Does anyone have an idea of how much pulling force is required to hold a detail in a 5C
collet?

As soon as it warms up, I'm going to make a drawtube. At the moment, I'm thinking a
thrust bearing and hand wheel is how I will build it.

The right hollow shaft cylinder and a deublin coupler has something going for it too.

Springs might work also, that seems to be how it is normally done commercially.

Thanks,

Wes