>...solenoids are almost always strongest at the very end of their travel.
> For a pull solenoid, they are strongest when fully pulled in. For a push
> solenoid, they are strongest when the output pin is fully extended.

Sean is correct.
It seems likely that you are reading th data sheet incorrectly.
Can you provide a link to a copy?

Air gap is a critical factor and this typically increases
exponentially as you move away from full activation.

> Most solenoids are really just designed to hold something in position.

Very much depends on your requirement, but force will indeed usually
be much weaker to much much weaker at full airgap..

> I think you probably want an electric gearmotor with linear output to
> push the hydraulic piston.

This is liable to be a better solution for the application you describe.
Another possibility is to use pneumatic or hydralic activation with
electronic valve control.
Or even, control a pump - trickier.


           Russell
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