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Band saw blade tension


Paul Norridge
 

Hi George,
I totally agree, I was going to thank John but you beat me to it!
It is so refreshing to read a post from someone (John) who speaks with facts and not just opinions.
Cheers Paul

On 01 November 2021 at 18:06 "George Taylor, IV" <gtaylor@...> wrote:

John,

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Thank you very much – your knowledge is greatly appreciated and valuable to the community.

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George

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From: [email protected] On Behalf Of John Vreede
Sent: Saturday, October 30, 2021 6:56 PM
To: [email protected] Group Moderators <[email protected]>
Subject: Re: [4x6bandsaw] Band saw blade tension

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Hi George

S-type load cells?work in both tension and compression and these ones have a 7/16 UNC threaded hole in top and bottom, which I made pivot pin type connections to.

The blade is just silver soldered to the connectors.

Because I bought the loadcell and the reader as a pair, the loadcell just plugged into the reader.

Totally Chinese instructions that I could not decipher and?no amount of pressing and holding buttons?etc could I make it read in Lb's or Kgs though its supposed to.?

The reader?reads in units of 20g, Reading of 10,000 units = 200kg. A minor pain in the butt but otherwise its been faultless.??

When I calibrated it against the research grade 500kg loadcell on the tensile tester at the engineering school, the thing calibrated perfectly with slope of 1:1 and intercept of zero, so no need to worry about the accuracy of these $20 loadcells.? Even the $5 Airport luggage weigh scales were as accurate.

All loadcells?creep a little if left under load, I found?out too, but if you read it within a minute or two it's stable.

Easiest to get off AliExpress see the attached Word doc with some screenshots of searches - jv

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Hi all
Been thinking and there is a simpler way to tension a 4x6's blade that everyone can do at no cost, all it needs is a cellphone.
I've made 30sec audio files of a properly tensioned10-14TPI?blade being plucked every 2-3sec.? The 1st file is the blade tensioned?to 22500psi stress for bimetal, the other to 17500psi? stress for carbon steel blades.
Load the files?on your cell phone.
Tension up the blade until the sounds match when you pluck the?back run of the blade. I used the flesh of my thumb or finger, not the nail, as the nail makes a sound that is harder to match.
It's?better than using an App or formula to?work out a frequency and matching to a pure MIDI tone - this is the actual sound of a?blade, at known tension, set with a calibrated loadcell.
Its a bit hard on your fingers so a couple of painless alternatives, that can be used to re-tension the blade, are given.??
This method also provides a way for anyone to calibrate the cheap Chinese ZTTO TC-1 spoke tension meter,?without needing to compare it to a Park Tool.?
I've written out the methods and posted them to the Files section too, along with the audio files. The 3 files are in a single folder called 'Blade tensioning methods' so that they'll be together- jv


 

Great stuff John, i too appreciate all your commenting over the years. I've always considered you as one of "the ones you can trust" when you make a comment
--
Kelly aka kjb25
HF 4x6
Utah, USA