Magnets & Copper Wire: A Pickup Building Thread

[Bruce Johnson]

I feel like this may be one of those questions that's either very thought evoking, or really stupid. But: should we expect a difference? Does "humbucking" in and of itself change the tone of a pickup?

When comparing a typical single coil to a typical humbucker (say, a tele pickup to a PAF style humbucker, or a Jazz bass pickup to a typical two-coil soapbar humbucker), my impression was that the difference in tone was more from the difference in sensing width along the string and coil shape, rather than just the fact that it's a humbucker. With that in mind, my thought for this electromagnet pickup was a typical two coil side by side arrangement where each coil senses the whole string and you could turn off one coil completely (the coil and the magnet).

I have made lots of plain old single coil Jazz pickups, and several split coil pickups that are essentially the exact same construction, just with the flatwork cut in half so you can wind two coils instead of one. This strikes me as more or less equivalent to your idea. I've never directly A/B'd them but I guess my question is, SHOULD there be a difference?

But I'm also starting to wonder if this would all be worthwhile at all or if there are better ways to get there. Besides the sensing width in terms of the magnet, I'm really starting to become more of a firm believer that the size and shape of the coil is important. I've recently built a new ukulele pickup that's a straightforward two-coil blade humbucker. I've made other uke humbuckes, typically as miniature versions of a guitar PAF humbucker, and they sound like you'd expect them to - like a Les Paul or other Gibson. Meanwhile, this new pickup is pretty different. The two coils are very thin (wrapped on 1/16" steel blades) and very tall (a hair more than 5/8") as compared to a PAF. The pickup sounds totally different, despite having the same magnet and the same number of turns as the PAF style pickups. If you close your eyes, you'd swear it was a twangy single coil telecaster pickup. It just sounds like a narrow single coil pickup despite being a humbucker. I've also recently built a Jazz pickup that's as short and fat as I could fit in the shell. Same number of turns and same magnets as other J's I've built, but it has a pretty different tone. Next up I'm going to try the opposite on a P pickup - make a skinny tall coil, and see if I can get something different than the typical P - my goal is to imitate the brighter, more balanced tone of an underwound P, but without the potential loss of output level. If that works (and I'm confident it will), I want to put two skinny tall coils in each P shell, and then set them up so it can be "coil tapped" by turning two of the four off. I figure that'll give the most versatility possible in a P format.

Yeah, I completely agree. When most folks compare Single Coil and Humbucker pickup sounds, they really mean Fender Jazz vs Fender P-Bass. But the Fender Jazz and Fender P-Bass pickups are very different in their internal geometry, in ways that significantly change their sound. They are two different pickups, regardless of whether they are single coil or humbucker.

You can build a split-coil humbucking pickup with Jazz coil geometry, and it won't sound that much different from a single-coil Jazz. Likewise, a single-coil with a short wide P-Bass style bobbin will sound more like a P-Bass than a Jazz.

The geometry of the coil, and how it fits within the magnetic field, is more important to the overall sound of the pickup than is the choice of single coil vs split humbucker.

 

[slowburnaz]

I've been playing around with a more vintage-y look for a single coil design:

Now I get to play around with different winds to see what works best.

 

[Bruce Johnson]

I've been playing around with a more vintage-y look for a single coil design:
View attachment 4267391 View attachment 4267392View attachment 4267390 View attachment 4267393

Now I get to play around with different winds to see what works best.

I like it! I assume that the cover is 3D printed?

Now Jeremy (aka Freekmagnet) is going to want his own 3D printer!

 

[dwizum]

That is crazy! We need details on how you did it.

 

[RichterScale]

Could you imagine a bunch of folks on here collaborating to build a few lines of guitars/basses?

 

[Freekmagnet]

I like it! I assume that the cover is 3D printed?

Now Jeremy (aka Freekmagnet) is going to want his own 3D printer!

