Kerf closed - what to do? & ripping question

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  • MilDoc

    #1

    Kerf closed - what to do? & ripping question

    While ripping a bunch of Texas Red Cedar, one board became impossible to push. The kerf had closed, despite the Shark riving knife. Luckily, this happend half-way thru, so i turned the board over and finished the cut. The kerf closed again, but I was able to finish.

    I know this is due to stresses in that particular piece of wood, but is there a better way to finish the cut? What if this happened early on?

    And, on the subject of ripping. the boards were 4" wide and had to be ripped exactly in half. I did this by using a scrap 4" piece and making several trial cuts until the pieces were equal. Is there a better way?
  • Jim Boyd
    Veteran Member
    • Dec 2002
    • 1766
    • Montgomery, Texas, USA.
    • Delta Unisaw

    #2
    Put a wide wedge in the kerf. For getting exactly in the middle, that is what I would do.
    Jim in Texas and Sicko Ryobi Cult Member ©

    Comment

    • WEG
      Established Member
      • Nov 2003
      • 298
      • Nahant, MA.

      #3
      Hi Paul;

      Hey, nice pic of the "little one". My guess is a new grandchild??
      As for Texas Red Cedar, we don't grow much of that up here, but the "centering" thing maybe I can give some advice (not good, but some...).
      First measure to the middle of the board, then make a small cut. No need to rip the entire board sample. Then turn the board over and see where it lines up with the saw blade. 1/2 the distance between these two is the place you want to put the center of your blade. This should give you pretty good "same size" pieces. Now if they have to be "exact" but not "exactly" 1/2 the original, then do the same as above, then rip the somewhat larger one the same size as the smaller. I would think you will be taking off only a sliver of wood with this second cut. Make sense?? Hope this helps out. I'm sure there will be some others giving better advice, so just wait...
      WEG
      Happy Holidays!

      Comment

      • LCHIEN
        Super Moderator
        • Dec 2002
        • 21992
        • Katy, TX, USA.
        • BT3000 vintage 1999

        #4
        If being perfectly split is more important than the final width, why not rip it close to the center and then rip them again to the same width? That's what I do when I want two halves of a board to be the same width. If you are any good, the original rip will be better than 1/16th inch so the final rip will not lose more than 1/32" of what you would have had had you split it exactly, and it's much easier this way. (hmmm, I think I said pretty much the exact same thing as WEG).

        The cedar I get for fence boards is never the same width, anyway (or the same thickness for that matter, even from one side of the board to the other).
        Last edited by LCHIEN; 04-16-2006, 01:07 AM.
        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

        • drumpriest
          Veteran Member
          • Feb 2004
          • 3338
          • Pittsburgh, Pa, USA.
          • Powermatic PM 2000

          #5
          I was going to type what Jim already typed, so I won't type that. lol
          Keith Z. Leonard
          Go Steelers!

          Comment

          • MilDoc

            #6
            Great advice, Thanks. BTW, yep, new grandson now 4 months and active as ....

            Loring -- found the same with East Tx red cedar. None exactly the same width, thickness varied from one end to the other. TG for jointers and planers! Nice wood to work, 'tho. Shop hasn't smelled that nice in a long time!

            Comment

            • Rayclav
              Forum Newbie
              • Nov 2005
              • 27
              • BC, Canada.
              • Craftsman 10 inch

              #7
              When ripping and the kerf becomes a problem, stop the machine and put a small wooden wedge in the kerf, pull back on the wood a couple of inches and begin sawing again.

              R

              Comment

              • Stytooner
                Roll Tide RIP Lee
                • Dec 2002
                • 4301
                • Robertsdale, AL, USA.
                • BT3100

                #8
                I generally just pull the stock back out and cut from the opposite side. You can't do that with pawls in place though. Not without shutting down.
                You may not realize it, but the riving knife just saved you from a possible kickback. If it had not been there, the kerf would likely have closed on the rear teeth of the blade instead. That could invade your personal space quickly.
                Lee

                Comment

                • Wood_workur
                  Veteran Member
                  • Aug 2005
                  • 1914
                  • Ohio
                  • Ryobi bt3100-1

                  #9
                  That has happend to me more than once. Fortunatly, I was using the safety implancation with the saw, so the blade had no need to beat my piece of lumber up. I doubt I would happen eary in the cut because of all the wood left to support the cuttoffs, but If it di, It would probably kickback. (but you do stand to the side when rippind, right) Also, the short distance between the front of the blade and the riving knife makes the possibility of the wood binding when it has yet to pass the splitter 1/8, assumeing it does bind.

                  I'm sure Loring will correct whatever errors I made in this post.
                  Alex

                  Comment

                  • jarhead
                    Senior Member
                    • May 2004
                    • 695
                    • Boynton Beach, FL.

                    #10
                    I was just about to post a question exactly on the same subject and happen to see this thread. I was ripping an 8/4 piece of cherry and in the middle the saw came to a complete stop. I quickly turned it off and noticed that the kerf started closing at the beginning of the cut. I must say that Lee's splitter saved my arse. To complete the cut, I flipped the board over and finished the cut. I would like to know why the kerf starts to close on a board this size:

                    Comment

                    • Wood_workur
                      Veteran Member
                      • Aug 2005
                      • 1914
                      • Ohio
                      • Ryobi bt3100-1

                      #11
                      because of stress from when the wood was growing, and then the other wood makes the stregnth multiply.
                      Alex

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