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Wiggler / Center finder? How-what?

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  • Wiggler / Center finder? How-what?

    ......A chance to excell! Obviously I'm new and need clarification. I bought a Starret wiggler and have a nebulous idea of how it's used. Could someone please simply explain how they're used and the reason for their existance? I can fix it in my mind then what it's use is. It has 4 ball socket inserts that I guess do the same thing ...... differently :-)? TIA,

    Son of the silver stream ..... Bullet caster.

  • #2
    All laid out for you here.

    John S.

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


    • #3
      Nice article -- but it does't say what you have found. When it "kicks" have you found the edge relative to the center of the spindle or the edge of the workpiece relative to some other reference such as the diameter of the upper part of the finder? What operations(s) are made easier or possible by the edge finder?


      • #4
        How about this one...............

        or this one......................

        [This message has been edited by G.A. Ewen (edited 02-13-2004).]
        To invent, you need a good imagination - and a pile of junk. Thomas A. Edison


        • #5

          Look at the first sentence in John's link:

          "When the kick is observed, the axis of the spindle and the edge of the workpiece are located 1/2 the diameter of the Edge Finder from each other. This is typically 0.100" (0.200/2 = 0.100") but can be different so check."

          Amplifying a trifle, this 1/2 dia is called the "offset". 0.200 dia edgefinders require 0.100" offset. A wiggler with the 0.100" dia edgefinder attachment (Starrett calls this a "disk contact") requires 0.050" offset.

          The offset can be different. I somehow wound up with an edgefinder .094" in dia. I've grabbed it several times by accident and mis-located edges by 0.003" iside the work. No, I dunno. Don't ask be why I haven't thrown this treasonous POS as far as I can into the bushes.

          Moving on to the topic question, the wiggler center finder is a handy way to visualize the spindle center line.

          The wigggler is chucked in the drill press or the mill spindle and setto rotating 500 to 1000 RPM.

          Using a 6" scale, the center finder point is "pried" over where it runs true.

          Then the centerfinder point is poised just above the work and layout for the hole to be drill positioned under the point. A good hand eye with a keen eye and sharp mental perceptions can locate holes within 0.005 TIR of an accurate layout using a wiggler.

          Of the four commonly supplied attachments in a wiggler kit (the center finder, the edge finder, the ball contact, and the indicator attachment. I've never used the last two in 40 years.

          The wiggler has a "firm" ball and socket joint intended to be moved while spinning. The ball contact is simply too clumsy and the indicator attachment doesn't seat firm enough in the ball joint to take reliable readings.

          If you have a choice get a wiggler having only the center finder (the pointy thing) and the edge finder (the mushroom head thing).

          [This message has been edited by Forrest Addy (edited 02-13-2004).]


          • #6
            Has anyone used a "pump center" to center work in the lathe? As I understand this device, it is a ground two piece rod assemble with one end sliding within the end of the other with a spring inside pushing the two apart axially. One end has a 60deg center hole and is placed against the tailstock center. The other end has a 60deg point and is place in a center punched hole in the work. An indicator is placed on the punch near the work. The work is centered as usual with an indicator.

            I don't have one, or have used one, but I'm interested if others have?


            • #7
              Canonicalman, I made my own pump center and use it each and ever time I place work with a "dot" punched in it in the 4-jaw or faceplate. I used a relatively weak spring so that the pump center won't push the work deeper into the 4-jaw than necessary. It works very well - I'm usually able to get the work centered well enough that there's no movement on the indicator needle.


              • #8
                .........Thank you for the addresses, and thanks to Forrest Addy for taking the time to write it out. As I mentioned I'm new to almost all of this and some of these things are a bit mysterious.

                Son of the silver stream ..... Bullet caster.