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Ned Simmons Ned Simmons is offline
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Default Repeatability of Self Centering Vises

On Fri, 18 Dec 2015 13:03:00 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Bob La Londe" fired this volley in
:

Are there any smallish ones (3-4 inches) that do not have mounting
ears? I would much prefer to set it in another vise rather than mount
it on the table.


Bob, the 'accuracy' might not be there, but repeatability will be pretty
good until the screws and nuts wear. It'll probably be within just a few
thousandths, so long as your stock is accurate as to width between the
jaws. The real variability with them comes from non-linearities of cheap
screws. So various stock widths will affect centering, but the same
stock width over and over will repeat well.


The repeatability will depend to a large degree on the design of the
screw's thrust bearing. In a normal vise the play in the thrust
bearing is taken up when the vise is clamped, not so with a centering
vise.

If the thrust bearing is adjustable, as in a Kurt, there should be
minimal play and good repeatability.

The only way to take the free play out of these vises from Grizzly is
by shimming the screw.
http://www.grizzly.com/products/Prec...ing-Vise/H7576

I've purchased these on a couple occasions over the last couple years
and the quality is a crap shoot. Several have been quite good right
out of the box, others required some attention to make them barely
usable. We make custom jaws to use them as work supports to hold long
workpieces of varying diameter at a fixed center height - think
adjustable v-blocks.


As to ears... hey... you've got a mill! (Where'd those ears go? G)


The ears disappear off those Grizzly vises in a twinkling.


--
Ned Simmons