Hi Norman,
Think we’re talking about a test where the wire is bent around a mandrel to see if the insulation splits. If it’s a flat-type wire-cable it will be bent on the flat side (di piatto) and edgeways (di costa).

If it’s a round section wire I think they probably mean bent then straightened out again.

2 (fianco, lato) side; edge: mettere qc. di costa, to place st. edgeways (o edge on); di costa a, next to; side by side to


ASTM B733 is an industrial specification for nickel phosphorus EN, and so let's see what it says, shall we? In paragraph 9.4, it uses the bend test from ASTM B571. "A sample specimen is bent 180 degrees over a mandrel diameter 4X the thickness (10 mm minimum) of the specimen and examined at 4X power magnification for flaking or separation at the interface. Fine cracks in the coating on the tension side of the bend are not an indication of poor adhesion. Insertion of a sharp probe at the interface of the coating and basis metal to determine the adhesion is suggested.
Appropriate test specimens are strips approximately 25 to 50 mm wide, 200 to 300 mm long, and 3 to 6 mm thick."

So if you are using a free bend of your small wire, I've got to agree that it could be too severe, depending on the internal angle. Would bending around a 10 mm diameter mandrel be possible? If practice shows that THAT is too severe, then I'd increase the diameter until I found something that worked. Maybe 6X the diameter, justifiable since the bending of a wire is more severe than of a strip- more shear stress.
http://en.allexperts.com/q/Metallurgy-2280/Bend-Test.htm

http://www.wipo.int/pctdb/en/wo.jsp?IA=US2004022859&DISPLAY=...