What is an edge finder and how does it work?

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Seriously.  What is an edge finder, and how does it work?  

 

Re: What is an edge finder and how does it work?
Bob La Londe wrote:

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Google is your friend.

http://www.metalwebnews.com/howto/edge/edgefind.html

Re: What is an edge finder and how does it work?
On a piece to be milled many feature's position is referenced from the edges
of the piece, like bolt holes. By placing the edge finder into the spindle
and advancing the table until contact is made, your DRO can be zeroed. Once
the piece's position is set, the tool of choice can be installed, the table
then moved to the referenced position and the appropriate work performed in
the precisely correct place. This is just one of many similar uses.
Steve

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Re: What is an edge finder and how does it work?
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This topic was practically beaten to death in this forum not very long
ago.  Search for it.  One contributor did sterling work reporting on
the accuracy of his tests, etc.

Wolfgang

Re: What is an edge finder and how does it work?
I'll take a stab at it.

It is a go-no go feeler gauge.

When set up the central core is on a tipsy edge of movement.

So now when it is held a slightest touch will set it off.

One eases up to the edge and it trips.  Now where is the
spindle center.

The edge finder is held in center by the holder.  Mill holders
are best, chuck ok and almost as good if tightened using all
three holes.

The trigger cylinder is say .125" in diameter.  Taking half of this,
we determine where the center really is since we touched the edge.

It is like a balance beam on a knife edge.  Pushed latterly and the
beam 'drops'.

http://en.wikipedia.org/wiki/Wiggler_ (tool)

Martin

Bob La Londe wrote:
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Re: What is an edge finder and how does it work?
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    Actually -- the two I have are 0.500" diameter and 0.200"
diameter, with the latter easier to use with a resettable dial on the
handwheel.  Run to the point where it just trips (or just before it
trips, depending on your need for precision), and then set the dial to
indicate 0.100" (the radius of the finder's tip, and thus how far your
center line is from the edge).

    The 0.500" one is more of a pain, because you have to set the
dial 0.250" off.

    I presume that they are also made in metric units, in which
chase perhaps a 6mm diameter would give you an offset of 3mm.  A 20mm
one would be nice for a dial which read 10mm full turn -- but would be
rather too large for convenience.  A 5mm would leave you working with
half a mm.

    An imperial one would be a real pain to use on a metric machine,
and vice versa.

    Anyone out there have a metric version?  If so, what is its
working diameter?

    Enjoy,
        DoN.

--
    (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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Re: What is an edge finder and how does it work?
Martin sez:
"It is like a balance beam on a knife edge.  Pushed latterly and the
beam 'drops'."

Very nice description, Martin.  Hmmmnnn, never thought about it before but it
makes me wonder;  If a
wiggler used horizontally, as in a lathe, would be less accurate because of the
force of gravity
added to its moment of inertia.

Bob Swinney


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