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Table Saw Motor Tensioner Bracket Repair

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  • Table Saw Motor Tensioner Bracket Repair

    My customer stored his ancient table saw in the end of the garage in front of the car. One day his wife hit the motor of the saw with her car, when she was putting the car in the garage. It bent the zinc die cast bracket and it also bent the cast iron frame of the saw. The bracket is no longer available. In the first picture you can see the bent bracket.

    1. Bent bracket
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    I wanted to keep the base of the mounting feet of the bracket flat, so I built a fixture to support the bracket, while I straightened it. I used some scrap metal to build the fixture. One plate was 1-1/4" thick and the other was 1" thick so I used dual shield flux core wire to weld it, for high deposition rate and good penetration.

    2 . Straightening bracket
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    Below are some close up pictures of the welds on the bracket (because this is after all a welding forum).

    3. 1st and 2nd pass on fillet weld
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    4. Fillet Weld Done
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    5. Outside weld
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    Miller Thunderbolt
    Smith Oxyacetylene Torch
    Miller Dynasty 200DX
    Lincoln SP-250 MIG Welder
    Lincoln LE 31 MP
    Lincoln 210 MP
    Clausing/Colchester 15" Lathe
    16" DuAll Saw
    15" Drill Press
    7" x 9" Swivel Head Horizontal Band Saw
    20 Ton Arbor Press
    Bridgeport

  • #2
    One side of the bracket, which I labeled good, had two 45° offsets. The other side, which I labeled bad, had one 45° offset and one ba$tard angle. My first step was to straighten the bad side with the setup shown below.

    6 . Straightening setup
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    I applied force until I heard a slight tick sound, which was a very small crack in the upper right side of the bracket as shown below.

    7. Crack in upper right corner
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    Below is a close up of the crack in the corner.

    8. Close up of Crack.
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    The bracket was straighter but not entirely straight, so I decided to bend the good side to match the bad side. To accomplish this I put the straightening fixture in my arbor press as shown below.

    9. Bending the good side
    Click image for larger version  Name:	9. Bending the good side .jpg Views:	0 Size:	112.7 KB ID:	605805
    Last edited by Don52; 01-04-2020, 07:52 AM.
    Miller Thunderbolt
    Smith Oxyacetylene Torch
    Miller Dynasty 200DX
    Lincoln SP-250 MIG Welder
    Lincoln LE 31 MP
    Lincoln 210 MP
    Clausing/Colchester 15" Lathe
    16" DuAll Saw
    15" Drill Press
    7" x 9" Swivel Head Horizontal Band Saw
    20 Ton Arbor Press
    Bridgeport

    Comment


    • #3
      Once we installed the bracket we discovered that the cast iron frame of the saw as also bent. We were concerned that we would crack the cast iron if we attempted to straighten it out, so we added a wedge spacer to compensate for the bent surface. We also noticed that the belt was too long and rubbing on the guard so we made the wedge spacer thick enough to lift the belt off the guard. In the picture below you can see the wedge spacer above the die cast zinc bracket.

      10. Wedge added
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      And here is a closeup picture of the wedge.

      11. Wedge closeup
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      Next we installed the motor. In this picture the motor is hanging down and the belt is loose.

      12. Belt loose
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      We installed the belt.

      13. Belt tight
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      Here is the saw all done. We weren't too concerned with the tiny crack because it was on the compression side of bracket.

      14. All done
      Click image for larger version  Name:	14. All done.jpg Views:	0 Size:	65.9 KB ID:	605811
      Last edited by Don52; 01-04-2020, 07:54 AM.
      Miller Thunderbolt
      Smith Oxyacetylene Torch
      Miller Dynasty 200DX
      Lincoln SP-250 MIG Welder
      Lincoln LE 31 MP
      Lincoln 210 MP
      Clausing/Colchester 15" Lathe
      16" DuAll Saw
      15" Drill Press
      7" x 9" Swivel Head Horizontal Band Saw
      20 Ton Arbor Press
      Bridgeport

      Comment


      • #4
        Did you get lucky on the threaded holes, or have to make a couple more?

        Comment


        • #5

          Originally posted by MAC702 View Post
          Did you get lucky on the threaded holes, or have to make a couple more?
          Yes, I was lucky. The threads were fine.

          -Don
          Last edited by Don52; 01-04-2020, 12:44 PM.
          Miller Thunderbolt
          Smith Oxyacetylene Torch
          Miller Dynasty 200DX
          Lincoln SP-250 MIG Welder
          Lincoln LE 31 MP
          Lincoln 210 MP
          Clausing/Colchester 15" Lathe
          16" DuAll Saw
          15" Drill Press
          7" x 9" Swivel Head Horizontal Band Saw
          20 Ton Arbor Press
          Bridgeport

          Comment


          • #6
            Nice job Don, as always. Don't have any experience fiddling with die cast zinc stuff, but I'm wondering if heating the part, while straightening, would prevent, or lessen, any cracking.

            Comment


            • #7
              Nice fix. I loved making fixtures to do something right...Bob
              Bob Wright

              Comment


              • #8
                Originally posted by Metjunkie View Post
                Nice job Don, as always. Don't have any experience fiddling with die cast zinc stuff, but I'm wondering if heating the part, while straightening, would prevent, or lessen, any cracking.
                We did heat the part with a heat gun, so that it was hot to the touch. (about 150° F)

                -Don
                Miller Thunderbolt
                Smith Oxyacetylene Torch
                Miller Dynasty 200DX
                Lincoln SP-250 MIG Welder
                Lincoln LE 31 MP
                Lincoln 210 MP
                Clausing/Colchester 15" Lathe
                16" DuAll Saw
                15" Drill Press
                7" x 9" Swivel Head Horizontal Band Saw
                20 Ton Arbor Press
                Bridgeport

                Comment


                • #9
                  Nice work, that took a while, that was really nice of you to do that, that for the photo's to show how it was done.

                  Comment


                  • #10
                    Good job on this Don52, I reckon its better to strengthen the crack by drilling in the crack and a few spot welds.

                    Comment


                    • #11
                      I like seeing the old equipment repaired and put back to work.

                      Comment


                      • #12
                        See that the motor is mounted very well, so it's shaft is parallel to the blade arbor shaft. If they are not parallel it can pull the pulley along the shaft.

                        Comment


                        • #13
                          Originally posted by RichardParker View Post
                          See that the motor is mounted very well, so it's shaft is parallel to the blade arbor shaft. If they are not parallel it can pull the pulley along the shaft.
                          What is your experience in fixing motor mounts?

                          Your post is cut-and-pasted from the first reply on the following website, without giving credit to its author or the site: https://www.finewoodworking.com/foru...igning-pulleys

                          Comment


                          • #14
                            Mac i sent you a PM...Bob
                            Bob Wright

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