Diablo 7 1/4" 24 tooth blade X2 pack

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

    Diablo 7 1/4" 24 tooth blade X2 pack

    Found and ordered this two blade pack of Diablo 7 1/4" 24 tooth rip blades for $12.35. That is $6.18 a blade for 0724A. Looks like a great deal.



    I am thinking of using this most of the time in my BT3100 instead of the 10" one as they will still handle 1 3/4" material and I rarely cut thicker than that anyway. Have seen some claiming there is a less chance of kickback with a smaller blade.

  • Jim Frye
    Veteran Member
    • Dec 2002
    • 1051
    • Maumee, OH, USA.
    • Ryobi BT3000 & BT3100

    #2
    Can't go wrong for $12. You might get lucky. I recall how badly maligned thin kerf blades were many years ago, so I sprang $35 for a Freud 24T thin kerf teflon coated blade. It is such a good blade that I still have and use it. So good, I spent another $35 for an 80T version.
    Jim Frye
    The Nut in the Cellar.
    ”Sawdust Is Man Glitter”

    Comment

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

      #3
      Thanks Jim Frye .

      When watching some YouTube videos for table saw safety, I stumbled upon this line of thinking called "Downsizing the blade" from 10" to 7 1/4 thin kerf blades".

      Why were thin kerf blades maligned many years ago? What were the reasons?

      Although the concept is true for any 7 1/4" blade, most everyone on that train of thoughts is recommending this particular Diablo blade.

      Just wondering if the reasons that were probably valid back then have been eliminated with newer technology/designs.

      Would like to hear and learn from your experience. Thanks in advance.

      - NG

      Comment

      • LCHIEN
        Internet Fact Checker
        • Dec 2002
        • 20914
        • Katy, TX, USA.
        • BT3000 vintage 1999

        #4
        I don't like a small blade on the 10" saw.
        It puts a large gap between the riving knife and the back of the blade... giving more chance for kickback.

        Probably the 10" saw will give smoother cuts as well... more teeth per revolution cutting and at a higher FPS linear speed at the cutting tips.

        That's my take anyway.
        Last edited by LCHIEN; 03-16-2021, 06:20 PM.
        Loring in Katy, TX USA
        If your only tool is a hammer, you tend to treat all problems as if they were nails.
        BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

        Comment

        • Jim Frye
          Veteran Member
          • Dec 2002
          • 1051
          • Maumee, OH, USA.
          • Ryobi BT3000 & BT3100

          #5
          Not sure why 10" thin kerf blades were not thought highly of, but Freud came out with laser cut harmonic stabilization technology that allowed the thin kerf blades to perform like ( or better than) old school 1/8" thick blades. Probably just because it was new, conventional wisdom mentality automatically thought it was bad. Flashback for those here that bought the BT3000. Benchtop saw - No Good. Aluminum tables - Junk. Universal motor - Crap. And on and on. I still prefer a 10" blade on the table saw. Less heat build up and possible warping on heavy use. More teeth to do the cutting.
          Jim Frye
          The Nut in the Cellar.
          ”Sawdust Is Man Glitter”

          Comment

          • cwsmith
            Veteran Member
            • Dec 2005
            • 2737
            • NY Southern Tier, USA.
            • BT3100-1

            #6
            My opinion is that a 10-inch table saw deserves a 10-inch blade! A 10-inch blade is more efficient than a 7-1/4, more teeth and as Loring points out the linear speed at the outer edge of a 10-inch blade is faster than at 7-1/4, given the same RPM. Then of course there's just the efficiency of the design of the table saw. Properly adjusted, the larger blade and riving knife are 'mated', proper spacing and curve of the riving knife.

            It's not that you can't use a 7-1/4 diameter blade, after all, a dado is a smaller diameter too; but I think you loose some efficiency that the 10" blade offers. I would also think that given the same RPM and number of teeth per blade, the larger diameter blade would provide more teeth per inch and increased in linear speed would provide for a smoother cut.

            Regarding thin vs normal kerf blades, I just think the thicker blade is more stable and less likely to flex. My logic tells me that a standard kerf (1/8-inch ?) does pose more resistance and strain on the motor than a thin kerf blade, but how much I don't know. With my RAS which has an induction motor, I have mostly used standard kerf blades. With the BT3000's universal motor, I've only used the thin kerf blades. Basically, I've used blades with the same kerf that came with each saw (full kerf on the RAS and thin kerf on the BT).

