[wms]

Ken,
It depends on how small the parts are.
The magnetic chuck thing will work for some things depending on the chuck's pull, (some of the new ones are quite impressive) and of course the part would have to be magnitic. Although I have seen guys use metal strips to fence in non magnetic parts. But the force to hold these was light, so the cuts were also light.

A common way to hold small parts is to machine soft vice jaws that the part, after it has been machined to a certain point, can then be inserted into. By this I mean that the outside profile or some other feature, say a bore, is machined in the jaws, a mirror image, that is. Then the 1/2 done part is "flipped over and the jaws close down on the part line and hold the part while you finish machining it.

Normally the material cost are so small that it is better to use material that allows you to have .125 or .250 left at the bottom of the part to hold on to it in a set of step jaws. Then you can machine all the way down the part then flip it over in the soft jaws and machine the extra off and finish your part.

As you can see in the photo of your part, you would start with material that is .250 thicker than your part. Then you would machine it down to the orange layer, which is the real bottom of your model. Then you would flip it over into the soft jaws that would be a mirror image of your part, the green layer, and the jaw line would be split along the center of your model, and slightly less deep than your model. Then you would remove the extra material.