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  • Edge finders

    Are the electronic edge finders any better than just using the old fashion wiggler. I can pick up an edge with an accuracy of .0005", usually with consistent repeatably, will the electronic type equal that, are they better or worse.

    It appears that they would be faster in use for multiple checks then a wiggler but I don't want to give up accuracy.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

    Southwestern Ontario. Canada

  • #2
    I use both kinds and each has it's advantages and disadvantages. The "click" style are, of course, used while rotating. But I do not run the motor for the electronic style.

    A good "click" style finder is both easy to use and accurate. But it is not ideal for every edge. I find they do not work as well on curved edges if the radius is too steep.

    A good electric type is also easy and accurate. I routinely get 0.0005" accuracy with them, but a little exrta care is needed. They will work on round edges, both concave and convex. Of course they work on straight edges too. As for disadvantages, in addition to needing batteries and the occasional new bulb if not an LED model, they are not very forgiving of overtravel after they come in contact with the edge. Their center pins can be pushed to one side and even be bent. So, you must be very careful. Also, they are usually off by several tenths, probably due to past crashes, so you must take one reading, back off and rotate the spindle 180 degrees and take a second one. The set point is half way inbetween. This is fairly fast, with practice, but not as fast as a "click" style where overtravel is not harmful and you can approach the edge more rapidly, overshoot a bit, back up, and re-probe instantly to get a final reading.

    If you would like an example of a round edge that you would need to locate, see my post in the recent "Rotary Table Question" thread.
    Paul A.
    SE Texas

    Make it fit.
    You can't win and there is a penalty for trying!

    Comment


    • #3
      Hi,

      I use both types too. There are some electronic edge finders that will take over travel. I've got one.

      I don't find them any better or worse than spinner types. Except in two areas. First, with electronic you don't have to start the spindle for it to work. I find that to be a convenience for me sometimes. And secondly, I find electronic edge finders work better in the horizontal position. I do need to pick up an edge occasionally in a horizontal mill. Spinners are almost next to useless in that situation.

      They aren't really that expensive, so get one. It can be handy.

      dalee
      If you think you understand what is going on, you haven't been paying attention.

      Comment


      • #4
        If you want to position the spindle X distance from the edge of block to drill a hole, drill chucks aren't always accurately lined up with the center line of the spindle, the wiggler type will compensate for this error, does the electronic type or will in carry any error into the hole position.
        The shortest distance between two points is a circle of infinite diameter.

        Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

        Southwestern Ontario. Canada

        Comment


        • #5
          Originally posted by loose nut
          If you want to position the spindle X distance from the edge of block to drill a hole, drill chucks aren't always accurately lined up with the center line of the spindle, the wiggler type will compensate for this error, does the electronic type or will in carry any error into the hole position.
          If the electronic type is off center, it will read wrong. Read the procedure that I use in my post above: it exactly compensates for any error that they (and/or the chucking device) may have as long as the tip's diameter is exact.
          Paul A.
          SE Texas

          Make it fit.
          You can't win and there is a penalty for trying!

          Comment


          • #6
            Hi,

            OK, edge finders, spinners or electronic are different than a wiggler. Edge finders are meant to be used in a collet. They don't always work well on a drill chucks. Though I've cheated and done it.

            No edge finder type will easily compensate for a lot of chucking run out. You can do as Paul A. said, pick up the edge then rotate the spindle by hand 180 deg. and then pick it up again. Then difference between the two readings is the edge.

            Wigglers on the other hand are more tolerant of run out. But are some what of a pain in butt to use for me. I find them to not be as easily accurate as I want. Though for your scenario with a drill chuck, I'd use a wiggler rather than an edge finder.

            A decent ridged electronic edge finder will consistently give +/-.0002" in a good collet. Though I mostly use mine in a CNC mill. The spinners and spring loaded electronics will do about +/-.0005" if in good repair. And are better for use in manual machines.

            dalee
            If you think you understand what is going on, you haven't been paying attention.

            Comment


            • #7
              I use a cnc machine and the spindle ramps up too fast to use a wiggler - about 90% of the time it starts doing it's little dance when I either start of stop the spindle. A regular edge finder is much better and repeatable to +- .0005" if everything is clean, but I have now found something that is much faster and more accurate. Haff & Schneider ( http://www.haff-schneider.de/index.p..._id=32&clang=1 ) make a 3d analog touch probe that is just insanely accurate. It consistently agrees with the machine to .0001" and takes about 10 seconds to hit it. My regular edge finder went into the chest and has not come out since.