Haha - I don’t have any plans for a 3D as of yet. I’m more inclined to get some kind of a cutter. I’m not sure what kind of cutter yet. (laser, water jet, small CNC router, etc)

That being said, cutters and printers seem to go hand in hand.

 

[dwizum]

Haha - I don’t have any plans for a 3D as of yet. I’m more inclined to get some kind of a cutter. I’m not sure what kind of cutter yet. (laser, water jet, small CNC router, etc)

That being said, cutters and printers seem to go hand in hand.

I'm in pretty much the same boat. I'd really like something for making complicated jobs like that easier, but I don't really think I want a printer, so I've oscillated between a laser cutter or a small CNC router or mill. I can't really justify either one just for pickup making, so I think I'd lean slightly towards a CNC router/mill since that could theoretically be used for other hardware and small wood parts too.

 

[Freekmagnet]

I'm in pretty much the same boat. I'd really like something for making complicated jobs like that easier, but I don't really think I want a printer, so I've oscillated between a laser cutter or a small CNC router or mill. I can't really justify either one just for pickup making, so I think I'd lean slightly towards a CNC router/mill since that could theoretically be used for other hardware and small wood parts too.

Yeah, an architect friend of mine who used to run a small CNC shop recommended a Wazer. The Wazer is a bench top water-jet cutter. Apparently, they’re good for small metal parts and stuff like that. It probably wouldn’t work to good for wood. They’re pricey, too. They run about $7K.

I could really see a laser cutter being handy for dumb stuff like cutting flatwork, but I can just order it from Ponoko for a couple bucks per piece. I’ve been getting into laser engraving lately, so I could see that being handy. With lasers, it comes down to scale. You need a powerful laser to cut metal, and for guitar stuff, you need a pretty large work area.

CNC routers seem less and less appealing to me. I see guys doing pretty nice guitars with consumer-grade equipment, but at that scale I don’t see that there’s a big enough advantage to using one.

 

[dwizum]

I guess it boils down to the potential overlap and figuring out what capabilities are unique. For me, I don't think I'd ever use a CNC router to cut a typical bass or guitar body, neck, or fretboard. I can push a piece of wood through a bandsaw and then route to a template by hand just fine. But for fiddly little things where it would be complicated to cut by hand, or there isn't a good ponoko equivalent (something like cutting the lattice work in a pickup cover as seen above, or making small aluminum or brass hardware) it seems like there aren't any good at-home options except a CNC router. And then if I had it for those uses I could cut my own flatwork too instead of relying on ponoko or spending a lot of time making the routing jigs like I posted earlier.

 

[slowburnaz]

I like it! I assume that the cover is 3D printed?

Now Jeremy (aka Freekmagnet) is going to want his own 3D printer!

That is crazy! We need details on how you did it.

You're right, Bruce... the cover and bobbin (and the ring, which isn't shown in those pics) are all 3D printed. The top of the bobbin matches the inside dimensions of the cavity of the cover, which allows a little hand cut sheet of brass or stainless mesh to be sandwiched between. Everything is sorta held together by those 4 screws, which pass through the baseplate and mate to some press fit nuts in the cover itself.

When I was designing everything on the computer, I wasn't quite sure how it would all work together. But, thankfully it all works like I wanted.

Now the hard part... getting it to sound like I want.

 

[Freekmagnet]

I guess it boils down to the potential overlap and figuring out what capabilities are unique. For me, I don't think I'd ever use a CNC router to cut a typical bass or guitar body, neck, or fretboard. I can push a piece of wood through a bandsaw and then route to a template by hand just fine. But for fiddly little things where it would be complicated to cut by hand, or there isn't a good ponoko equivalent (something like cutting the lattice work in a pickup cover as seen above, or making small aluminum or brass hardware) it seems like there aren't any good at-home options except a CNC router. And then if I had it for those uses I could cut my own flatwork too instead of relying on ponoko or spending a lot of time making the routing jigs like I posted earlier.

Yeah, that’s kind of a gotcha right there; I’m not sure how well suited the CNC router is for cutting those small pieces or fine details in metal or even flatwork. Apparently the smaller machines really struggle with metal pieces.

