Interestingly they avocate climb milling over normal milling, where the machine is capable of this, as the forces tend to press the work down onto the chuck.

In general the use of stops and jigs is advocated to ensure work cannot easily be dislodged. Take note that when it is desired to mill around the edges of a component (i.e. it has no stops in place) they suggest it should have minimum dimensions of 300mm by 300mm...

The long and short of it appears to be that magnetic chucks can be used to hold workl for milling and turning, but considerable care should be taken to follow the guidelines given by the chuck manufacturer.

eclipse magnetic chuck handbook.pdf

eclipse power matrix chuck manual.pdf

Thanks to Eclipse for supplying these manuals to us.