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Bamboo Pin Joint Reinforcement

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  • Bamboo Pin Joint Reinforcement

    I use this process to reinforce wood joints. I started using this method about ten years ago to bolster all sorts of wood joins. It is a bit time consuming and requires a few hand tools, but the method can substitute for more complex joinery. That may sound a bit heretical for classic woodworking, but the same was said when biscuit joinery and pocket screw joinery came into being. I position the pins where they won't be seen once the piece is completed. The pins are placed to prevent the join from moving in any unsupported direction, like the side of a dovetail joint. By placing the pins on opposite sides of the join and angling them at a small angle, they will not allow the joint to move to open the joint. I think it works because of the better aliphatic resin glues we have these days. A lot of wood joinery was developed years ago because wood glues didn't have the long life and humidity resistance of today's glues. Bamboo makes a good strong choice for the pins (wooden nails) because of its long straight grain. I use wooden skewers found at the grocery store. They are usually 1/8" in diameter, but lately I've found some that were 5/32". The skewers can vary slightly in diameter, so I draw them through a steel drill size plate to ensure the diameter is matched to the drill bit being used to drill the pilot holes. The pin is given a bit of glue and tapped into the hole with a mallet. Once seated, I cut the pin off with a pair of side cutters. The wet glue swells the pin and surrounding wood to make things tight. When the glue has cured, I pare the stub off flush with the surface with a chisel. Then the surface can be sanded smooth for finishing. Since the end grain of the pin is exposed, it will darken more than the surrounding wood when finished, which is why I place the pins where they won't be seen in the finished piece.
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    Last edited by Jim Frye; 02-10-2021, 11:14 PM.
    Jim Frye
    The Nut in the Cellar.
    ”Sawdust Is Man Glitter”

  • #2
    Interesting method. Great use of a not normal material. Are the pins slightly smaller to allow for a glue gap?
    just another brick in the wall...

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    • #3
      Most times the skewers are a tad smaller than the hole the numerical equivalent drill bit creates. That's why I use the steel drill bit plate to ensure the pins are not too large. Since the skewers are about a penny apiece, it's not an issue to reject one that's too large.
      Jim Frye
      The Nut in the Cellar.
      ”Sawdust Is Man Glitter”

      Comment


      • #4
        Thanks for following up on the request to explain this technique. I like this method a lot. Strongly agree with glue effectiveness comments. You have the makings of a good magazine article here.

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        • #5
          I have used them (bamboo skewers) also - when I was in Japan. They work great.

          I have made a few projects with the Kreg Pocket Hole Jig and, like you place the holes where they cannot be seen except from the back, bottom or very top of a tall object. It is not hard to place connection points for dowels or screws (in most cases) so that are totally hidden. It is just a process of thinking it through and sometimes making a minor alteration to the design - if it does not distract from the aesthetics.

          Where did you get your drill/dowell sizing plate? I was needing one a few months ago and discovered that a good sizing jig for dowels was expensive. $50 - $60. For a one time project and a two or three years between use, I didn't need one that bad. BUT, I am finding dowels are not equal in sizes in the same batches - because they expand and contract in different directions with humidity swings.

          I found them; I was looking for dowel maker/sizing jigs that are 1/4" thick (somewhat expensive); I found several 1/8" thick steel drill bit size checkers. I will order me one.I rarely need more than a foot of dowel for a specific use - therefore the 1/8" steel should do fine.
          Last edited by leehljp; 02-11-2021, 10:04 AM.
          Hank Lee

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

          Comment


          • LCHIEN
            LCHIEN commented
            Editing a comment
            Looks like he used one of those drill size gauges... the metal kind, not plastic.

        • #6
          Looks like a voodoo project :-)
          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


          • #7
            Originally posted by LCHIEN View Post
            Looks like a voodoo project :-)
            or an porcupine in development.

            It is interesting on the concept of non-90 locks. Toe-nailed nails and screws do the same, if it is thought out. . . In construction framing, toe-nailing is a given, but there is more to it than meets the eye for inexperienced helpers. I grew up around it and it doesn't take any "thinking" on my part, just simple "do it". But in helping build a church recently, good intentioned volunteer helpers had no clue about toe-nailing when building walls - 2x4s joined in "T" formats. As long as the hammer was aimed at the board, it was OK in their mind and the result of letting them do from observation, nails in all directions but the joining.

            I have watched as walls were built 1. in place, and walls built 2. on the floor - and raised in place. Built in place required toe nailing; built on the floor and raised in place usually had 2 nails at 90 to the top and bottom boards (beams?) and straight into the studs. So, my point is, I have watched the removal of a stud for a change in plan after the walls are constructed. The "straight in" nailed studs are usually easer to remove than the angle nailed (toe-nailed) studs. There is a bit of a caveat: angle nailed (toe-nailed) studs usually have 3 nails, Straight in nails usually have two nails. And the toe-nailed studs are more resistant to movements from several directions. Hence - Jim's all direction pins - (stronger).
            Last edited by leehljp; 02-12-2021, 10:42 AM.
            Hank Lee

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

            Comment


            • #8
              Jim, thanks for the timely tip!

              I have been having a problem with the rungs on my Oak dining room chairs coming loose. I tried to reglue them with Gorilla Clear Wood Glue but they still don't hold. I was thinking about pinning them with 1/8" Oak dowels. I'll go to Bamboo instead since it should be stronger.

              Lee, where did you find your drill size plate?
              Don, aka Pappy,

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

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              • #9
                Pappy, try this:

                https://www.amazon.com/Irwin-12092-2...3237881&sr=8-2

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                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


                • #10
                  Dowell plate:
                  Since I only need 7 sizes, 1/8, 3/16, 6mm, 1/4, 5/16, 3/8 and 1/2, I have been contemplating getting me a 6" x 12" plate of 1/8" thick steel and making my own dowel plate. I have the 115 bit set in cobalt, and using the drill press for perfect sizing, it should work.
                  Hank Lee

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

                  Comment


                  • #11
                    I save chop sticks for that reason. Click image for larger version

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                    • #12
                      Bamboo?

                      My everyday chopsticks are square, and often with beveled edges. Throw-away kind! Not bamboo.
                      Last edited by leehljp; 02-14-2021, 11:04 PM.
                      Hank Lee

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

                      Comment


                      • #13
                        Lots of bamboo chopsticks from takeaway orders., haha.
                        We always use our own and have been accumulating the disposables.
                        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

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