            But mind you, I found the thin kerf blades gave me better quality and since 2010 that is what I also use on my RAS. (Note that I do not use the usually recommended negative-tooth angle blade on my RAS. It came with positive-tooth blade and though I understand the recommendation, I've always felt comfortable* following that practice.)

            The only change I have really made over the OEM blade type was with my 10-inch CMS. It came with a 10-inch, thin kerf blade and I found it didn't work all that well with that type of saw, especially when compound cutting molding, etc. A thin kerf blade never gave me an accurate cut. At first I thought it was the saw (Ridgid), poor design or something. I read of other complaints too. Then I decided to stick and old full-kerf blade on it (originally used on my RAS). I found the cut much more accurate. I contribute that problem to possible blade flex as I lower the CMS arm into the cut. On both a table saw and the RAS, the action is a straight path through the stock, while the CMS has more of a downward, angle path with stress placed differently as I see it. In any case, I found the thicker kerf to make a better cut.

            CWS
            Think it Through Before You Do!

            Comment

            • Slik Geek
              Senior Member
              • Dec 2006
              • 669
              • Lake County, Illinois
              • Ryobi BT-3000

              #7
              I love the small blade on the 10" saw! I've been using 7-1/4" Diablos on my BT-3000 almost exclusively for a decade or more. Works great. But you have to change the riving knife to a thinner material because the Diablo 7-1/4" kerf is much thinner than the 10" blades (~ 1/16").

              Here is what I did (to work with my Shark Guard blade guard):

              I picked up some 1/16" thick sheet stainless steel and created a riving knife that is shorter than the stock riving knife and has a matching diameter to "parallel" the Diablo blade. If you want my pattern, I'll trace my riving knife for you - but note that it is set up for a 15 year old shark guard.

              When I mounted the blade, I found that, even with no shims, my riving knife was a smidgen too far from the motor side of the blade tooth (the side against the inner blade washer). That caused interference and friction while sawing.

              To fix this, I put two layers of HVAC metallic tape onto the labeled side of the Diablo blade to shim the blade ever so slightly. For your saw, this may not be necessary. I traced the blade washer on the tape so the shim disappears beneath the washer. I then adhered the tape with no bubbles or ridges onto the labeled side of the blade and smoothed it well. I probably clean the blade to remove any oils from manufacturing to ensure the tape adheres well.

              Note that I put the tape on the labeled side of the blade because the blade label will face inward to have the proper tooth orientation on the saw. (After the first time you will do so this so quickly in subsequent blade replacements that it isn't a hassle at all).

              I usually use a 40 or 60 tooth Diablo and get really smooth cuts. Sometimes the sawn edge almost looks planed.

              From somebody who has used both sized blades on the BT-3000, I think that you'll be glad you tried it. There are advantages with the smaller blade.
              • Less vibration. The teeth are closer to the arbor so the really thin kerf blade is quite stable.
              • Less sawdust. Less wood is removed in each cut so there is less dust produced.
              • Less waste. I recently made a bunch of kitchen cabinets. When I ripped the maple for the face frames that thin kerf allowed me at times to get an extra cut out of wood that I otherwise would have had insufficient width to use for the frame.
              • Reduced load on the motor.
              • Much cheaper. The 7-1/4" blades are so much cheaper.
              • (I haven' compared this carefully, but my cuts are really smooth so I'm doubtful that you are loosing anything with regard to smoothness on the cut)
              I rarely put in a 10" blade on my Ryobi unless I am cutting wood thicker than 1-1/2" or I'm cutting dadoes, and then I am still putting on a "smaller" blade.



              Last edited by Slik Geek; 03-26-2021, 10:26 PM.

              Comment

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

                #8
                Slik Geek Thanks. The advantages you list are very much similar to what I have also learnt from the proponents of smaller blades. So I am going to give the smaller blades a serious try. I had been concerned about the splitter/riving knife issue given that the stock riving knife is thicker.

                I would love to receive your pattern when you get a moment and build a riving knife for the blade. Any suggestions where to obtain the required metal stock - I will check HD/Lowe's if they carry any such sheets. May be they have Aluminum in that size which may be easier to work with.

                I understood the label issue - yes the smaller blades primarily designed for Circular Saws are labeled on the "other" side when compared to the Table saw blades.

                But I am confused with your comment about the "riving knife was a smidgen too close to the motor side of the blade (the side against the inner blade washer)." and corresponding explanation of shimming the blade. I thought in such situation you would be shimming the blade guard to align properly with the blade plane.

                Thanks in advance.

