0NachoMahma 12 years ago . Speaker coils (bass drivers will have larger wire). Solenoids. Relays. Transformers ('though these can be difficult to separate from the core). . One way to wind coils that has worked well for me is to chuck up a bobbin in a variable speed drill. Run the drill at slow speed (a foot-operated speed control would be great) and feed the wire onto the bobbin.