of things that need to be just right in order to get a good cut; a sharp blade and properly adjusted guides are far more important.

   -Steve

    

2. 
   JohnWW | Sep 09, 2007 10:57pm | #2

   Dan,

   I'm sorry for not responding sooner but I switched jobs, and moved, and had a persistent illness flare up all in the past few weeks.

   Saschafer has already given you an excellent technical answer that I really can't significantly improve on.

   Since I designed the tension meter a number of years ago I have come to the conclusion that tension is not nearly as important as having a sharp blade of the right kind for the cut being done and that moderate tension, that feels right and doesn't put a strain on the machine, is almost always adequate.

   John W.