"Leo Lichtman" wrote in message
...

"George" wrote: Is there an optimum size for each jaw set, Leo? Most
agree
there is. So are you advocating less than optimum, or an infinite number
of
jaws?
^^^^^^^^^^^^^^^
The only "optimum" I know is that for jaws with a quarter-circle shape,
they
should ideally grip a spigot that they fit, ie, same radius. One-way
overcomes that restriction by creating a wavy shaped jaw, so that at all
radii, there are two contacts for each jaw, for a total of eight around
the
circle. This, combined with their ribbed design results in excellent
holding power, regardless of how much the jaws have to be opened or closed
to fit the spigot.

With the sophistication of that design, it is surprising to me that they
have sets of jaws with gaps in the coverage.

George, if you can explain to me what you mean by an "optimum" size, I
will
be grateful.



Optimum size is that which puts the greatest amount of metal against wood
without distorting the latter. The quarter-circle types have an optimum size
of circularity plus or minus perhaps 5%. I call this the optimum situation,
because any deformation makes realignment after a dismount more difficult.
The status quo ante just no longer exists. The weakness of the Oneway
design is that it has to "grip" by distorting or destroying the integrity of
the portion gripped.

Thus my preference for non-destructive mounting using dovetails to shoulder
either in recess or against an external shoulder. It makes circularity a
cinch, because the wedge centers as it draws the piece back into the chuck,
where the shoulder or recess now resists angular forces. Optimum size is
slightly less critical here, because it is easier to ensure registry against
its shoulders or interior recess. It does not have to grip nor distort that
which it holds.

If you really want to improve a ridged external hold, you would do well to
consider asymmetrical ridges, with the flat toward the piece, and the wedge
toward the chuck. That way they would automatically push against the fibers
engaged, snugging the chuck against a shoulder as mini wedges or dovetails.
You still would want to have minimum disturbance in the fiber structure,
therefore an optimum size would exist, but at least you would not have a
situation where symmetrical ridges are as likely to push away from
shouldering as toward.