                - NG

                Comment


                • Slik Geek
                  Slik Geek commented
                  Editing a comment
                  Sorry for the late response.  Elderly parent had a health issue that has consumed my life, starting a few hours before you posted. I'll provide more insight on this thread.

                • nicer20
                  nicer20 commented
                  Editing a comment
                  Slik Geek - Oh I hope everything is fine now with your parent. No need to apologize for the delay. This is not at all urgent. Thanks and wishing you & your family a happy healthy season.
              • leehljp
                Just me
                • Dec 2002
                • 8429
                • Tunica, MS
                • BT3000/3100

                #9
                Originally posted by nicer20
                Slik Geek Thanks. The advantages you list are very much similar to what I have also learnt from the proponents of smaller blades. So I am going to give the smaller blades a serious try. I had been concerned about the splitter/riving knife issue given that the stock riving knife is thicker.
                - NG
                I once made a riving knife out of aluminum and rounded over the front edge to the point that it was almost knife edge, - just not sharp. The one mistake I made was that the riving knife was about .01" thicker than the kerf of the blade. I tried cutting something along the size of 2ft x 2 ft of 3/4" plywood. Quality plywood does not give! The blade cut it fine, it (plywood) entered into the riving knife front edge section just fine. But when it got to the full thickness of the riving knife, it STOPPED and would not let me continue feeding it. That plywood did NOT like the riving knife being .01inch thicker than the kerf.

                I did not check at the time, but it could be that the plywood WAS giving (flexing outward .005 or so) and that small amount caused a wedge between the fence and the riving knife in addition to the drag ON the riving knife itself. I took that riving knife OFF!
                Hank Lee

                Experience is what you get when you don't get what you wanted!

                Comment


                • nicer20
                  nicer20 commented
                  Editing a comment
                  Oh wow !! So the tolerances are pretty tight - something to watch for I guess. Thanks for sharing this. Really appreciate it.

                • Slik Geek
                  Slik Geek commented
                  Editing a comment
                  Excellent observation. Very glad that you posted this caution!!!
              • Slik Geek
                Senior Member
                • Dec 2006
                • 669
                • Lake County, Illinois
                • Ryobi BT-3000

                #10
                Originally posted by nicer20
                I would love to receive your pattern when you get a moment and build a riving knife for the blade.
                I will post that shortly.

                Originally posted by nicer20
                Any suggestions where to obtain the required metal stock
                Hopefully you haven't purchased anything yet, my memory was flawed. As leehljp so astutely observed, the riving knife and blade kerf cannot not match, the knife actually needs to be a bit thinner. I measured my "custom" riving knife and it was thinner than my faulty memory recalled. The material I used was 0.048" thick stainless steel that I purchased from McMaster Carr online. I believe that I made my knife from a 6” × 6” sheet of their 304 Stainless Steel (#8983K114). There wasn't anything magical about the alloy choice, I was trying to find something relatively inexpensive and small so I didn't have lots of waste.

                Aluminum this thin is just too soft, particularly if you are supporting a blade guard (like I am, supporting a Shark Guard). I recommend something stiffer, like steel. I used stainless so it won't rust. You could use other steel alloys and paint the riving knife. Just make sure the knife is at least several thousands of an inch thinner than the blade kerf.

                You were rightly confused by my statement regarding shimming. I didn't describe it accurately. The blade was closer to the motor than the riving knife (possibly this issue only will occur on my saw). That's why I shimmed the BLADE, not the riving knife. Sorry about the confusion. I'll edit my post above to eliminate the confusion.

                The pattern will post soon as I remove the riving knife from the saw it and scan it.

                My blade kerf measures 0.062" wide, so the riving knife has 0.007" of clearance on either side (theoretically). Since reality means the knife won't be exactly in the center, the clearance on either side gives you a smooth performing cut, instead of the high friction result leehljp cautioned about.
                Last edited by Slik Geek; 03-26-2021, 10:29 PM.

                Comment

                • Slik Geek
                  Senior Member
                  • Dec 2006
                  • 669
                  • Lake County, Illinois
                  • Ryobi BT-3000

                  #11
                  Here is a scan of my riving knife. I included a ruler so you can confirm the dimensions are correct and the image isn't scaled. It actually isn't as easy as one might think to create this pattern. The existing knife isn't much help, so much changes in the transition from 10" blade to a 7-1/4" blade. The small holes at the top are for mounting my Shark Guard. You likely will have to customize them.
                  Attached Files

                  Comment

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

                    #12
                    Thanks for the updates and clarifications on the post. Really helpful. Thanks for sharing the pattern.

                    NG

                    Comment

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