Broken handle - any ideas?

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  • Broken handle - any ideas?

    Hello Friends,

    I broke the handle of my friend's miter saw . Unfortunately the replacement part is no longer available. He says it is OK as the saw has been 20 years old but I feel very bad and want to fix it the best way I can.

    I tried gluing it together with epoxy but I don't think it is going to hold.

    There are two actions this handle performs -

    1. turning it to tighten the handle holds the position of the miter saw to desired miter angle. So this action experiences twisting torque.
    2. handle is loosened and used to shift the saw to desired miter angle. This action involves sideway bending moment.

    My plan is to make a handle using large wooden dowel rod.

    Question is should I

    (option A): just drill a blind hole, insert the screw and epoxy it in place?

    (option B): Or should I cut the dowel in two pieces, insert the machine screw with a through hole and then glue back the dowel pieces? When gluing the two dowel pieces of the handle, I am thinking of inserting a couple of small 1/4" dowel pins to help withstand the forces on the glued joint.

    I am leaning towards option B - What do you guys think?

    Thanks in advance.

    NG
    Click image for larger version

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    Attached Files

  • #2
    Dowel is ok, just make one from oak or walnut that is a hard wood, not soft like store bought dowels. If you split the dowel, tape it back together and drill it the correct size you can use a bolt with a hex head. Chisel out for the head and pins shouldn’t be necessary after you epoxy it back together.

    Comment


    • #3
      Originally posted by capncarl View Post
      If you split the dowel, tape it back together and drill it the correct size you can use a bolt with a hex head. Chisel out for the head and pins shouldn’t be necessary after you epoxy it back together.
      Are you suggesting the dowel split lengthwise??

      For splitting the dowel I am thinking of cross-cutting the dowel, using one piece to put the bolt through and reconnecting the cross-cut sections back to rebuild the dowel rod. That way I get the bold embedded inside the dowel handle.

      The small dowel pins I mentioned will bear the twisting and shearing forces experienced by the glued cross-cut that I rejoined.

      Thanks .....

      Comment


      • capncarl
        capncarl commented
        Editing a comment
        Yes split the entire handle lengthwise. Butting 2 cut ends together will not last long, glue just don’t hold a butt joint well. Pins only add to the misery. I see in the next few posts suggestions for hanger bolts. That’ll work too!

    • #4
      See post no. 11 and 12 in this thread https://www.sawdustzone.org/forum/di...bt3x-using-smt where I made a handle like that using a hanger bolt.

      Click image for larger version  Name:	image_28043.jpg Views:	4 Size:	83.4 KB ID:	850438

      To screw the hanger bolt into the dowel lock two nuts onto the bolt threaded part and use some wrenches.
      You can choose the size of the dowel and the length and thread sizes of the hanger bolts available at most hardware stores. I bought two overnight from Amazon for 2 bucks, I think. You can thread the bolt into the dowel or cut it with a hacksaw if too long.
      Trust me the screw thread in the dowel will be much tighter than the bolt thread in the miter saw there is no danger of unscrewing the wrong end when the miter saw is locked to normal torque to hold it.
      Attached Files
      Last edited by LCHIEN; 05-02-2022, 05:58 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


      • #5
        Hi Loring,

        This is definitely interesting. I need to check if I will get the correct threads on that hanger bolt. The saw is Hitachi (Before it became Metabo) so I am afraid the threads are metric. So I always focused on reusing the original bolt. But let me find that.

        Thanks for this idea.

        Comment


        • #6
          Originally posted by nicer20 View Post
          Hi Loring,

          This is definitely interesting. I need to check if I will get the correct threads on that hanger bolt. The saw is Hitachi (Before it became Metabo) so I am afraid the threads are metric. So I always focused on reusing the original bolt. But let me find that.

          Thanks for this idea.
          I have a spare original handle for my Hitachi (now Metabo HPT) C12FDH miter saw, You are welcome to have. I'll check the threads. Probably metric

          Looks like 10 mm (~9.8) on threads outside dia. and the overall handle length is 9.25"

          But frankly, probably easier to make one like I suggested with the dowel than for me to ship this one.
          Last edited by LCHIEN; 05-02-2022, 07:03 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


          • nicer20
            nicer20 commented
            Editing a comment
            Yeah of course, let me check on Amazon. If I find the right one definitely that is an easier option. Thanks for the offer in any case. I will keep that as a last resort. Can't thank you enough.

        • #7
          Lots of 10 mm (M10) hanger bolts of various lengths usually half screw and half M10 threaded on Amazon
          But not the local hardware stores.
          DO a search for M10 x 100 mm hanger bolt which is about 4" long 2" wood thread and 2" M10 threaded. saw 50, 70 ad 100 mm lengths.
          Last edited by LCHIEN; 05-02-2022, 07:41 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


          • capncarl
            capncarl commented
            Editing a comment
            Caution with ordering hanger bolts. I checked on Amazon and they had quite a selection but were not obviously specific with the thread pitch. I’m not sure which pitch the Hitachi uses. I’ll check mine tomorrow if I can find my metric pitch gauge. I know of 3 m10thread pitches, ( m10x0.75 m10x1.5, and m10x1.25 ), but my machinist guide also shows a 4th, a m10x1.

          • nicer20
            nicer20 commented
            Editing a comment
            Thanks Loring and Capncarl. Please check the Hitachi pitch - I don't have a pitch gauge.

        • #8
          hitachi handle photos

          click to view

          I don't have a metric thread gauge.
          This shows roughly 6.5 threads per 10 mm which is 1.53 mm so It is 1.5 mm standard pitch obviously Which is think is the most common.



