On Mon, 14 Feb 2005 16:56:15 -0600, Don Foreman
wrote:

On 14 Feb 2005 00:27:01 -0800, "Jake" wrote:

I'm posting this to this group because it seems that this is where most
of the hydraulics related questions go.

You need to define what you want your project to do before you decide
(or ask others) how to do it. You need to know what forces, speeds,
and precisions it should have, and what budget and capabilities you
have or can obtain or develop.

Example: hydraulics are good where force and motion is needed from a
relatively small actuator but nowhere is it written in stone that
they must run at 3000 PSI, use oil, or even be made of metal. Nearly
all industrial hydraulics do use metal, oil and high pressure to get
the very high forces usually associated with hydraulics, but you may
not need your "hand" to be able to crush rocks. If ounces of force
would suffice, then small electric motors and leadscrews might work
well.

I've seen all-plastic hydraulic devices that were all plastic and
used water as fluid: remote throttle actuators in a dynomometer cell
where the operator simply wanted to be outside the region of loud
noise.


Somewhere I have a letter from the DOE/NIST stating that water
pressure can not work for hydraulic devices. And furthermore if water
pressure is lost the solar device will burn down cause the sun will
still be tracked.