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Blade Brazing

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  • EdwinB
    I have seen two methods for brazing a bandsaw blade. The first is essentially a butt joint, but the joint runs at a diagonal across the flat of the blade.
    Message 1 of 14 , Feb 1, 2012
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      I have seen two methods for brazing a bandsaw blade. The first is essentially a butt joint, but the joint runs at a diagonal across the flat of the blade. This one is ground by grinding with the blade ends stacked one on top of the other, with the teeth on opposite sides.

      The second method is a scarf joint that runs straight across the flat of the blade, and is ground with the blade ends side by side, with the teeth on on the same side of the blade. Has anyone ever seen a jig that would combine the two methods so you would have a scarf joint that ran diagonally across the flat of the blade? I would think this would be incredibly strong, but it would require grinding each end individually, in a different orientation.

      Regards,
      Ed
    • Bill
      Ed, wouldn t method that shorten the blade enough to disallow it s use on the 4x6 again? Best... Bill
      Message 2 of 14 , Feb 1, 2012
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        Ed, wouldn't method that shorten the blade enough to disallow it's use on the 4x6 again?

        Best... Bill


        On 2/1/2012 9:21 AM, EdwinB wrote:
         

        I have seen two methods for brazing a bandsaw blade. The first is essentially a butt joint, but the joint runs at a diagonal across the flat of the blade. This one is ground by grinding with the blade ends stacked one on top of the other, with the teeth on opposite sides.

        The second method is a scarf joint that runs straight across the flat of the blade, and is ground with the blade ends side by side, with the teeth on on the same side of the blade. Has anyone ever seen a jig that would combine the two methods so you would have a scarf joint that ran diagonally across the flat of the blade? I would think this would be incredibly strong, but it would require grinding each end individually, in a different orientation.

        Regards,
        Ed


      • Paul
        First, I have never seen a blade brazed the first method, only ever saw the second method. It really is a scarf joint, too, just that you are scarfing along
        Message 3 of 14 , Feb 1, 2012
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          First, I have never seen a blade brazed the first method, only ever saw the second method. It really is a scarf joint, too, just that you are scarfing along the width, not the thickness.

          My initial conclusion is based on a quick thought experiment with what you describe below and my conclusion is that it will not result in a stronger joint. Why? Because what you are suggesting, assuming I am following what you are saying correctly, is rotating the blade so that you are getting a scarf joint that is angled across the blade. This will not result in any additional surface area getting brazed, which is what adds the strength. You are, instead, taking a simple rectangular shaped scarfing area and making it a rectangular diamond shape. If you want more strength, you need to extend the scarfed area and that can only come from tapering the scarf longer. I.e. instead of a 1:8 taper (for every unit of thickness you taper the blade 8 units in length) if you increased it to 1:12 or 1:20, etc. you will increase the surface area resulting in increased strength.

          At least that is the conclusion I come to with a quick thought experiment. Perhaps this can be checked via Sketchup or a CAD program, but I don't think combining the methods results in a stronger joint, which is likely why it has not been done in a jig, unless you wanted a jig that could do either method, but not a combo.

          Paul

          --- In 4x6bandsaw@yahoogroups.com, "EdwinB" <n5kzw@...> wrote:
          >
          > I have seen two methods for brazing a bandsaw blade. The first is essentially a butt joint, but the joint runs at a diagonal across the flat of the blade. This one is ground by grinding with the blade ends stacked one on top of the other, with the teeth on opposite sides.
          >
          > The second method is a scarf joint that runs straight across the flat of the blade, and is ground with the blade ends side by side, with the teeth on on the same side of the blade. Has anyone ever seen a jig that would combine the two methods so you would have a scarf joint that ran diagonally across the flat of the blade? I would think this would be incredibly strong, but it would require grinding each end individually, in a different orientation.
          >
          > Regards,
          > Ed
          >
        • n5fee
          I have brazed a number of blades pretty successfully. I made a small fixture to hold the blade against my tool grinder to thin the blade thickness to zero
          Message 4 of 14 , Feb 3, 2012
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            I have brazed a number of blades pretty successfully. I made a small fixture to hold the blade against my tool grinder to thin the blade thickness to zero over a length of about 1/4 inch. The mateing blade was likewise thinned to form a lap joint. I have another fixutre that I clamp the two pieces in to that holds the back of the blade straight and keeps the overlapped joint in proper position. I then put some flux in between the overlap area, heat with a torch and apply brass rod. I have also used silver solder. After natural cooling, I grind off excess filler. This has worked pretty well for me. I had it on my website that Cox discontinued last year. I still have the photos somewhere if anyone is interested in seeing them.