 

[Jeff Siddall]

Yeah, that’s kind of a gotcha right there; I’m not sure how well suited the CNC router is for cutting those small pieces or fine details in metal or even flatwork. Apparently the smaller machines really struggle with metal pieces.

Yeah, I am not sure about this either. Fiberboard I would expect would be pretty easy for a small CNC but metal is always trickier. Laser cutting fiberboard should also be possible with a small CNC setup, metal, not so much.

I did write a G-code generator to CNC cut wood pickup covers. Sure, you can do those by hand using routing templates etc., but things like milling countersinks for the screw mounts precisely in the center of a corner radius is fiddly to get perfect by hand.

For me a CNC did the most tricky lutherie things. Having a bunch of specialized tools is also good, but I just don't have space or funds for everything.

 

[Bruce Johnson]

Don't forget....Resin casting as a way to make decorative covers like what slowburnaz made. With resin casting you only have to make the Master one time, and the Master can be made from soft plastic, wood, wax or clay. Once you've hand carved (or carved with a mini CNC, or paid someone else to 3D print) the Master, you make a mold from it. Then all the actual pickup covers are cast in the molds from polyurethane resin. That's faster and less labor per part than 3D printing every cover.

 

[Novarocker]

I guess it boils down to the potential overlap and figuring out what capabilities are unique. For me, I don't think I'd ever use a CNC router to cut a typical bass or guitar body, neck, or fretboard. I can push a piece of wood through a bandsaw and then route to a template by hand just fine. But for fiddly little things where it would be complicated to cut by hand, or there isn't a good ponoko equivalent (something like cutting the lattice work in a pickup cover as seen above, or making small aluminum or brass hardware) it seems like there aren't any good at-home options except a CNC router. And then if I had it for those uses I could cut my own flatwork too instead of relying on ponoko or spending a lot of time making the routing jigs like I posted earlier.

That's exactly why I'm moving towards the CNC route myself. Not perfect, but sufficient for the covering the most ground effectively.

 

[Bruce Johnson]

Yeah, if/when I ever move into computer-driven machinery, the first thing I want is a small CNC milling machine. Capable of precision machining relatively small metal parts. I wouldn't use it for making many production metal parts or pickup parts. Its main use would be making up tooling; precise complex Masters, which I would then make molds from.

 

[Freekmagnet]

This guy did a pretty good review of the OpenBuilds Mini-mill and the modifications he did to make it a more robust and useable machine.

I was eyeing this machine for a while, but the amount of work the reviewer did to it made my eyes glaze over. Other than that, it’s compact, affordable, and with some work, it looks like you can do some real stuff with it.

Haha - I dunno @Bruce Johnson, maybe that front room might make a good mini-CNC lab…

 

[Bruce Johnson]

This guy did a pretty good review of the OpenBuilds Mini-mill and the modifications he did to make it a more robust and useable machine.

I was eyeing this machine for a while, but the amount of work the reviewer did to it made my eyes glaze over. Other than that, it’s compact, affordable, and with some work, it looks like you can do some real stuff with it.

Haha - I dunno @Bruce Johnson, maybe that front room might make a good mini-CNC lab…

If you want to get a machine like that, and learn how to use it, I'd be happy to find a space for it here in my shop. I could help you machining up any parts it needs. And, when you get it going, I'd pay you to make up parts for me.

As a CNC mill, to me that's in the Toy category. But it could be very useful for pickup parts. Like making Masters for casting housings and bobbins. Or fancy decorative name plates for instruments.

I also have a small CNC engraving machine that I bought from a friend 15 years ago. As far as I know, it's in good running condition. It was made in the mid-1990's. I even have the original software for Win 95. It needs someone who understands computers better than I do to get it running on some more modern computer. It was made for cutting circuit boards and doing light engraving. Maybe it can cut Forbon for you?

I'd be glad to set it up over in Unit 2, if you want to play around with it and get it running. If you can get it to engrave nameplates, I'll pay you to make them up for me.

