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  • Can't cut straight line on TS

    I am trying to cut straight edges on my table saw to glue up a larger panel. I have had to adjust my fence parallel to the saw blade but when I cut the boards and place them together there are gaps in the center as if the blade were cutting in an arc rather than a straight line so the ends meet but the middle does not.

    Something is out of alignement but I am not sure what would cause this odd arc in the cut.

    Ideas?

  • #2
    Re: Can't cut straight line on TS

    Two things that come to mind are improperly feeding the lumber through the blade or you have not edge jointed one edge of your boards before ripping to size. Either one of those could cause the troubles you're having.
    Teach your kids about taxes..........eat 30 percent of their ice cream.

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    • #3
      Re: Can't cut straight line on TS

      I agree with Dave. The need for a reference edge to start with was my first thought. If you don't have a jointer or a hand plane, you can try this method:

      Comment


      • #4
        Re: Can't cut straight line on TS

        I also agree. While I'm relatively new (only about three years now) with my use of the table saw, it would appear that your board is bowed and even though you may be sliding the board with attention to maintaining it against the fence you are getting that arc or bow.

        So while the edge you wish to join is showing a gap at the middle, what does it look like if you flip it over to the other edge... does it then show gaps at the outer edges?

        CWS

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        • #5
          Re: Can't cut straight line on TS

          I like this idea! I guess I know what jig I'm building tonight. Thanks for sharing.

          As for a bowed cut, if the reference edge is indeed straight, then I would question the arbor runout, the blade (thin kerf or low quality blade or not sharp) or possibly the fence face.

          What blade are you using? What fence are you using (Biesmeyer, Shop Fox, Delta..... What material is the fence face made from).

          The blade and fence should be aligned parallel to the miter slot.
          Last edited by SpiffPeters; 02-23-2010, 12:57 PM.

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          • #6
            Re: Can't cut straight line on TS

            They were precut and had flat edges to begin with but I wanted them smoother for gluing. The board may have had a bend to it but I cut both sides of three boards and had the same result on all of them.

            I have a Jet jointer/planer combo I just picked up but the jointer outfeed table needs aligning and I have to find the manual to figure it out.

            I need to order a good straight edge and a saw gauge to help align the TS blade and fence. Have to wait until I get paid Thursday to order anything.

            I am using the Ridgid R4511 table saw and the original fence it came with.
            I have not been too happy with this saw so far.
            I just bought an Incra mitre gauge and while setting it up found that the left hand miter slot is not uniform in width. If the gauge is setup to fit well for most of the track it binds at the front of the table.

            The fence could still be out slightly at one end but it is close. I have no added face to it just bare metal at the moment.

            It just struck me as odd that both sides of three pieces had the same result on these cut boards.

            Comment


            • #7
              Re: Can't cut straight line on TS

              Originally posted by the_nite_owl View Post
              They were precut and had flat edges to begin with but I wanted them smoother for gluing. The board may have had a bend to it but I cut both sides of three boards and had the same result on all of them.

              I have a Jet jointer/planer combo I just picked up but the jointer outfeed table needs aligning and I have to find the manual to figure it out.

              I need to order a good straight edge and a saw gauge to help align the TS blade and fence. Have to wait until I get paid Thursday to order anything.

              I am using the Ridgid R4511 table saw and the original fence it came with.
              I have not been too happy with this saw so far.
              I just bought an Incra mitre gauge and while setting it up found that the left hand miter slot is not uniform in width. If the gauge is setup to fit well for most of the track it binds at the front of the table.

              The fence could still be out slightly at one end but it is close. I have no added face to it just bare metal at the moment.

              It just struck me as odd that both sides of three pieces had the same result on these cut boards.
              It's doubtful if the saw is at fault, but not impossible. Fence to blade parallelism won't cause the problem you're seeing. However, you should take a known straightedge and put it against the fence where the board rides. If the fence isn't straight this will give you the problem you're seeing. I imagine this would be a rare problem but who knows, it may have been damaged somehow.

              If your board is bowed in the plane of the table... that will cause the problem. Often boards sold with one factory or mill edge have bowed by the time you get the wood and use it. Cutting both sides won't help. You will have to straighten the edge.

              Another easy jig that can be used to joint a board on the tablesaw is simply a piece of plywood, with a factory edge. The factory edge is pretty good on plywood. Put a few holes in the ply with counterbores on the underside and install carriage bolts, with a securing nut through the top. Make a few toe clamps out of scrap hardwood and use this to clamp your board to the plywood. Put the plywood factory edge against the fence and take a very light pass or two or three. A standard kerf (not thin) blade works best for this if you have one. When your blade cuts along the entire edge, the board is as straight as the factory plywood edge, which is good. This assumes that your fence itself is straight of course.

              Another easy thing to do is to joint one edge using a router and a long straight edge clamped to the board as a guide. This works particularly well when the board is wide enough to support the router base. You have to use a known straightedge - not a 2x4 or other board. I don't have a jointer anymore and feel that I get at least as good of edges - probably better - with these two techniques as I did when I used a jointer.

              By the way you don't need a fancy gage to align your TS fence to the blade. There area lot of gizmos you can buy in wooodworking that you really just don't need to do top quality work. Instead, get a 12" machinist's scale from the local industrial supply. Starrett is about $90, but an SPI brand works just as well and is about $15. You'll find you will use it a lot for all kinds of things in woodworking. Get one graduated in 64ths and 32nds on one side, 50ths and 100ths on the other side. Then, mark one tooth on the blade with a sharpie, roll the blade to the front, use the scale to measure from the point of the tooth to the fence. Then roll the blade to the back and measure again on the marked tooth. That's it. You want the blade dead parallel to the miter slot, but the fence needs a tiny bit of toe - fence further from the blade at the back than the front - to prevent excessive burning and reduce the potential for kick-back, around 0.010 to 0.020.