            On a related note, I bought a Harbor Freight blade welder several years ago that has frusturated me to no end. I have never been able to make it work properly. I have welded hundredes of blades using similar welders on commercial welders usually attached to the sides of big band saws in industrial settings and they work perfectly. The HF machine welds always break. I have gone so far to take voltage measurements (using oscilloscope and dvtm), force measurements, upset distances, trace out internal electrical circuits etc. and I see no reason the HF machine will not work. I have taken pieces of blade from a single roll and made joints on the HF at home and two other machines where I work. The ones at work are great, the HF welds break. I have annealed them as recommended. I have tried bi-metal, plain metal etc. from about 10 different blade rolls from different manufacturers with no luck.

            Has anybody been successfully using the HF 220V blade welder? Here is what it looks like:
            http://images.harborfreight.com/manuals/3000-3999/3663.pdf

            Dallas


            --- In 4x6bandsaw@yahoogroups.com, "EdwinB" <n5kzw@...> wrote:
            >
            > I have seen two methods for brazing a bandsaw blade. The first is essentially a butt joint, but the joint runs at a diagonal across the flat of the blade. This one is ground by grinding with the blade ends stacked one on top of the other, with the teeth on opposite sides.
            >
            > The second method is a scarf joint that runs straight across the flat of the blade, and is ground with the blade ends side by side, with the teeth on on the same side of the blade. Has anyone ever seen a jig that would combine the two methods so you would have a scarf joint that ran diagonally across the flat of the blade? I would think this would be incredibly strong, but it would require grinding each end individually, in a different orientation.
            >
            > Regards,
            > Ed
            >
          • Daniel
            I thought about this and did a test some time ago. It is problematic since you are going to have to have precision in both dimensions. In any case, the normal
            Message 5 of 14 , Feb 3, 2012
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              I thought about this and did a test some time ago. It is problematic since you are going to have to have precision in both dimensions.

              In any case, the normal scarf joint hasn't failed in my experience, so you might try it and try to get it to fail.

              --- In 4x6bandsaw@yahoogroups.com, "EdwinB" <n5kzw@...> wrote:
              >
              > I have seen two methods for brazing a bandsaw blade. The first is essentially a butt joint, but the joint runs at a diagonal across the flat of the blade. This one is ground by grinding with the blade ends stacked one on top of the other, with the teeth on opposite sides.
              >
              > The second method is a scarf joint that runs straight across the flat of the blade, and is ground with the blade ends side by side, with the teeth on on the same side of the blade. Has anyone ever seen a jig that would combine the two methods so you would have a scarf joint that ran diagonally across the flat of the blade? I would think this would be incredibly strong, but it would require grinding each end individually, in a different orientation.
              >
              > Regards,
              > Ed
              >
            • trz200
              Does anyone have a drawing or photograph of what a scarf joint looks like?
              Message 6 of 14 , Feb 4, 2012
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                Does anyone have a drawing or photograph of what a "scarf joint" looks like?
              • palama@inwind.it
                On Sat, 04 Feb 2012 17:52:15 -0000 ... http://en.wikipedia.org/wiki/Scarf_joint --
                Message 7 of 14 , Feb 4, 2012
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                  On Sat, 04 Feb 2012 17:52:15 -0000
                  "trz200" <ac9459427@...> wrote:

                  >
                  > Does anyone have a drawing or photograph of what a "scarf joint" looks like?
                  >

                  http://en.wikipedia.org/wiki/Scarf_joint
                  --
                  <palama@...>
                • crknox2001
                  John Moran has a great description of an easy-to-make fixture for brazing bandsaw blades and details on how he makes the scarf joint at:
                  Message 8 of 14 , Feb 4, 2012
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                    John Moran has a great description of an easy-to-make fixture for brazing bandsaw blades and details on how he makes the scarf joint at:
                    <http://www.gadgetbuilder.com/BandSaw.html#BandsawBrazer>.

