My First Homemade Pickup
By John Fisher
With the frustration of trying to fix a broken "Demarzio Super Distortion" humbucking pickup my final attempt was to no avail. The very fine wire of the coil had broken off that goes down deep to the center where the core is. What can I do?
I want to say at this point that it is my philosophy that whenever there is an apparent setback or supposed defeat in life, I believe that such defeats can always be turned into new learning experiences and new challenges. For example: not having much money at times has forced me to be more innovative. I look at such handicaps or even different problems in life as the hand of God where life's struggles help us to grow and learn in new ways.
Knowing nothing about the details of such a pickup the scary thought of rewinding it seemed out of the question and my conclusion was just to buy another one. A second scary thought entered my mind," where can I get a good pickup as any thing half decent is very hard to come by here in Peru? " not to mention the money which I don't have at the moment. I then came to the second conclusion of maybe taking a another look at the possibility of rewinding the old one. I began researching this possibility.
The only wire I could find at the time was some #41 gauge wire. I thought this shouldn't be so different from #42 but I then realized that there was a significant difference even in just one number. I think too that this particular coil had #43 which is even finer wire.
So I did an experiment and tried the #41 wire anyway. I didn't know what to do to rewind it but I got a multi-speed drill and put a step down transformer on it to try and make it go even slower. I mounted a screw in a block of wood so that I could screw the pickup bobbin onto the wood block and the screw would then fit in the chuck of the drill. I very crudely clamped the drill to a table. I then made another axle for the bolt of wire to be mounted so it could spin around while winding the coil. Since this was an experiment and I had no idea how many turns or anything, I just filled up the bobbin with as much wire as I could. Although a little sloppy, it still went fairly quickly.
Here is my first crude attempt to rewind the coil. I clamped the drill to the table using a piece of carpet and a couple of drywall screws. I pressed the trigger on the drill with one hand as I guided the wire that was feeding the bobbin with the other hand. If I accelerated too abruptly the wire would break. Remember this is just an experiment but it was a good quick way to get the feel of what I was up against.
When I measured the DC resistance of the coil it was only about 2K ohms as opposed the other existing coil which was about 6K ohms. I then re-assembled the pickup and although it worked, there was not much difference when used in the double coil humbucking configuration or single coil mode as the 2 resistance were so different that one just overpowered the other one. It definitely was not the same as the original pickup. At this point I was just about ready to go back to the "just buy a new one" idea. While viewing some posts about winding pickups at the "Ampage" site, Mark (MKB) suggested that I can just make new bobbins. That way I can be freer to put more windings on the re designed bobbins if desired. With that thought, a light went off in my head and I thought I can just practically make a whole new pickup by making 2 new bobbins and winding 2 new coils. Mark made his bobbins out of some Bakelite sheets and made the core out of some oak hardwood.
I was looking around for some kind of plastic to make the sides of the bobbins and I got the idea to use pieces of an old CD case. The black matte plastic is actually sort of decorative and it certainly is a ready available cheap material. Later I thought you could even use the plastic off an old floppy disk for the same function.
Here is the core that I made out of hardwood for the bobbin. The plastic sides will be glued on to the edges. I drilled holes spaced 1 centimeter apart for the pole pieces. It was more difficult than I thought to do this as I wanted to make the wooden core as narrow as possible so that the coil windings would be as close as possible to the pole pieces. It was very easy for the wood to split. I could have drilled the holes in the wood after I glued the plastic sides on but I though that this way I had less of a chance of making a mistake while drilling the holes. I didn't have the use of a drill press, which would have been better so that made it even more tedious.
Here I glued the wood core to one of the plastic sides. I glued it with acetone based household glue. I think they call it Duco in the US. The glue seems to work very well as it eats slightly into the cheap plastic. You can see in the picture the problem I was having with the wood splitting. I was able to easily repair this with a bit of epoxy glue and then sanding it smooth. I later found that if I make the wood piece for the core temporarily bigger I can drill the holes first without any splitting then shape the wood to size. I also sanded the plastic on the inside of the bobbin to prevent the wire from snagging on any rough edges when winding the coil. At this point I drilled holes in the plastic side for the pole pieces using the existing holes in the wood for the guides. I then glued the other plastic side on and when the glue was dried, I drilled the holes for the pole pieces through the other plastic side. It is important that everything is nice and square.
Mark Hammer shared a lot of good ideas for winding pickups, especially for the first time enthusiasts or experimentalists. One of the ideas I liked the most was to use a simple hand drill. It's a cheap and easy way to do wind things without having to invest a lot of time and money in an elaborate setup. Especially if you don't plan on making a career out of pickup winding. There are also some other advantages to this method which will be explained below.
Here is the hand drill that I had clamped to the work bench. You can see the wooden block with the screw in the drill chuck. I used 2 screws to fasten the bobbin to the wood. It is important that it is centered properly and that it turns very straight with no wobble or you will have a hard time winding the coil neatly and it will be difficult to wind the coil close to the edges where the plastic sides are.
This time when winding the coil I simply put the spool of wire on the floor directly under the hand drill with one end up. This way the wire just seems to unravel with ease while winding. I guided the wire back and forth with my hand as it was being wound on the bobbin. Using your hand also helps you to manually adjust the tension of the windings which is important. For me, using the hand drill was good in that you can control the tension of the windings better and also you can speed up or slow down at your own pace to avoid mistakes, breaks or finding out later that one of the turn was wound outside the bobbin and then you have the unpleasant task of backtracking several hundred turns. If it is too tight it will somewhat stretch the wire but even more importantly if it is too loose the coil will be prone to microphonics. This is where the loose windings will act like the diaphragm of a microphone and when the guitar volume is turned up loud it will squeak with feedback. (not a desirable sound for any style of music.)
See Part II