Early pickups were single coil and prone to noise from transformers or 60Hz mains power. To reduce this, humbuckers were made using two coils wound in opposing directions. There’s a few different types of magnets. The magnets lay flat and the magnetic flux lines pass up through the screws/poles and induce a magnetic field on the strings. The poles are opposite magnetic poles. The name Humbucker comes from “buck the hum”.
Below you can see the coil’s direction in relation to the magnet. A center tap can also be used to select one coil or another.
Below is how the coils are wound in relation to the magnet.
I purchased some parts online and bought a spool of #43 wire. Using a drill and a bracket I made, I wound the wire onto the bobbin. Using some trial and error, I was able to to wind two coils: 7.4K and 6.5K. I allowed for the greater mismatch to try to give these pickups a distinct sound due to the offset. One other benefit to hand wound pickups is that they inherently sound different due to the random pattern when the wire is laid down. Machines that wind pickups lay the wire down in very uniform patterns.
I used a sheet of paper to better see the wire as it’s wound onto the bobbin. This allows for better control over how the wire builds up.
Potting pickups is the process of of submerging the pickups in wax and allowing the wax to replace all the air inside. This helps reduce feedback and also helps protect the coils from damage. Below is me using a double boiler to melt wax and then submerging the pickups. I used 70% paraffin and 30% bees wax.
After potting, I put a plastic cover on the pickup to protect the coils. The plastic does not interfere with the pickup’s ability to capture the vibrating strings.
Hear these pickups in my Rangemaster demo in this video: