I am trying to determine the reasonable maximum pressure applied by my
Record 53 vises. I don't have easy access to a load cell or a bathroom
scale, so I will have to resort to rough calculations otherwise.
Has anyone ever measured the pressures on a Record 53 vise?
wire it up backwards, so to speak, and use it to stretch fishing lines of
known breaking weight to give clamping force followed by a quick division by
the jaw surface area to give pressure ?
Your will to live will probably break before the final poundage is
Ask the manufacturer?
Why on earth you wanna find a figure for this?
I suspect the "unreasonable" result will be limited by operator strength, NOT
the vice mechanics.
Very little pressure is necessary to extract a confession anyway. Usually
just the threat is enough.. :-)
Squish something in the vise and measure the face to face distance before
and during the squish. Use something that doesn't permanently deform when
you squish it. A chunk of aluminum rod with clean, square ends is probably
good. Or maybe the tension spring from your bandsaw. A chunk of hardwood of
known dimension would also be OK. You can relate the compressive strain to
the applied load.
First, it's not pressure, it's FORCE that the vice applies; the
depends on contact area, which makes it different every time, in
ways that aren't terribly interesting. If you take care not to
use slippery materials for the jaws, the vice can grip adequately
at low force, so consider materials of high friction (MDF with
a coat of primer, or even of dried white glue) for jaw plates, if
the work seems ready to slip.
Second, the torque on the handle determines the force, not any
particular property of the vise (unless you are concerned with
breaking stresses of the vise parts). The force is determined
by an operator pushing that handle, who presumably is feeling
the resistance and getting things "tight enough".
If we ignore friction (don't lube the screw, though, or
the thing might pop loose when you don't want)
force = Torque * 6.28 * pitch-of-screw
That "6.28" is two times pi, and the pitch of my vise screw is
four threads per inch, so a hundred pounds on the six-inch
force = (100 lbs * 6 inch) * 6.28 * 4 per inch = 15 000 lbs
Spread over circa 20 square inches, that's over 700 psi...
but it's still only a third of what softwood should handle without
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