Miter gauge tolerance

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  • jussi
    Veteran Member
    • Jan 2007
    • 2162

    #1

    Miter gauge tolerance

    Used a dial indicator to measure how parallel my miter gauge is to my blade. Depending on which tooth I measure from the tolerance range from .005 to .01 inches

    Is that acceptable?
    Last edited by jussi; 02-12-2009, 01:11 PM.
    I reject your reality and substitute my own.
  • Tom Slick
    Veteran Member
    • May 2005
    • 2913
    • Paso Robles, Calif, USA.
    • sears BT3 clone

    #2
    I prefer to measure to the plate, it takes the variability out of the tooth alignment.
    Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison

    Comment

    • jonmulzer
      Senior Member
      • Dec 2007
      • 946
      • Indianapolis, IN

      #3
      Originally posted by jussi
      Depending on which tooth I measure from the tolerance range from .005 to .01 inches
      Why are you not using the same tooth for front and back measurements?? What saw? What miter gauge?
      "A fine beer may be judged with just one sip, but it is better to be thoroughly sure"

      Comment

      • poolhound
        Veteran Member
        • Mar 2006
        • 3196
        • Phoenix, AZ
        • BT3100

        #4
        To measure the alignment of a fence or miterslot/gauge you really need to mark a single tooth and the rotate the blade and measure front and back.

        You may also have arbor issues to contend with that are nothing to do with the actual parallel or straightness of a slot or fence.
        Jon

        Phoenix AZ - It's a dry heat
        ________________________________

        We all make mistakes and I should know I've made enough of them
        techzibits.com

        Comment

        • jussi
          Veteran Member
          • Jan 2007
          • 2162

          #5
          I'm using the same tooth for one measurement. Measure it once with the tooth in the front and once to the back. But then I took another tooth and did the whole thing over again. Each measurement resulted in about .01 difference (no matter which tooth) but the actual distance between miter gauge and tooth changed depending on which tooth I took. I'm guessing there's a bit of runout from the blade.

          I asking what's the acceptable tolerance. As I said right now I'm getting about .01
          I reject your reality and substitute my own.

          Comment

          • ragswl4
            Veteran Member
            • Jan 2007
            • 1559
            • Winchester, Ca
            • C-Man 22114

            #6
            Originally posted by jussi
            I'm using the same tooth for one measurement. Measure it once with the tooth in the front and once to the back. But then I took another tooth and did the whole thing over again. Each measurement resulted in about .01 difference (no matter which tooth) but the actual distance between miter gauge and tooth changed depending on which tooth I took. I'm guessing there's a bit of runout from the blade.

            I asking what's the acceptable tolerance. As I said right now I'm getting about .01
            On a crosscut I would guess that's accurate enough. 1/64" = 0.015625. On very long rips (if this same error occurs between the blade and the fence) you might have a problem with fitment. If possible try another blade and also measure the blade to fence parallelizm (is that a word?) to narrow it down to the unusual suspect. I agree with your approach to use the same tooth for measuring the front and back of the miter slot.

            After rereading your OP I would try a different (new if possible) blade to eliminate that as the source of difference. Ensure there is no debris (sawdust, etc) between the inner arbor plate and the blade. What kind of saw?
            RAGS
            Raggy and Me in San Felipe
            sigpic

            Comment

            • jussi
              Veteran Member
              • Jan 2007
              • 2162

              #7
              Originally posted by ragswl4
              On a crosscut I would guess that's accurate enough. 1/64" = 0.015625. On very long rips (if this same error occurs between the blade and the fence) you might have a problem with fitment. If possible try another blade and also measure the blade to fence parallelizm (is that a word?) to narrow it down to the unusual suspect. I agree with your approach to use the same tooth for measuring the front and back of the miter slot.

              After rereading your OP I would try a different (new if possible) blade to eliminate that as the source of difference. Ensure there is no debris (sawdust, etc) between the inner arbor plate and the blade. What kind of saw?
              Craftsman 22114
              I reject your reality and substitute my own.

              Comment

              • ragswl4
                Veteran Member
                • Jan 2007
                • 1559
                • Winchester, Ca
                • C-Man 22114

                #8
                Originally posted by jussi
                Craftsman 22114
                Same saw that I have. I'll go measure mine using the same method and get back to you asap.
                RAGS
                Raggy and Me in San Felipe
                sigpic

                Comment

                • radhak
                  Veteran Member
                  • Apr 2006
                  • 3061
                  • Miramar, FL
                  • Right Tilt 3HP Unisaw

                  #9
                  I read somewhere that acceptable is 0.003 to 0.007, and immediately checked my TS : worked out to 0.010 to 0.011 inches .

                  So while mine was way beyond 'acceptable', it was more consistent than yours . I'd guess you could try a different blade.

