Shop made bandsaw tension meter.

[WellsWood]

Or you could just pluck it 'til it sounds right...
S

Hopefully, soon I'll be able to do just that, the point of the exercise for me has been largely to find out what "right" sounds like. On my old EB with no spring I could tweak it while running until the flutter disappeared and it just sounded sweet, a little trim of the tracking to allow for the altered tension, and away you go. It gave lots of feedback for fairly minor adjustments. This new beast isn't like that (yet anyway), it's much much stronger in the frame and, combined with that big spring in the tensioning system, doesn't give much in the way of clues to what's really going on. Fairly substantial changes in tension don't appear to have much affect on anything to my as yet untrained ear - hence the need for a known quantity as a starting point.

 

[ivan]

Glad this proved useful! I relied on the FWW article, as they checked their home made "extensiometer" against a proprietory bandsaw tension gauge.

Blade "Tension" isn't, really, as it is measured in psi. True tension in the blade is measured in lbs, kilos, etc. What is colloquially called blade tension is the pull in the blade divided by its cross sectional area. The spring has to push at twice this load. A narrower or thinner blade which compresses the spring the same as its bigger brother, will have a higher (psi) "blade tension". Also the X sectional area of different (say) 3tpi 1/2" blades will depend on the size of the gullets.

Fortunately confusion between materials science, blade designers, and woodworkers is overcome by the practical assumptions made by Starrett or Lennox etc. who made the gauge FWW used as their standard.

My original post suggested measuring over 150mm when an extension of 0.01mm corresponds to 2000 psi - if you found any misplaced decimal points let me know and I'll edit them out.

 

[hpl]

I'd been looking for an easy way to get an idea of the tension on my blade. The only article I'd seen didn't suggest the vernier gauge idea. I'm going to try it tomorrow!! Thanks guys.

 

[ivan]

~The cheapie Lidl digital caliper doesn't realy need modifying, you can see how your saw reacts to higher tensions (how much does the top guide move?) and get used to the feel. I generally check what the built in gauge says, for tensioning the next time. Recheck if you get a new blade as the buit in gauge is affected by blade length.

My Ax 5300 will tension a 1" bimetal blade to ~25,000psi the reccomended tension for resawing with bimetal.