The easiest way is to start unwrapping the pickup turn by turn and counting the number of turns per layer. I would go down a layer or two before you seriously start counting each turn per layer. As you unwrap you will soon begin to see a pattern of how the wire was put on.

To start, let’s say the bottom edge of the bobbin is where the eyelet would be in a Fender style pickup. The top edge is the closest part of the bobbin that is nearest the strings. On humbucking pickups the bottom is where the mounting screws are fastened to the bottom of the bobbin. The top is again the area nearest the strings. Pickups are usually put on the winding machine with the top of the bobbin Facing Left or Facing Right. The coil can be rotated either Top Coming or Top Going As you unwrap the coil make notes on the relationship between the layers and number of turns per layer.

As you count the number of turns per layer and each layer has the same average number of turns, you can be pretty much assured the bobbin was automatically machine wound. When unwinding you see that one layer has 46 turns and the next has 58 and so on, you can usually assume that it was scatter wound or hand wound. I like hand winding better because you can control the tension as you like it. With automatic coil machine winding you can’t tell or feel the amount of tension that is on a paticular pickup. You can use magnet wire tension gauges but they can be quite expensive. I keep books of information and it helps for future research.