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Edge finders and center finders?

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  • Edge finders and center finders?

    I have some edge finders and the directions for the "not pointed one" were in the package (bottom of finder jumps to the side 1/32 of an inch when edge of work is found). However, the "pointed one" had no directions for it's setup.

    Could someone please explain how the pointed one is supposed to be set up to find the center when using a center-punched location, and what behavior should I see from it when the center is found?

    Hummmm....the above questions sounds awkward but I hope you all understand what I'm asking.


  • #2
    good post iv used wigglers for center finding on a lay out and we have a new collet just for the edge finder and thats all we use it for.
    i guess the center finder end is just a wiggler and workes the same but use it gently doe to the spring will mess up if you are not very carefull.
    i use a good co axeal indicator to dial in bores after a sleave has been welded or pressed in and bored to size last.
    i have an old wiggler but never use it but can use it.
    that end of the edge finder no one ever uses and is a good thing for all of us to learn set up and use right.
    any advice will help all.
    its tricky.
    good luck!


    • #3
      Mike -

      I've always assumed that the pointed edge finders are made that way so you can get it into a narrow place like between two close parallel edges or the inside of a small hole and locate those edges. I don't think they're intended for use with a center punched mark. A wiggler and dial indicator would seem better suited to that job.



      • #4
        When I use the pointed end of the edge finder, I bring the quill down to where the point is just touching the bottom of the punchedhole, or the sides of a center drilled hole or whatever, then moving the table to center the edge finder by milking it. You would be surprised how sensitive your fingers are for this operation...OOPS forgot to mention, the machine is not running for this operation... Hope this helps...Jim


        • #5
          We've been using a center finder/edge finder indicator in our CNCs that works in the X Y Z axis. Slicker than you know what. But at over $400 it better be. Made in the fatherland and sold by SPI among others. 3D Tester IIRC
          Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


          • #6
            I find this end quite versatile, but have also had frustration in finding information on it. Shaque's method is similer to the one I use if what he's talking about is picking up the offset between the shaft and the short staight section of the point. With the point firmly but gently set in the punch mark or hole and the spindle off I use a finger nail or 6" flexible scale held against the shaft and hung up on the lip of the overhang. I slowly move the table until the nail/scale slips off. Repeat on the other axis, go back and confirm the first axis and your dialed in. This can also be done visualy with a moderatly powerd magnifying glass.

            This end is also extreamly useful in the lathe to align work in the four jaw chuck. place the edge finder in the tailstock and bring it up to the mark or hole in the workpiece. Using the above method or with a dial indicator heald against the point shoulder the work can be adjusted true.


            • #7
              I don't know if I read it somewhere or some one told me, but I've used the pointed end to locate centers of small holes and punch marks by first getting close using some of the above mentioned methods, then measuring across the joint with a micrometer in the x then y directions. adjust the table as needed to get to the nominal shaft dimension.


              • #8
                The way I was taught to use pointed edge finders are......
                1.start spindle
                2.Take a scale(or other suitable object)and use it to center point. You will be able to feel (also see)point running true.
                3.With spindle still running bring point about 1/32 above surface of part.You will then be able to bring point in line with center lines (or line) that is scribed on part.
                This is not an an extremely accurate way of locating holes on a part,but with some practice and careful layout,you will be able to hit the location within about .003 to .005

                ...the order of bringing about change
                is the four boxes:


                • #9
                  I've always used the pointed finder as Burnlast has described. I seem to remember being told that sighting on X,Y scribed lines with a true running point put you within +/- 0.002" (given reasonable 'shooters' eyesight!).

                  I would like to hear comments about the use of the 0.200" or 0.250" ball type wiggler though. As I have come across two variations of 'custom and practice' with this tool. The first system is as mentioned above where the wiggler is brought into contact and allowed to 'spin up' the face as the centre point of contact is reached (or could it be passed?). The other method I have known (and was taught to use during my apprenticeship!!) was to 'blue up' the ball wiggler and watch for a 'clean wipe'. This system is supposed to be more accurate (within 0.001" for repeatability and accuracy) whereas the former method tended to be likely to be almost always 0.001"/0.003" past centre with similar repeatability.

                  I have a Starrett wiggler, as well as a Huffman, and an electronic light emitting edge finder. When I first got the electronic finder I thought it was a neat tool - but somehow I've drifted back to using the wiggler as my preferred method of edge finding. The Starrett and Huffman are quality tools and both have a very even resistence to the offset ball knuckle.



                  • #10

                    Why did you "drift" back to using the wiggler, when you had an electronic edge finder? I been think of getting one of those electronic version so any comment would be useful. Thanks.



                    • #11
                      The Starrett Catalog describes the use of the pointy end as described by burnlast. I have also heard of the 0.002" accuracy in "eyeballing".
                      Using the ball end of a wiggler in a similar manner gives similar results. The method of using layout blue would require a deft touch I am sure, but would give very good results.
                      Another method involves using a wiggler, dowel pin or similar item with a precise diameter and cigarette paper. Stick the paper to the work, and bring the indicator in until the paper is whisked away, you are now 0.001" from edge.
                      Jim H.


                      • #12

                        Same reason I drifted back to making tea with loose tea leaves and not tea bags!! Same reason I went back to a 'nipple' mouse on my laptop instead of the 'finger board' type mouse. Suppose I'm an Old Codger in reality!!

                        The electronic edge finder, I must admit, I always use for lining up the vice to the table ways; but for hole centering, and component edge finding I always use the wiggler again. Even if the machine spindle is 'off' it will represent the true edge relationship - whereas the electronic edge finder being used in a 'non running' fashion means the spindle error is not compensated for. The EEF I have is a 'BORITE - Machinist's Mate' and at the time I suspected the tip to have a run out - whether this got a knock or was made out of line like this I don't know. We bought 3 through work and checked them for run out, sent 2 back as being out. Even though I know the tip is reasonably true (0.001" TIR) it's the possible machine spindle error that convinces me the wiggler is the best tool.



                        • #13
                          You "milking" that mouse, or what?

                          Does your wife know you are fondling its "nipple" on a day to day basis?

                          My laptop is a 15Lb Maine Coon cat - who by some stange coincidence, also has "nipples". spooky, ain't it?


                          • #14

                            I thought I might get away with a statement like that with you laid low..... Guess I should have known better by now!

                            The thing about the laptop meeces (as Tom would say) is that I had a Panasonic around 1994 with the finger pad - everyone else hated it but I loved it, then I went back to a IBM laptop with a (multicoloured - to your choice!) nipple. Now I can't use the finger pad mouse to save my life! And everyone hates using the nipple mouse. S'funny how tastes change over a few years.

                            Does the Maine Coon Cat know about you referring to her nipples as 'mice'?????

                            BTW - Good to have you back, Me ol' mate



                            • #15
                              Thrud have you ever tried milking a bull they don't half give you a funny look,but strangely don't get angry.So I've been led to believe from medical books you understand.
                              Please excuse my typing as I have a form of parkinsons disease