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"Tune" your bandsaw

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Dave D

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I have been following the recent posts on the Thien Separator with great interest. Looks like another item on the to do list.
When visiting Phil Theins website:-
http://www.cgallery.com/jpthien/cy.htm
I found a section on an Audible Tension Gauge.

The idea is to use the calculator on the site to find the frequency that a plucked bandsaw blade should sound when set to the desired tension.
Phil includes some midi files of blades sounding at various frequencies for you to match against your blade but I found this very difficult to do.

Then it occurred to me that there must be a tuning app for a smart-phone for tuning musical instruments and indeed there are lots, many of them free.
I downloaded CLEARTUNE because it gives a readout of the frequency of the blade as well as its musical note and was very pleased to get repeatable results.
So for a given blade all it takes is one visit to Phil's web site to find that 15000psi on a Tuff saw sabrecut blade should result in a boing at 54.6 Hz.
Thereafter every time I use that blade I just wind up the tension while plucking the blade until I see 54.6 on the display and I am done.
I have no way of proving how accurate the setting is but for the moment I am trusting Phil's physics. I also think that I have been massively over-tensioning blades in the past.

Now I wonder if I can use the app to get my plane soles to Be Flat
 

RogerS

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But how do you know the tension you require? Chicken and egg, springs to mind.

Also the formula doesn't seem to take into account the type of metal that the blade is made from.
 

Dave D

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Googling for vibrating strings theory reveals that the frequency only depends on length, tension and mass per unit length. So actual material does not come into the equation.

Different steel of course will take different tensions before breaking and will have different recommended operating tensions.

There is lots of advice on the web about what tension to use. Around 15000 to 20000 psi
is a common figure for carbon steel blades and I have seen 30000psi advised for M42 blades.

I am sure that quite a wide range will do but my experiments with plucking blades showed that I was guilty of stressing my bandsaw unnecessarily. It was concern about that which led me to experiment with measuring tension
 

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