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Thread: Prevent Bandsaw Blade Break

  1. #1

    Prevent Bandsaw Blade Break

    I've been resawing for the first time - some Ash logs from trees that died a couple years ago. Using a 19" 3hp bandsaw and a 1" 3tpi blade. Things were going very well, until the blade broke. I had cut only about 250' of logs. The bandsaw never gave any signs of stress. Are there some steps I should take to prevent another break? I kept the tension fairly high, but not ridiculous; the same as I use for smaller-width blades. I was also running at about 3500 RPM. Should I use a lower tension and/or a lower speed (1750rpm)?
    Thanks for any advice.

  2. #2
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    I get 17,409 feet per minute which is at least 3 or 4 times too fast.
    My math must be wrong because the wheel s would fly apart at that speed.
    It is about 185 MPH.
    Bill D
    Last edited by Bill Dufour; 10-13-2019 at 10:53 PM.

  3. #3
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    I buy my blades mail order from these people. I keep spares on hand.

    https://www.google.com/search?q=bc+s...w=1523&bih=726

  4. #4
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    Quote Originally Posted by Bill Dufour View Post
    I get 17,409 feet per minute which is at least 3 or 4 times too fast.
    My math must be wrong because the wheel s would fly apart at that speed.
    It is about 185 MPH.
    Bill D
    I think that he meant fpm, not rpm.

  5. #5
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    Quote Originally Posted by David Buchhauser View Post
    I think that he meant fpm, not rpm.
    But those look close to common rpm's for electric motors so we will see what he says.

  6. #6
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    Quote Originally Posted by Bill Dufour View Post
    I get 17,409 feet per minute which is at least 3 or 4 times too fast.
    My math must be wrong because the wheel s would fly apart at that speed.
    It is about 185 MPH.
    Bill D
    Perhaps he has a 2 speed motor. In any case, his blade speeds are probably around 3000 to 3600 FPM on high and half of that on low speed.
    David

  7. #7
    Quote Originally Posted by Paul F Spiegel View Post
    I've been resawing for the first time - some Ash logs from trees that died a couple years ago. Using a 19" 3hp bandsaw and a 1" 3tpi blade. Things were going very well, until the blade broke. I had cut only about 250' of logs. The bandsaw never gave any signs of stress. Are there some steps I should take to prevent another break? I kept the tension fairly high, but not ridiculous; the same as I use for smaller-width blades. I was also running at about 3500 RPM. Should I use a lower tension and/or a lower speed (1750rpm)?
    Thanks for any advice.
    Bandsaw blades are like anything else, you can get some good ones and some bad ones. The bandsaw blade material is made on a continuous roll and when made they pull out the length they need, cut it and weld it together. If the blades are not welded properly they will break. I've had blades break right when turning the saw on before cutting anything. If you purchase blades from a saw sharpening shop they usually will warranty the weld and if you break one will re-weld it for free.

  8. #8
    Thanks for the feedback so far. Sorry for the confusion over my speed numbers. Should have double-checked first instead of relying on (a very faulty) memory. My bandsaw is a two-speed: 3500 fpm and 1700 fpm. I have always run it at 3500 fpm. I don't know how to convey blade tension though. On the scale provided on the machine, I tension the blade to about 80% of the indicator's max value (FWIW).

    Thanks again,

  9. #9
    Quote Originally Posted by Edward Dyas View Post
    Bandsaw blades are like anything else, you can get some good ones and some bad ones...
    This ^^^ Bandsaw blades are pretty much a consumable. I would buy several more. If you break another one, then let's start talking about technique, proper blade selection, and feed rate.

    Erik
    Ex-SCM and Felder rep

  10. #10
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    Is your wood still wet inside? If so, you need a blade designed for that purpose, like the Lennox Woodmaster GT which has enough set to clear out the wet sawdust. Also, a 3 tpi blade would not be a good choice in anything very thick, say more than 4 to 6", whether green or dry. I use a 7/8 pitch blade on my bandsaw lumber mill.

    Take a look at this link for how to make a blade tension meter: https://sawmillcreek.org/showthread....-tension-gauge There's no reason to guess about tension.

    John

  11. #11
    Thanks to everyone for the suggestions and info. I especially liked the link to a tension jig.

    Paul

  12. #12
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    Quote Originally Posted by Bill Dufour View Post
    But those look close to common rpm's for electric motors so we will see what he says.
    Unless it’s direct drive he’s going to be slowing it down considerably with the belt drive pulley ratio.
    Bumbling forward into the unknown.

  13. #13
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    If you are sawing logs on a stationary saw (and moving the logs thru it) that's likely your problem. A log can shift and jam up the blade. The right type of saw will move over a stationary log. Much bigger saws may have tracks to move the logs but I doubt you have one of those.

  14. #14
    Join Date
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    I lay an abrasive on the table and round the back of new blades. Not round so much as soften.

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