I love the idea of building up a mini-CNC lab here.

 

[Freekmagnet]

I love the idea of building up a mini-CNC lab here.

Yeah, maybe at some point down the road for sure. I've kind of got a few things I want to get cleared off of my plate in the immediate future. Setting something like that up and learning how to use it is a lot of work, but I could see doing it. I do really like the idea of having a little workshop dedicated to making really small parts.

A lot of that new desktop CNC stuff is getting pretty affordable and it's getting easier and easier to use. Most of these products would fall into what you refer to as the "toy" category, but for making pickup parts, they would probably do the job just fine. We're not trying to send a man to the moon or anything.

I don't really know enough about the software that runs these machines well enough to say if that engraver of yours will still work. You might be able to put Windows 95 on to an old computer or something and have it dedicated to that engraver. Just don't hook it up to the network. Or it may be a thing where if the mechanics are still good, you can replace the brains with something newer. But like I said, I don't know a ton about this stuff.

I'll start thinking about this CNC lab thing. I might have a couple of feelers I could send out on some used gear.

 

[slowburnaz]

Don't forget....Resin casting as a way to make decorative covers like what slowburnaz made. With resin casting you only have to make the Master one time, and the Master can be made from soft plastic, wood, wax or clay. Once you've hand carved (or carved with a mini CNC, or paid someone else to 3D print) the Master, you make a mold from it. Then all the actual pickup covers are cast in the molds from polyurethane resin. That's faster and less labor per part than 3D printing every cover.

Hey Bruce,

For resin casting, have you had success making clean casts of things with holes through them? By that, I mean, like a pickup cover that has holes for rod magnets, or pole screws, etc.

I tried some time back with a basic Musicman style cover master, and I always had this thin film of resin (flashing?) covering the holes in the casting, which then had to be cut away.

 

[Bruce Johnson]

Hey Bruce,

For resin casting, have you had success making clean casts of things with holes through them? By that, I mean, like a pickup cover that has holes for rod magnets, or pole screws, etc.

I tried some time back with a basic Musicman style cover master, and I always had this thin film of resin (flashing?) covering the holes in the casting, which then had to be cut away.

Yes, I frequently cast holes into my parts. If you are getting flashing at the bottom of the holes, it means that the male plug on one side of your mold isn't extending far enough into the other side of the mold. You need to make the molds so that plugs extend from one half of the mold over into sockets in the other half. For round holes like screws and pole pieces, you can use steel dowel pins.

Assuming that you are using a two-part mold, casting a pickup shell. And you are working from an existing shell that you made by 3D printing. When you are setting up to pour the first half of the mold, attach some steel dowel pins in the holes of the existing shell. For example, if you are making 1/4" holes for 1/4" pole pieces, use 1/4" x 1" steel dowel pins. Lightly glue them into the existing shell so they are sticking straight up and most of the length is above the shell. Leave maybe 1/4" of the pins sticking inside the shell. Pour the outer mold, with the pins in the shell. Then flip it over and pour the inner mold, with the shell and the pins in there.

When you take the molds apart, there will be matching holes in the two mold halves. They will be 3/4" deep in the outer half and 1/4" deep in the inner half. Now, plug a set of the pins into the outer half of the mold. They stay in there and become part of the mold when you pour the resin for the part. When you separate the mold halves, sometimes the pins will stay stuck in the part. No big deal. Give them a slight twist with pliers to crack the bond loose, pull them out of the part, and plug them back into the outer mold for the next casting.

You can also get fancier with the pins. Here, I'm casting black epoxy around the outside of these pickup coils, face down, in single sided molds. I've machined up steel pins with shoulders to make counterbored holes in the epoxy for the adjusting screws. I've made the pins extend up through the bottom of a wood frame holding the silicone molds, to make sure they stay accurately aligned during the casting. I've made T-handles on the bottoms of them, so I can crack them loose and pull them out after the epoxy has cured.