          Click image for larger version  Name:	P5031004 (2).jpg Views:	0 Size:	147.5 KB ID:	850463

          It is very close to 3/8"-16 thread but doesn't fit the thread gauge exactly; it's off if engaging more than 4 threads or so. (10 mm is .394 vs .375") and 16 tpi pitch is 1.5875 mm

          But I found a 3/8"-16 nut and its definitely not fitting more than 4 threads before it binds. So its not SAE.

          I'm convinced its M10-1.5 if it is metric.
          I found this:
          What is M10 standard pitch?
          For example, an M10x1. 5 (coarse) thread has a 1.5mm pitch, while an M10x1. 25 (fine) thread has a 1.25mm pitch.
          Inch & Metric Thread Sizes Explained | Carr Lane Mfg
          so if its quoted as M10 with no pitch spec most likely its 1.5 mm pitch for the hanger bolts. Coarse pitch is used most often. in both metric and SAE.


          And the threaded length is 20 threads or 3 cm or about 1.25"

          In this listing for 50, 60 and 70 mm long bolts the seller confirms 1.5 mm pitch in the questions https://www.amazon.com/Hanger-M10x50...38&sr=8-6&th=1

          Back to the Hitachi, recalling my saw came with a bolt (no handle) securing the miter table in shipping w/o the handle sticking out and the handle packed separately.
          Attached Files
          Last edited by LCHIEN; 05-03-2022, 03:59 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


          • #9
            Thank you Loring for showing this method

            Yes mine also shows ~6.5 threads in 10mm. I will look into getting a suitable hanger bolt now. Thanks so much for all this help. You are so nice.
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            Comment


            • #10
              As another option if you can't find a hanger bolt.
              Hacksaw off the head of a 10 mm bolt. One with an unthreaded shank area.
              Drill a 10 mm hole 1" deep into the end of a 1-1/4" dowel.
              1/2" from the cut off end of the bolt shank, drill a cross hole - a V-block from one of my DIY jigs will help this tremendously.
              A no. 35 or 36 drill 0.110" for a 6-32 threaded hole is probably good. Then tap the hole with a #6-32 thread.
              If you don't have a tap and drill set they are handy for small shop items. no 6,8,10, and 1/4" drill and tap set would probably be ideal.

              Drill a matching hole in the side of the dowel through the 10 mm hole (again the V-block to center it) a clearance diameter for no. 6 machine screw which is no. 27 or .138" dia. from one side not quite through. Countersink the entrance side for a screw head (flat would be real good but any is OK).
              Now you can run a screw of the right length through the side and into the shank of the bolt to secure it.
              One piece dowel that won't work loose.

              https://www.amazon.com/Bosch-BDT11S-...s%2C490&sr=8-9
              I use a tap and drill set for threading wood and metal... works OK on wood if you don't use it hard for fine adjusters and stuff.

              If you don't have or want a tap and drill set a 1/8" hole in the shank and a 1/8" roll pin 1" long will probably do the job.
              Roll pins are spring steel, have a bevel end and can be driven into the hole size tightly and not fall out. Easily available at hardware stores.

              Or even without a side fastener, simply gluing the shank of the cut off 10 mm bolt into a 10 mm hole will be better than your original idea of an oversize hole to accommodate the hex head of the bolt and filling with epoxy.
              Last edited by LCHIEN; 05-03-2022, 03:28 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


              • nicer20
                nicer20 commented
                Editing a comment
                Great - I think all of the above ideas are definitely better than my Option A & B in the original post. Thanks so much.

            • #11
              I checked the handle on my Hitachi. My thread gauge say is it is a m10.5, I also checked it with another thread checker to verify it.

              The stud length is 54,5mm long, with the threaded length 33 mm. The threads could be longer if necessary.

              Comment


              • LCHIEN
                LCHIEN commented
                Editing a comment
                M10.5? I didn't think sizes that large came in half mm steps.

                You sure you don't mean M10x1.5?

            • #12
              Originally posted by capncarl View Post
              I checked the handle on my Hitachi. My thread gauge say is it is a m10.5, I also checked it with another thread checker to verify it.

              The stud length is 54,5mm long, with the threaded length 33 mm. The threads could be longer if necessary.
              Do you mean m10 x 1.5 as Loring and I have measured above?

              Thanks

              Comment


              • #13
                Yet another solution is a M10 all thread rod, cut to length and then embed a couple of inches into the dowel.
                It can be secured in a snug fit hole with a glue and a hammer, or by threading the dowel for M10 and threading it in with glue. Or with a clearance hole and roll pin.

                M10 all thread is about 7 or 8 bucks at Amazon.
                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


                • nicer20
                  nicer20 commented
                  Editing a comment
                  Oh that's superb. I think I will go this route. No strength issue this way !!
                  Thanks a lot .....

              • #14
                All this handle does is snug up the rotating power head piviot. It doesn’t have to be tightened squeaking tight. I think that if you thread it through the wood dowel with a generous coating of epoxy and put a jam nut on each end it will hold to the end of time.

                Comment


                • nicer20
                  nicer20 commented
                  Editing a comment
                  Oh ok - thanks !

                • LCHIEN
                  LCHIEN commented
                  Editing a comment
                  Doubt a jam nut is even needed. Except perhaps to thread it into the dowel initially.

                • LCHIEN
                  LCHIEN commented
                  Editing a comment
                  Doubt a jam nut is even needed. Except perhaps to thread it into the dowel initially.

              • #15
                nicer20 Post a picture when you make it!
                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


                • nicer20
                  nicer20 commented
                  Editing a comment
                  Yes of course !
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