Hand Winding: This is also known as "scatter winding", where the pickup wire is wound on the bobbin in a random manor. This is how Fender pickups were wound prior to 1965, since it was a semi-manual operation, using a machine to turn the pickup bobbin, while a worker would guide the wire onto the turning bobbin. In 1965, Fender changed to "machine winding", as it is a completely automated process. Machine winding takes away much of the character of the pickup. A lot of the sound of old Fender pickups is due to the random layering and variable winding tension of the wire, which effects the tone. With machine winding, this is all very sterile and consistent. If you see the chart below, notice how consistent the Strat pickup specs get when machine wound (after 1964). Not much variance from year to year with machine winding.