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  • Out of square

    I spent a few hours today retrofitting my cross cut sled for the R4511. I built it originally to use with the TS2400. I removed the front fence (closer to me) and jointed two edges on the JP0610. The wooden runners received screws on their sides to minimize lateral play when slid into the miter tracks. They are secured to the sled with countersunk screws.

    The final procedure is to square the front fence to the blade. I use my 12" combination square and only able to get the right side squared to the blade. The left side has a tiny gap that I illustrated in the drawing below. The gap is exaggerated to make a point.

    This makes no sense to me. Either my combination square is not squared or the blade's thickness is not uniform. The fence is flat as it is jointed. I am certain I am not seeing something very obvious. But what?

    To make matter worse, I used the sled to cut a square panel about 8" x 8". One edge is jointed first. The remaining edges are cut, referencing the previous edge. The first two corners are square. The third corner is off by a tiny, tiny bit. The fourth corner is off by a larger amount. So I concluded that my sled is not square.

    I went back and check with my combination square. The picture below tells that story.
    Attached Files

  • #2
    Re: Out of square

    I'm guessing that either you've jointed a wedge or else your fence isn't really flat after being bolted/screwed down. Does your 12" straight edge actually lie perfectly flat against the fence when straddling the blade?

    Comment


    • #3
      Re: Out of square

      Check your square to make sure it is square.
      SSG, U.S. Army
      Retired
      K.I.S.S., R.T.F.M.

      Comment


      • #4
        Re: Out of square

        run that fence thru a planer.

        Comment


        • #5
          Re: Out of square

          Running the fence through a planer would only make sure that both sides of the fence are parallel to one another.

          If the fence face is not straight, it needs to be jointed.

          Comment


          • #6
            Re: Out of square

            I don't have a long precision straight edge to check the flatness of the fence, but I assume that a jointed surface should be flat and straight. My 12" combination square straight edge is flat against the fence when I check.

            I am planing to fix this problem starting with re-aligning the table saw. My guess is that the blade is old and wrapped in certain place, so I have ordered a new blade and will use it to re-align the saw once it gets here.

            I also need to make a better calibration base for the dial indicator.

            Comment


            • #7
              Re: Out of square

              You can make your own straight edge at whatever length you need (although its easiest to do less than 8', and grows in difficulty with length..

              Cut three 3" wide strips of good quality plywood (1/2" will work for shorter, but 3/4 better for long ones). Square one edge and mark it on each board. Put the first board with marked edge up in a vise or other stationary holder, and set the 2nd board with the marked edge down on top of the first one. Put a spring clamp on the ends to keep the edges parallel. If you see no light looking through the seam, you are good. If you do see light, mark the areas where they boards touch and sand/plane them down until the edges are flush. Repeat with board 3 on board 1. Then do 2 & 3. If you have to redo 2 & 3, go back and match them to 1. When all three match interchangeably, they are all straight.

              Save one for a master reference, and the other two can be used for set-ups, as a fence for a circular saw guide, etc. Take one to the borg when buying a level (most are not straight. You can also match the levels there until you get 3 that match, all of which will be straight.)

              It is tedious to do, but worth it in the long run. The basis for this is that you cannot match three different edges along their entire length unless they are straight.

              Go
              Practicing at practical wood working

              Comment


              • #8
                Re: Out of square

                In my opinion, combination squares suck, and if I'm looking at your drawing correctly, that is your problem.

                Go to a industrial supplier and buy a 6" machinist/tool & die square. They are made out of S.S. and are certified and calibrated to within .0002" of 90 degrees.

                Get one that comes in a wood box (quality) like from a company called Starrett or Mitsubishi. They have a knife edge that does not camoflage your eyesite when looking for light.

                You'll be amazed on how square/perpendicular you can tune things in. Like a tablesaw, Chopsaw, drill press table, bandsaw etc.

                Just handle it with kid gloves.

                Comment


                • #9
                  Re: Out of square

                  What I'm referring to is most cheap combination squares are useless for checking "dead-on" squareness. They are fine for measuring and layout. Just don't try to measure perpendicularity when trying to set machinery precisely. These things are made cheaply and are of high production chinese, big box junk.

                  Comment


                  • #10
                    Re: Out of square

                    Ditto that. Hard to find a "square" square and a "level" level anymore. So far, Starrett has not let me down, but haven't bought from them in a while. It is always best to keep a "reference" instrument that is just used to verify/adjust your "work" tools.

                    Go
                    Last edited by Gofor; 01-07-2010, 12:36 AM.
                    Practicing at practical wood working

                    Comment


                    • #11
                      Re: Out of square

                      Originally posted by vnh View Post
                      I spent a few hours today retrofitting my cross cut sled for the R4511. I built it originally to use with the TS2400. I removed the front fence (closer to me) and jointed two edges on the JP0610. The wooden runners received screws on their sides to minimize lateral play when slid into the miter tracks. They are secured to the sled with countersunk screws.

                      The final procedure is to square the front fence to the blade. I use my 12" combination square and only able to get the right side squared to the blade. The left side has a tiny gap that I illustrated in the drawing below. The gap is exaggerated to make a point.

                      This makes no sense to me. Either my combination square is not squared or the blade's thickness is not uniform. The fence is flat as it is jointed. I am certain I am not seeing something very obvious. But what?

                      To make matter worse, I used the sled to cut a square panel about 8" x 8". One edge is jointed first. The remaining edges are cut, referencing the previous edge. The first two corners are square. The third corner is off by a tiny, tiny bit. The fourth corner is off by a larger amount. So I concluded that my sled is not square.

                      I went back and check with my combination square. The picture below tells that story.

                      The first thing I would check is the most obvious to me: is your square actually square?
                      Bert

                      Comment


                      • #12
                        Re: Out of square

                        B2rtch: My square is square. I checked it by doing the draw-a-line-the-flip method. I also used a 0.5 mechanical pencil.

                        I have my eye on a Starrett combination square. Probably the 12". However, there are other pressing matters that take priority over the Starrett.

                        I think I am going to start from zero and build another cross cut sled for the R4511. I recently acquired some UHMW plastic that needs to be used for runners!

                        Comment

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