                  I have not attempted to fix mine - read up on the procedure and got sorta intimidated. Most of my cuts seem to come off okay - to me!
                  It is the mark of an educated mind to be able to entertain a thought without accepting it.
                  - Aristotle

                  Comment

                  • ragswl4
                    Veteran Member
                    • Jan 2007
                    • 1559
                    • Winchester, Ca
                    • C-Man 22114

                    #10
                    Ok here are the numbers.

                    1. Front to back measurement on same tooth was .002 difference.
                    2. I then moved the blade around and measured each tooth and largest difference was .005 while the nominal difference was .002 with some teeth measuring exactly the same as others.

                    Used dial indicator and Freud blade. I am getting very square cuts with an Incra miter gauge (V-27) and rips are +/- .001 in most cases using the stock fence (I like it).
                    RAGS
                    Raggy and Me in San Felipe
                    sigpic

                    Comment

                    • LCHIEN
                      Super Moderator
                      • Dec 2002
                      • 21709
                      • Katy, TX, USA.
                      • BT3000 vintage 1999

                      #11
                      if you are trying to get below .01" in measuring, technique will have a lot to do with it. Pressing lightly on the blade can easily deflect it .005 I am thinking. You need to make sure there is absolutely no slop in the miter gauge track and the fixture for holding the dial gauge can not lean forwards or backwards (towards the blade) the slightest amount or that's probably another .005 or more.

                      As I just said, very technique sensitive.
                      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

                      • Relative
                        Established Member
                        • Mar 2007
                        • 109
                        • Garden Grove, CA
                        • Ridgid R4512

                        #12
                        Try this technique:

                        http://www.woodshopdemos.com/align-1.htm

                        Mike
                        Veterans are people who, at one point in their life, wrote a blank check payable to the United States of America, for an amount up to and including their life.

                        Comment

                        • jussi
                          Veteran Member
                          • Jan 2007
                          • 2162

                          #13
                          Originally posted by radhak
                          I read somewhere that acceptable is 0.003 to 0.007, and immediately checked my TS : worked out to 0.010 to 0.011 inches .

                          So while mine was way beyond 'acceptable', it was more consistent than yours . I'd guess you could try a different blade.

                          I have not attempted to fix mine - read up on the procedure and got sorta intimidated. Most of my cuts seem to come off okay - to me!

                          The way I planned on correcting it was to unscrew 3 of the 4 bolts holding the table and just hit one of the corners. Kind of a brute force way to adjust something 1000ths of a inch but it's the only way I know how to do it.


                          Sad thing is it's a WWII blade so I thought it should be pretty accurate. I got it used though from a garage sale so who knows what abuse it went through.
                          Last edited by jussi; 02-12-2009, 08:14 PM.
                          I reject your reality and substitute my own.

                          Comment

                          • cabinetman
                            Gone but not Forgotten RIP
                            • Jun 2006
                            • 15216
                            • So. Florida
                            • Delta

                            #14
                            I hate to say this, but I don't use fancy falootin' gauges or dial indicators to do a table saw alignment. They are probably pretty cool things to have and use if they are in the budget. The only time I'm concerned with numbers to the right and sometimes left of the decimal is with my blood alcohol content.

                            I keep in mind this ain't tool and die making, it's woodworking. Heck, I could show up to the shop at 7 AM, cut up some stuff, and by noon it's a different size.

                            With a mounted blade, I first crank the blade all the way up, and set it for 90 deg and check it with a drafting template. Then, I check to see if the blade is parallel to the miter slot. How do I do that you ask? Well it's easy, with the blade all the way up, I measure from the front and rear of the blade to the edge of the miter slot. If the distance is the same, I then mark one tooth, and rotate the blade so the tooth is in the front, and measure to the slot, and then rotate it to the back and measure to the slot. If there is a differential it could be in the blade, or the arbor on back. Watching a cut with an 1/8" tooth kerf may be an indicator if the cut is lookin' a bit wide. The sound of the blade may change, or the amount of vibration.

                            If everything is A-OK, I move on to the fence. That one is easy, I just lock it down and measure to the slot front and back, and if it's A-OK, I might go make a cup of coffee. If not, I start to figure out where in that order of things to shift or adjust to line it all up. I must be just lucky, because the work seems to come out OK.


                            .

                            Comment

                            • Pitman
                              Forum Newbie
                              • May 2005
                              • 9
                              • .

                              #15
                              Yep, I use the drafting triangle as well. I think I would go nuts trying to achieve perfection with a dial indicator.

                              Of course it's the end results that matter, so when I think everything is good, I will take a small piece of scrap plywood, rip cut two sides, then cross cut the other two. Then stand it up on end and check it with the drafting triangle.

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