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.
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
The edge finder is held in center by the holder. Mill holders
are best, chuck ok and almost as good if tightened using all
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
Bob La Londe wrote:
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
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"It is like a balance beam on a knife edge. Pushed latterly and the
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.
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