              Comment


              • #8
                Re: Can't cut straight line on TS

                I agree with others, you need to make sure the side that rides against the fence is straight otherwise you're just going to copy the imperfections to the edge you're cutting. Also, make sure your fence is dead straight and flat, use a level to make sure it hasn't warped or gotten dinged as your cut will only be as straight as the straightedge you're using.

                Comment


                • #9
                  Re: Can't cut straight line on TS

                  I bought a good straight edge and found that my fence is bowed by a little more than .007 in the center so as the piece rides along the fence it dips away from the blade and then pushes back in again as it reaches the back of the fence.

                  I am going to clamp my straight edge to the table parallel to the blade and see how the cuts come out. If it cuts fine then that rules out any other issues but this fence being bowed is a serious issue and the third major problem I have had with this TS.

                  Comment


                  • #10
                    Re: Can't cut straight line on TS

                    I will suggest some thing set the fence with a little clearance on the back side of the saw,
                    set a 64 to a 32 of an inch on the back side, from where the front is set. and see if that helps any. YES I AM SUGGESTING TO NOT SET YOUR FENCE SQUARE WITH THE BLADE. give the blade some clearance, (I have only been running my old walker turner saw that way for what 40+ years, and have built any thing from custom kitchen cabinets to a violin, and many many other items in between,

                    I can tell you some thing .007 of an inch in 30 inches on a table saw is not a problem, IMO

                    If you want to cut in the thousands then you need a different medium than wood. IMO.

                    how crooked is not straight,

                    how do you know it is not your wood being relived of tension? even a piece of properly dried wood is moving with the environment it is in on a daily basis, when ever it is worked it moves as some of the cells on one side have been removed,
                    that is why planing some thing from both sides is usually consider correct, as it keep the surface moistures and tensions equal,
                    (it may be like a bi metal thermostat, you saw off one edge it take the equalized edge off and the wood will bows
                    Push sticks/blocks Save Fingers
                    ~~~~~~~~~~~~~~~~~~~
                    "The true measure of a man is how he treats someone who can do him absolutely no good."
                    attributed to Samuel Johnson
                    ~~~~~~~~~~~~~~~~~~~
                    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                    Comment


                    • #11
                      Re: Can't cut straight line on TS

                      Originally posted by BHD View Post
                      I will suggest some thing set the fence with a little clearance on the back side of the saw,
                      set a 64 to a 32 of an inch on the back side, from where the front is set. and see if that helps any. YES I AM SUGGESTING TO NOT SET YOUR FENCE SQUARE WITH THE BLADE. give the blade some clearance, (I have only been running my old walker turner saw that way for what 40+ years, and have built any thing from custom kitchen cabinets to a violin, and many many other items in between,

                      I can tell you some thing .007 of an inch in 30 inches on a table saw is not a problem, IMO

                      If you want to cut in the thousands then you need a different medium than wood. IMO.

                      how crooked is not straight,

                      how do you know it is not your wood being relived of tension? even a piece of properly dried wood is moving with the environment it is in on a daily basis, when ever it is worked it moves as some of the cells on one side have been removed,
                      that is why planing some thing from both sides is usually consider correct, as it keep the surface moistures and tensions equal,
                      (it may be like a bi metal thermostat, you saw off one edge it take the equalized edge off and the wood will bows
                      This saw is less than a year old and the fence should be replaced with one that does not bow.
                      I know that .007 is not a lot but it is amplified when both pieces of wood are cut and becomes .014. Trying to cut a glue edge with that large a gap does not look good and even if I can make it work I should not have to on a a new saw that should have tighter tolerances.

                      The wood may be moving after the cut but the point here is that a straight edge against the fence shows a gap in the middle of the fence and that gap is causing me problems trying to cut a nice straight glue edge.

                      I may be able to get a nice flat piece of stock to mount against the fence as a sacrificial fence and shim in the middle so there is no deflection but I have had so many problems with this saw I want the fence replaced.
                      I had to go back to the store once with a defective left wing and bring the saw 30 miles away to a service center twice for other issues.
                      I understand why this model was so quickly discontinued.

                      Comment


                      • #12
                        Re: Can't cut straight line on TS

                        All I can say is I am sorry your saw has not preformed to your expectations,


                        all I can say is get your jointer fixed and use it.

                        how long are these boards your cutting?
                        Push sticks/blocks Save Fingers
                        ~~~~~~~~~~~~~~~~~~~
                        "The true measure of a man is how he treats someone who can do him absolutely no good."
                        attributed to Samuel Johnson
                        ~~~~~~~~~~~~~~~~~~~
                        PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                        Comment


                        • #13
                          Re: Can't cut straight line on TS

                          Originally posted by BHD View Post
                          All I can say is I am sorry your saw has not preformed to your expectations,


                          all I can say is get your jointer fixed and use it.

                          how long are these boards your cutting?
                          Yeah, working on the jointer.
                          The boards are short so the problem shows up more. Could cut some long ones and end up taking a feet or so off each end to have a good clean cut but...
                          May end up making myself a jig for jointing as was suggested earlier in the thread. I have all the parts, just need a good piece of ply for the base.

                          Comment


                          • #14
                            Re: Can't cut straight line on TS

                            I glue up wood with gaps much larger than a paltry .014". By reversing the bows and clamping them tightly, all the gaps are gone and the stresses equal out. I rarly take the time to get the wood so flat that I can glue it up without clamps, I don't have that kind of time. Most of the woods I work with move that much in a day here in Louisiana where the humidity and tempurature constantly change. I have a load of the African mahogany that warps worse the more you cut it. I still run the original fence on my saw and have very good results.

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