How square is square enough?

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  • trungdok
    Established Member
    • Oct 2012
    • 235
    • MA

    How square is square enough?

    Not really a true question, but just want to hear everyone's opinion on the subject. Recently, I built a couple of miter slots to the right side of the blade on my BT3100 and a sled. I used the 5 cuts squaring method to square my fence with the blade as much as I can (using wood shavings to offset the fence bit by bit). After drilling many holes, I seem to only be able to get a square that is between 1/128" to 1/64" off every 24". I tried to get it more square, but feeling that I'll only making it worse. In my head, I think it's square enough, but at the same time, I must admit, I drives me a bit crazy not being able to do better.

    Anyway, how square is square enough for you, the more experienced woodworkers?
  • chopnhack
    Veteran Member
    • Oct 2006
    • 3779
    • Florida
    • Ryobi BT3100

    #2
    Square enough depends on the project. The larger the project, i.e. greater distances between pieces that intersect, the more important it is to be precise. If you have it down to 1/128 or 1/64 over 2' that should be ample for woodworking IMHO. Perhaps others will chime in soon with their experiences.
    I think in straight lines, but dream in curves

    Comment

    • JR
      The Full Monte
      • Feb 2004
      • 5633
      • Eugene, OR
      • BT3000

      #3
      I'm with Chopnhack, you should be good to go for most projects. If you want to do really fine joinery, you could make a cross-cut sled and it will smooth out any rough spots.
      JR

      Comment

      • woodturner
        Veteran Member
        • Jun 2008
        • 2047
        • Western Pennsylvania
        • General, Sears 21829, BT3100

        #4
        Originally posted by trungdok
        In my head, I think it's square enough, but at the same time, I must admit, I drives me a bit crazy not being able to do better.

        Anyway, how square is square enough for you, the more experienced woodworkers?
        It really is a subjective thing. I tend to be a bit of a perfectionist, and really don't like seeing gaps. Still, 1/128" in a 24" span is pretty good, and won't be visually detectable in spans up to 6" or so, the resolution of the eye is insufficient in most cases to see that gap without magnification.

        The real trick, though, is to design and cut the pieces so that any error is not visible. For example, if you cut the two halves of a miter on opposite sides of the blade, any minor difference in angle will be complemented on the opposing piece, and the joint will be tight, even if the cut angle is not exactly 45 degrees.

        The human eye excels at detecting even slight differences between straight lines and contrasting colors - so don't put those in your projects. Most furniture, for example, hides the more troublesome joints behind molding or otherwise avoids the kinds of joints were we can visually detect a 1/128" gap.
        --------------------------------------------------
        Electrical Engineer by day, Woodworker by night

        Comment

        • Carpenter96
          Established Member
          • Aug 2011
          • 178
          • Barrie ON Canada
          • BT 3000

          #5
          I too am a perfectionist when it comes to set up but for most things 1/128" over 24" should be fine.
          Regards Bob

          Comment

          • cwsmith
            Veteran Member
            • Dec 2005
            • 2737
            • NY Southern Tier, USA.
            • BT3100-1

            #6
            It often makes me laugh at the challenges that I sometimes get faced with. Some things that sound so simple are too often not simple at all. "Making it square" is one of those.

            I remember when I first started out on the drawing board, there was the challenge of drawing a simple line with graphite... how to make it just the right width and have it consistant over the several inches it might be required. So simple a quest, but it was daunting at the time.

            So too is the "square" cut on the different saws that I might use. The RAS, my favorite saw, just seems to be a challenge. While I can get the fence square with the arm easy enough, the blade-to-table angle seems to be really elusive and it took me some time to straighten that out. I found it not to be so much the alignment of blade-perpendicular to the table, but a matter of the blade heel. That took some effort. Even now it's not perfect, and I'm still not happy.

            The Ridgid 10" CMS is okay and highly accurate, except for those darn bevel crosscuts. Try as I might, I simply can't get anything consistant there, even on narrow stock. I find the best way is to simply stand the stock on edge and make a simple miter cut. Not sure if it's blade flex or just a poor design of pivot point.

            My BT3100... well now there is a tool. I have yet to have a single problem on ripping. Crosscuts are okay, or at least to a point that I can't pin to my own fault of having the stock slip against the miter fence. I must admit though that I much prefer to do cross-cuts on the RAS though.

            "How close" is the question. I don't have an answer, except perhaps to say that my projects so far haven't fallen apart and they remain level and plumb and the joints mate nicely. But perhaps everything I do is fairly simple though, like a couple of tables, and lots of book cases.

            Frankly, I don't measure in small fractions. I use a square, and if it looks okay and I see no gaps full of light, then it's acceptable. I don't make boxes, but do make drawers. "Square" is thus essential for a good fit. My "eye" is my best measure of "how close" I think. So, at least in my world I think I'm okay.

            CWS
            Last edited by cwsmith; 09-29-2013, 10:47 AM.
            Think it Through Before You Do!

            Comment

            • jabe
              Senior Member
              • Apr 2006
              • 566
              • Hilo, Hawaii
              • Ryobi BT3000 & Delta Milwaukee 10" tilting Table circular saw

              #7
              1/128 or 1/64 is GTG . Material expand and contract, your saw blade expand & contract as it heats up & cool dn. If U tighten your blade arbor nut too tight it'll cause your blade to wobble slightly. Don't loose sleep over this, 1/128" on 24" is square enough.

              Comment

              • greenacres2
                Senior Member
                • Dec 2011
                • 633
                • La Porte, IN
                • Ryobi BT3000

                #8
                Originally posted by cwsmith
                The Ridgid 10" CMS is okay and highly accurate, except for those darn bevel crosscuts. Try as I might, I simply can't get anything consistant there, even on narrow stock. I find the best way is to simply stand the stock on edge and make a simple miter cut. Not sure if it's blade flex or just a poor design of pivot point.

                CWS
                I've got the same trouble with bevels on the DW718. The settings are all dead on with the blade stopped, I've not checked with the blade spinning!! In my opinion--at least for me--the bevel issue may stem from the stock moving as I cut. The slightest movement could be a half degree, then it's compounded on another piece. Like you, when I stand it on edge, it's spot on--so it seems I could take my set-up tools out of the equation. If they were wrong, the miter cuts would be wrong too. Blade flutter may be a little different on the bevel plane as well--even if it's not measurable when the blade is spinning 90 degrees to the table.

                I need to try some bevels with hard core clamping of the stock to test that theory!!

                Just my thoughts--your mileage may vary.

                earl

                Comment

                • cwsmith
                  Veteran Member
                  • Dec 2005
                  • 2737
                  • NY Southern Tier, USA.
                  • BT3100-1

                  #9
                  I read somewhere a few years ago (when first looking at this problem) that this was the "nature of the CMS"... apparently the author of that statement felt that the pivot design simply could not hold the angle properly. The statement went on to day only a RAS could give you a consistant bevel angle cut.

                  I won't pretend to be that versed in such things, but it didn't sound all that logical to me. But, I certainly don't have such that problem with my RAS.

                  My Ridgid 10" CMS actually has a clamping device to hold the stock... using it, I still have the problem, and I see no way to adjust to get rid of it. To some degree, I believe it might be blade flex, but even there I have doubts.

                  I have found that if the stock is narrow enough, you can simply stand it on edge and cut the compound angle or bevel that way, and do so with some consistancy.

                  CWS
                  Think it Through Before You Do!

                  Comment

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