                    Charlie

                    --- In 4x6bandsaw@yahoogroups.com, palama@... wrote:
                    >
                    > On Sat, 04 Feb 2012 17:52:15 -0000
                    > "trz200" <ac9459427@...> wrote:
                    >
                    > >
                    > > Does anyone have a drawing or photograph of what a "scarf joint" looks like?
                    > >
                    >
                    > http://en.wikipedia.org/wiki/Scarf_joint
                    > --
                    > <palama@...>
                    >
                  • Alan
                    ... Basically, look at 2 wood chisels with the tapered ends facing each other so they become one long piece of steel. The tapers are then brazed/soldered
                    Message 9 of 14 , Feb 4, 2012
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                      At 01:52 AM 5/02/2012, you wrote:

                      >Does anyone have a drawing or photograph of what a "scarf joint" looks like?

                      Basically, look at 2 wood chisels with the tapered ends facing
                      each other so they become one long piece of steel. The tapers are
                      then brazed/soldered together.

                      Alan
                    • stan campbell
                      Has anybody tried plumbing solder? It has some silver and antimony in it, some tin also, I think.   STAN Has anybody tried plumbing solder? It has some silver
                      Message 10 of 14 , Feb 5, 2012
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                        Has anybody tried plumbing solder? It has some silver and antimony in it, some tin also, I think.
                         
                        STAN
                      • Malcolm Parker-Lisberg
                        You need hard solder not soft. That is a high temperature melting point above 610 C (1156 F) to get enough tensile strength. Malcolm   I don t suffer from
                        Message 11 of 14 , Feb 5, 2012
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                          You need hard solder not soft. That is a high temperature melting point above 610'C (1156'F) to get enough tensile strength.

                          Malcolm
                           
                          I don't suffer from insanity I enjoy it!

                          From: stan campbell <stan2778@...>
                          To: "4x6bandsaw@yahoogroups.com" <4x6bandsaw@yahoogroups.com>
                          Sent: Sunday, February 5, 2012 4:07 PM
                          Subject: [4x6bandsaw] Re: Blade Brazing

                           
                          Has anybody tried plumbing solder? It has some silver and antimony in it, some tin also, I think.
                           
                          STAN


                        • Stan
                          In search of simple ways to fix our blades, I found this with lots of pictures! ( i like pictures...)
                          Message 12 of 14 , Feb 5, 2012
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                            In search of simple ways to fix our blades,

                            I found this with lots of pictures! ( i like pictures...)

                            http://wiki.vintagemachinery.org/BandsawBladeSoldering.ashx

                            Stan

                            http://www.toolfools.com/forum 
                          • Malcolm Parker-Lisberg
                            Stan A good useful find. Malcolm   I don t suffer from insanity I enjoy it! Mene, mene, tekel, upharsin The writing is on the wall.
                            Message 13 of 14 , Feb 5, 2012
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                              Stan

                              A good useful find.

                              Malcolm
                               
                              I don't suffer from insanity I enjoy it! Mene, mene, tekel, upharsin The writing is on the wall.

                              From: Stan <stan2778@...>
                              To: 4x6bandsaw@yahoogroups.com
                              Sent: Sunday, February 5, 2012 8:53 PM
                              Subject: [4x6bandsaw] Re: Blade Brazing

                               
                              In search of simple ways to fix our blades,

                              I found this with lots of pictures! ( i like pictures...)

                              http://wiki.vintagemachinery.org/BandsawBladeSoldering.ashx

                              Stan

                              http://www.toolfools.com/forum 


                            • Harold Epps
                              Stan, That s fantastic. I d never have thought of using a drill press and wooden wedge to get the correct angles for the scarf joint. Harold
                              Message 14 of 14 , Feb 5, 2012
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                                Stan,
                                That's fantastic. I'd never have thought of using a drill press and wooden wedge to get the correct angles for the scarf joint.
                                Harold

                                --- In 4x6bandsaw@yahoogroups.com, "Stan" <stan2778@...> wrote:
                                >
                                > In search of simple ways to fix our blades,
                                >
                                > I found this with lots of pictures! ( i like pictures...)
                                >
                                > http://wiki.vintagemachinery.org/BandsawBladeSoldering.ashx
                                > <http://wiki.vintagemachinery.org/BandsawBladeSoldering.ashx>
                                >
                                > Stan
                                >
                                > http://www.toolfools.com/forum <http://www.toolfools.com/forum>
                                >
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