On Sunday, August 19, 2012 12:37:17 AM UTC-7, N_Cook wrote:
Is there an online calculator anywhere ? or failing that what sort of "packing factor" for 0.08mm (+/- .005mm ) winding on a relay coil.

If you have a dead unknown coil, easiest is to remove the wire
(unwind some, cut if you have to) and (1) find its gauge with
ohmmeter or microscope-and-ruler, (2) weigh the copper after it's
removed.

Get new wire, same gage and weight, and wind all of it onto the form.