Edge finding that does not mare the work. - Page 2
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  1. #21
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    Marring the work with and edge finder may be a matter of what the work finish is and how soft it is.
    If I had to finish the back end of a small mirror mount with the mirror attached so as to hold back length I would not hit the mirror with an edge finder.
    Normally of no concern but I'd bet that if you get your 1500X microsope out all rotating edge finders marr the work piece in conventional materials.
    If you have one micron readouts every notice that such edge finders "snap" in just a bit from hit one to hit two? Second a tad more and then three,four and they settle down.
    Bob

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    I've been using a Starrett edge finder for over 45 years and I've never seen one dent the edge unless I've crashed in one. I have a 3D tester but find the edge finder better suited and easier to use mostly because I don't like dials with .001 resolution. You have to be looking straight on to get the best reading. With an edge finder it doesn't matter where you your standing. I find that I can repeat to within .0002 with the edge finder in the CNC and with a manual machine .0005 is about the best you can expect. A $300 3D tester would be a waste of money on a manual machine.

  3. #23
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    Quote Originally Posted by CarbideBob View Post
    Marring the work with and edge finder may be a matter of what the work finish is and how soft it is.
    If I had to finish the back end of a small mirror mount with the mirror attached so as to hold back length I would not hit the mirror with an edge finder.
    Normally of no concern but I'd bet that if you get your 1500X microsope out all rotating edge finders marr the work piece in conventional materials.
    If you have one micron readouts every notice that such edge finders "snap" in just a bit from hit one to hit two? Second a tad more and then three,four and they settle down.
    Bob
    If it takes 1500 magnification to see it, then I would think it could be easily buffed out with a cotton rag. With my 4 mag old man's glasses I could not tell you where the finder touched just from looking, even on soft delrin.

  4. #24
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    I'm inclined to think that Edge finder sucks. Even in the video on the page he linked it did leave a small mark on the part. I've got an old 1/2" Brown and Sharpe someone gave to me and I can't say I've ever noticed anything left behind.

  5. #25
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    I keep a pack of Zig Zags on the mill ram. a paper placed between the work (lick it and stick it) and anything in the quill will pull away when the paper is pressed. Call it, .001- .0015". (mic the paper if you want.)

    No contact,,, works every time, no fancy optics needed...

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  7. #26
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    Today I put my edge finder on the top tray of my tool cabinet. I then I said to it that you are a piece of shit and I'm not using you. Instead you can watch me
    sight in the center postion for some holes.

    Brushed some blue and a scribed a few lines. Then I cut a point on a 3/8" bar and chucked it. Used a 10x eye piece and centered the point of the bar.
    Hole position was .001 off. So for a hole that has some slop for a screw the position is good.

    I use a caliper with the distance set to slightly less than half distance across the piece. The mark a line from each side. Then I just dial in between the lines.
    It works pretty good. As I tap the handle for position I know the movements are in less than .001 increments.

    Then I looked at the edge finder and said "you can drink paddy water now".
    Last edited by rons; 09-14-2020 at 01:43 AM.

  8. #27
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    I'm still rather amused at this conversation...

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  10. #28
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    Uh, if your bar is a known, consistent width, why are you not just edge finding the fixed jaw of the vise and moving over half your known width?

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  12. #29
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    And, aside from cheapo eccentric edge-finders that won't work, a microscopic nick or any abrasive on the sliding edges/faces will make it inoperable and/or unreliable. If the faces get scratched, might as well trash them. I also use them frequently for centering holes on round features/stock using the DRO, if the accuracy of indicating the hole isn't required: eyeball center and pickup one side of feature with ef, zero DRO, pickup other side with ef, divide by two to get center, repeat for other axis. Good for .0005"-.001.

  13. #30
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    The electronic edge finders are great but are only made with .500 shanks. Often you want to use one with different size collets and I've been toying with the idea of making ones with ceramic spacers as centers and then grinding the ends to final size. They could then be used with any continuity tester. There are circuits posted on the internet that measure the resistance through the spindle etc. all the way back to the work holder but they are finicky to adjust and not all that convenient.

    Quote Originally Posted by CalG View Post
    I keep a pack of Zig Zags on the mill ram. a paper placed between the work (lick it and stick it) and anything in the quill will pull away when the paper is pressed. Call it, .001- .0015". (mic the paper if you want.)

    No contact,,, works every time, no fancy optics needed...
    I was shown that trick many years ago and it does get you within a thou or so. For the uninformed, Zig Zags are a brand of cigarette paper used to "roll your own" (filling choice optional).

  14. #31
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    The non rotating electronic edge finders are only accurate if the contact is on the same spot, or mark your device so the work contact is on the same spot on the probe.

  15. #32
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    As others have said, it should not leave a mark. Something is wrong. Regardless, if you can’t sort that out:

    1. Interpose something sacrificial like zig zag paper or even thinner, bluing.
    2. Indicate off the vise jaw, going the other direction.
    3. Add a shim of a known dimension (like a .100 block), indicate off that, then subtract the known dimension.

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  17. #33
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    Pros would go for the electronic probe, but reasonable results can be had the old way.

  18. #34
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    A toolmaker would just hang an Indicol on the chuck and tram it in with a test indicator. Then you know you on center.
    Dennis

  19. #35
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    Yes indicating a part in is tried and true.

  20. #36
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    Quote Originally Posted by DanielG View Post
    The Haimer Zero Master model is 10mm shank and <4" long, so if you're running a 1/2" drill chuck it should fit.
    I've never used one, so ..? Don't they have to be indicated in to be accurate?

  21. #37
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    "Don't they have to be indicated in to be accurate?"

    I think so, I test the part on the high point of the probes run-out, found with an indicator "Accurite probe"

  22. #38
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    Quote Originally Posted by Mike1974 View Post
    I've never used one, so ..? Don't they have to be indicated in to be accurate?
    Yes, you need to get the ball runout as small as practical. If the ball is offset, then so is the location of zero. Setting and periodically checking the runout is the major use for my tenths indicator. The runout typically stays small, but a hard bump could upset it. You don't want to run off a big batch of bad parts because your Haimer developed runout and you didn't know it.


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