Do any of these ACTUALLY lock DOWN? The way I understand it is there is
a tapered dog on the screw that engages a tapered slot on the moveable
vise jaw (often with moving hemispheres to unify forces). This causes
tightening of the vise jaw to pull down as well as forward. For the
sake of this conversation forward is toward the fixed jaw regardless of
the orientation of the vise itself.

Just about everybody says the moveable jaw will still lift up and you
have to tap down your part with some form of knocker. I have several
"lock down" vises. Well at least 8 or 9. None are high end Kurt,
Orange, Glacern etc... Shar's, Enco, Noname are those I have. For the
most part this seems to be true with my Shar's 8" vises probably having
the least amount of lift followed closely by my 2 of my 4 noname "CNC"
lock down mill vises.

With that in mind I have two questions?

1. Do the top brand name vises have less to effectively zero jaw lift?
2. If using machined soft jaws won't that cause your part to lift in an
incorrectable manner?

(Yes I am aware that if you machined the soft jaws in place with the
jaws clamped on sonething the difference may be cancelled or partially
cancelled. Hence the need for a torque wrench for machining higher
precision parts.)

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