Hi all,

I have this model which is an extreme simplification of a press.

I've atatched the model to this forum thread.

The two colums are threaded, and there are four nuts fastening them.

If you apply esternal load this is the deformed shape you'll get:

The press works in a way that load is cyclical (up and down movement), and I don't want my threaded colums to be subject to fatigue.

I want to therefore preload them.

My questions are:

- what would be the best way to create a pre-load ?

- Would a preload that equals the external load be enough to prevent the threaded colums from being subject to fatigue ?

Thanks,

Alex