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(Glenn Cramond) wrote in message . com...
Jack Erbes wrote in message . ..
On Sun, 27 Jul 2003 16:19:50 GMT, steamer wrote:

--What the heck is this thing measuring anyway?

Thanks for the links they were useful.
The Hounsfield was issued to Australian High Schools and Technical
Colleges in great numbers in the days when governments were prepared
to spend money on education. Most schools still have one but keep it
well hidden (mercury). The most common use of the machine is to plot
stress strain curves of various samples of materials.
The test piece is placed under tension with a manual or motor driven
screw (both available), attached to one end of the test piece (uses
chineese finger trap type clamp). The amount of tension applied
causes the end anchoring the test piece to operate a lever that
compresses a leather bag and forces the mercury from the bag along a
horizontal capilliary tube. The tube runs axially beside a rotating
drum (rotated by the screw). By manually marking the length of the
column of mercury, one can plot a stress strain curve, examine
elasticity, determine UTS, yeild point etc.
Other attachments come with the machine to allow similar compression
and shear tests.

Most school budgets don't allow for upgrading or replacement so we
need to find a DIY method of converting these machines. In a school
of 650 kids I have a total budget of $7,500 PA (all tools materials
consumables etc.)

Really appreciate your efforts to help.
Glenn

Sounds like somebody's overly clever method to replace a spring scale.
If it operates a lever, you could probably calibrate a suitable dial
indicator which should be within your budget or go to resistance-type
strain gauges which probably wouldn't be. The latter are what's used
in industry so would probably more useful to your student body.

Stan