              Comment


              • #8
                Originally posted by dalee100
                Hi,

                OK, edge finders, spinners or electronic are different than a wiggler. Edge finders are meant to be used in a collet. They don't always work well on a drill chucks. Though I've cheated and done it.

                No edge finder type will easily compensate for a lot of chucking run out. You can do as Paul A. said, pick up the edge then rotate the spindle by hand 180 deg. and then pick it up again. Then difference between the two readings is the edge.

                Wigglers on the other hand are more tolerant of run out. But are some what of a pain in butt to use for me. I find them to not be as easily accurate as I want. Though for your scenario with a drill chuck, I'd use a wiggler rather than an edge finder.

                A decent ridged electronic edge finder will consistently give +/-.0002" in a good collet. Though I mostly use mine in a CNC mill. The spinners and spring loaded electronics will do about +/-.0005" if in good repair. And are better for use in manual machines.

                dalee
                It is not true that a "click" type edge finder depends on being held with low run out in a collet. That type of edge finder only depends on the fact that the tip is "pushed" past the actual center of rotation by the edge of the work piece.

                When the tip's center of rotation has not yet reached the edge, it will wobble in ever smaller circles as this condition is approached. At the point where the center of rotation is directly over the edge, it's tip will rotate exactly on center, even if it must change position relative to the body of the finder. Once you pass this point, the tip experiences constant frictional force from rubbing against the work and this produces the motion away from that center point. It should be held very close to parallel to the axis of rotation, but does not depend on the mounting means having low run out. This should not be carried to extremes, but a run out of a few thousanths should make no difference. This is probably one of the reasons why these simple edge finders have been so successful. It is essentally a self compensating - self calibrating instrument. And it doesn't have any electronics. Wonder of wonders. It took me quite a while to realize just how well these little jewels are designed. And no one seems to ever have explained just how they do work: I have looked and found nothing.

                On the other hand, the electric types DO rely on both the accuracy of the finder itself and on the means by which it is mounted. The total run out from all sources will contribute to error. That is why it is important to take two readings with the spindle rotated by 180 degrees and using the point half way between them.
                Last edited by Paul Alciatore; 10-26-2009, 03:32 AM.
                Paul A.
                SE Texas

                Make it fit.
                You can't win and there is a penalty for trying!

                Comment


                • #9
                  Originally posted by MickeyD
                  I use a cnc machine and the spindle ramps up too fast to use a wiggler - about 90% of the time it starts doing it's little dance when I either start of stop the spindle. A regular edge finder is much better and repeatable to +- .0005" if everything is clean, but I have now found something that is much faster and more accurate. Haff & Schneider ( http://www.haff-schneider.de/index.p..._id=32&clang=1 ) make a 3d analog touch probe that is just insanely accurate. It consistently agrees with the machine to .0001" and takes about 10 seconds to hit it. My regular edge finder went into the chest and has not come out since.

                  Odd that in the technical Data chart they show that .01 mm = .004"

                  Comment


                  • #10
                    Originally posted by Uncle O
                    Odd that in the technical Data chart they show that .01 mm = .004"
                    Classic typo!

                    .01mm = .0003937"

                    Comment


                    • #11
                      If you want the worlds best edge finder, get one of these beauties:

                      https://www.hschmidt.com/productcart...&idproduct=148

                      At $45. its worth it, definitely the nicest piece of tooling I have in my shop, I sold all my electronic ones after getting this one.

                      Paul T.

                      Comment


                      • #12
                        Originally posted by PaulT
                        At $45. its worth it, definitely the nicest piece of tooling I have in my shop, I sold all my electronic ones after getting this one.
                        Paul T.

                        Yes, but will it survive that accidental extra 1/2 turn of a dial in the wrong direction?? I've lost more than one edge finder that way............sorta like sawing off your tape measure in the horizontal band saw.

                        Comment


                        • #13
                          Another vote for Herman Schmidt. Using that one, I don't even think about edge finders anymore.

                          Comment


                          • #14
                            Originally posted by tdkkart
                            Yes, but will it survive that accidental extra 1/2 turn of a dial in the wrong direction?? I've lost more than one edge finder that way............sorta like sawing off your tape measure in the horizontal band saw.
                            I almost cried when I thought I busted the first one I had, but it turns out I had just snapped the pin off that holds the spring, and after I conveyed my sob story to HS they sent me a new pin no charge.

                            I bought a second one as a backup, so far its stayed on the sidelines.

                            Paul T.

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