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Bandsaw blade tension

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  • Bandsaw blade tension

    Looking for some advice on how tight a bandsaw blade should be. I don't have a gauge to get the right tightness, but I know many people know a trick on getting this done. I have an old Rodgers MFG vertical bandsaw and a Doall C12 bandsaw, both are metal cutting saws and both work perfect. Looking for some advice on how tight the blades should be....gear

  • #2
    I was taught to crank the adjustment wheel as tight as I could get it by hand, without using any sort of tool or cheater,and even then, the blade is probably not as tight as the manual recommends.

    However, some of the import bandsaws have wimpy frames that will, over time, take a set due to blade tension. My high mileage HF4x6 has become this way and will only track with moderate tension. As blade tension increases, the frame bows and tracking shifts until the blade will no longer stay on the wheel. I keep saying I'm gonna reinforce the HF's frame to cure this problem......

    My current practice is to use moderate tension, just enough to snug it up and prevent the blade from wobbling or deflecting noticeably in the cut.

    If your saw has a stout frame, I'd recommend as tight as you can turn the wheel by hand. If your saw is an import, I'd recommend no tighter than necessary for the saw to cut reliably. Just my 2 cents.


    • #3
      Someone told me that there should be about 1/8" to 1/4" sideways flex in the blade.
      That's how I set mine.
      But that could be an ugly rumor.


      • #4
        Because my HV uses a 1/2 inch blade, I like to make the comparison to a hacksaw. I tighten the hacksaw as much as I can, and/or until I get enough tension to control the blade as I hack. Then I use the thumb/two finger method to gauge what that tension is. Two fingers spread apart, behind the blade, then the thumb opposite that. Pinch and feel/see the deflection you get. Adjust the bandsaw to give you about that same feel.

        If you can't get the tension up on the bandsaw by hand, there's something wrong. Lubricate the threads, etc on the adjustor.
        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


        • #5
          Work a #hitload of math and you come to this conclusion: band saw blades need to be stretched about 1/10 of 1%. Heer's an experiment. Find a stretch of blade you can clamp a coupel of round slugs to so you can measure over a short span. Take a reading with the band just tight enough for a reliable measurement and note it. Tension the band taking readings as you go until you get the desired stretch.

          Record this tension, setting in your muscle memory and use it for future settings. The "twang" will stay constant for a given band thickness and vary inversly in frequency with thickness.

          It's only high school physics.


          • #6
            All sawn up

            My 6" x 4" band-saw is a Chinese one - just the usual.

            The manual is in "Chinglish", but after you "interpret" it, it makes sense.

            Mine is tensioned right up by hand until it gives out a higher-pitched note when "plucked". A "thud" is not good enough.

            I tighten and set the roller guides to +0.001/0.000" clearance and until the side of the blade is vertical.

            Next, I adjust the "tilt" on and for the top/front guide wheel.

            Then I take a test cut. If OK I leave it alone. If it needs re-adjustment, I re-do it until its right.

            Mine doesn't get a lot of use and certainly a lot less than some here, but it has given top service.

            I use the slowest speed and "Starrett" blades. That set-up works very well for me.

            I get through very few blades, but if the usage rate was higher I would not be too concerned as band-saw blades, like hack-saw blades, are just another consumable item in the shop.

            If I have any "heavy" stuff to do, I get my steel/metal/welding supplier to do it on his big band-saw or cut-off saw as its usually required there when I buy it. I do all the smaller stuff - ie up to about 3" myself at home in the shop.