On Sun, 17 Jul 2011 04:43:07 -0700 (PDT), Jim Wilkins
wrote:

On Jul 16, 11:18*pm, wrote:
...
I think up to ~80% of the tightening force on a screw can be lost to
friction. Compare the torque to tighten with that to loosen.

I guess they are different :-) ??
...
Michael Koblic,
Campbell River, BC-

Not by much sometimes. AFAIK the torque to loosen is mainly from
friction. In a simple system like sliding a load up a ramp the force
going up is the friction + the load, going down it's the friction -
the load.

My 10,000 # load cell is a pressure gage on a cylinder like this:
http://www.harborfreight.com/10-ton-...ram-95979.html

I had to go to YouTube to see what this does. Is there much call for
moving 10-ton objects 11 mm? However, I can see the use to measure the
load exerted. Do you have a special pressure gauge filled with liquid?

You might find a spring scale for weighing fish/deer/moose in a
sporting goods store.
http://www.harborfreight.com/hand-he...ale-97227.html

Oddly enough that was the only bright idea I had myself. It may be the
only practical one, too :-)

Actually, maybe not. Don N gave me another idea: Rather than
strengthening the bar that holds the screw use the same one and
measure its deflection by a dial indicator.

Michael Koblic,
Campbell River, BC