7 blade?

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  • Jim0424
    Forum Newbie
    • Feb 2003
    • 34
    • Dallas, Texas, USA.
    • Two BT3Ks.

    7 blade?

    While researching jigs for cutting thin strips on YouTube, there was a video of a guy that used a 7 blade to minimize kerf waste. Makes sense to me. Does anyone see any problems with doing this on our favorite table saw? I'd appreciate any opinions. Thanks, j.
    My ex-: "No one will ever notice that."
    I will.
  • Black walnut
    Administrator
    • Aug 2015
    • 5451
    • BT3K

    #2
    Yes. Make sure the blade is rated for the speed of the saw. Freud thin kerf 10" fine crosscut blade has a kerf of .091" while a Freud thin kerf 7 1/4" fine cut off blade has kerf of .079 for a difference of .012" If this difference in kerf amounts to any material savings is doubtful to me. If my math is correct, and you are cutting 11 strips (ten kerfs) the difference in board used width is .12"!
    just another brick in the wall...

    Boycott McAfee. They placed an unresponsive popup on my pc.

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    • dbhost
      Slow and steady
      • Apr 2008
      • 9229
      • League City, Texas
      • Ryobi BT3100

      #3
      Well Black walnut summed it up pretty well. I wouldn't think the smaller diameter blade would be all that great of an idea. Another item to mention is you would need a splitter to match the kerf of your blade, so in the case of a thin kerf 7,25" blade you will need to have that custom made.
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    • Pappy
      The Full Monte
      • Dec 2002
      • 10453
      • San Marcos, TX, USA.
      • BT3000 (x2)

      #4
      +I keep a Frued TK 303 in my BT almost all the time. The TK 303 is rated for 10,000 rpm and gives excellent, smooth cuts. Obviously, you are giving up depth of cut but I rarely cut anything over 1 1/2" thick. Thicker than that puts more load on the motor than I am personally comfortable with. I have 3 that I have been using for 10 years or more without sharpening, just keeping them clean, and just bought 2 more.

      Freud TK303 Avanti 7-1/4-Inch 40 Tooth ATB Thin Kerf Finishing Saw Blade with 5/8-Inch and Diamond Knockout Arbor - Circular Saw Blades - Amazon.com
      Last edited by Pappy; 02-05-2024, 12:20 PM.
      Don, aka Pappy,

      Wise men talk because they have something to say,
      Fools because they have to say something.
      Plato

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      • nicer20
        Established Member
        • Sep 2007
        • 365
        • Dublin, CA
        • BT3100

        #5
        I have been using 7-1/4" blades (Diablo by Freud) in my saw for a while now. More than saving material I have read it is safer which is why I went that route. I believe I had even posted the note here on forums. Since I rarely cut anything thicker than 1.5" it has never been an issue.

        But definitely, the thinner kerf is an issue with the riving knife. I have removed the riving knife for now which I know is not a great idea. I am in search of right material thickness to make one.

        Comment

        • twistsol
          Veteran Member
          • Dec 2002
          • 2901
          • Cottage Grove, MN, USA.
          • Ridgid R4512, 2x ShopSmith Mark V 520, 1951 Shopsmith 10ER

          #6
          I'm curious, In what way would using a 7 1/4" blade be safer?
          Chr's
          __________
          An ethical man knows the right thing to do.
          A moral man does it.

          Comment

          • nicer20
            Established Member
            • Sep 2007
            • 365
            • Dublin, CA
            • BT3100

            #7
            My understanding is that with a 7.25" blade there are less number of teeth exposed on the back side. Those are the rising teeth behind the apex which are responsible for lifting and throwing the stock in case of a kickback. I think when I am ripping a 3/4" stock with a 24 tooth ripping blade, I hardly have 2-3 teeth (I will double check this when I get to my shop) showing behind the TDC.

            I think this reduces the possibility of pinching and a kickback.

            I may be wrong.

            Comment

            • nicer20
              Established Member
              • Sep 2007
              • 365
              • Dublin, CA
              • BT3100

              #8
              Here is what I meant. I currently have a 60-tooth 7-1/4" blade installed instead of the 24-tooth rip blade. But it should demonstrate my point. Next to the 3/4" stock you can see at the most 6 teeth of the blade behind the TDC that will be rising and driving the stock up and backward. That is only 10% of the blade for a 60-tooth blade. So, as I said earlier, for a rip blade it is barely more than 2 teeth.

              I am no expert but hope this makes some sense.
              Attached Files

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              • dirtmover
                Forum Newbie
                • Dec 2005
                • 19
                • Ottawa, ON, Canada.

                #9
                I use them all the time. Narrower kerf = less waste = less dust and less strain on this already underpowered saw. Smaller diameter also reduces the torque required = less work for the motor. Added bonus, the blades are cheaper so they make great "burner" blades for ripping garbage materials such as mdf, chipboard and laminate flooring etc. The other side of this is you don't have the same depth of cut and can't feed the stock so fast but I don't think you should be in too much of a hurry with this saw anyway.
                Last edited by dirtmover; 02-12-2024, 09:55 AM.

                Comment

                • Slik Geek
                  Senior Member
                  • Dec 2006
                  • 672
                  • Lake County, Illinois
                  • Ryobi BT-3000

                  #10
                  I've used 7-1/4" Diablo blades in my BT-3000 almost exclusively for about 20 years or more. I made a custom riving knife out of stainless steel (if I remember correctly). I rarely need a 10" blade. Blade cost is much lower, less waste adds up when cutting thin strips. When I have used a 40-tooth Diablo blade, there have been occasions where I have a hard time discerning which was the cut side and which was the jointed side of the piece.
                  Definitely create a new riving knife if you do this. The knife design is different due to the smaller blade diameter! I may have posted my riving knife design on this site some years ago...

                  Comment

                  • Jim0424
                    Forum Newbie
                    • Feb 2003
                    • 34
                    • Dallas, Texas, USA.
                    • Two BT3Ks.

                    #11
                    I really appreciate everyone's opinions on this idea. In retrospect, the concept of saving material with a thinner kerf blade results in a negligible economy.

                    As mentioned, my objective was to cut thin strips, and I guess the 'thin strips' sent my down the reduced-kerf rabbit hole.

                    For those interested in my results, I ended up using a vintage Craftsman 7 fine-tooth blade, getting close to 1/32" strips - accurately and repeatable. I didn't go for a purpose-built riving knife because the pieces I'm working with are small and I made sure to stand aside, out of the line of fire.

                    Here is a picture of the results.

                    Thanks. j.
                    My ex-: "No one will ever notice that."
                    I will.

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