Most of the parts I make are small to tiny and fit nicely into my small
Eron milling vise.  Nevertheless, the odd part will come along that
won't and I really hate to remove the vise in order to table mount the
part, then have to spend time reinstalling and tramming the vise again.

So I built a small, auxiliary milling table that looks like this.

The table is 1/2" thick aluminum and the bottom is fitted with a
machined block that can be grasped in the milling vise.