Ukulele humbucker pickup bobins

God bless 3d printing! I have trying to make humbuckers for ukuleles and the lack of parts makes fabrication a pain in the ##^$. I had a group run a 3d printing of a bobbin designed for a blade pole piece. This is a pic of the mock up. It looks from the image that it may need some touch up filing to smooth the edges. As soon as I see it in hand and assuming it isn't too rough for the wire I will order 40 for the ten ukes I have in production. Any would be pickup makers out there that are interested in them let me know and we can combine an order sometime or I will send you the file and you can have them made. At 40 units the come out to $7.5 a piece which is certainly more expensive than buying the guitar ones but after hand making these from wood I feel it would well worth the $15 per pickup.

I was wondering, couldn't you have these cnc'd out of delrin or nylon or uhmw, something like that. Sure would be a lot cheaper and probably cleaner.

This was the wood prototype with 1/8 steel blade fashioned from bar stock available at local hardware store. I couldn't make a bobbin that had a slot for the blade and still be reasonably sized so I made top and bottom pieces than slipped them over the steel. A few wraps of bobbin tape around the steel was needed to keep the wire from breaking as it made the turns. This works but then the only way I could figure to secure it to a bottom plate and keep the whole thing together was to cast them into an epoxy block. Doable but if you ever needed to maintenance the pickup you would be out of luck.

resoman said:

I was wondering, couldn't you have these cnc'd out of delrin or nylon or uhmw, something like that. Sure would be a lot cheaper and probably cleaner.

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Possibly. The people around here that do that kind of thing have such a high set up cost and minimum that it was cost prohibitive. The other reason I asked these guys beside the no minimum is that I could design on sketchup, which I can manage, the CNC guys all want autocad level files which I would have to pay to have done. I am also looking at building or buying a 3d printer for various application so wanted to see what kind of quality I could get. If I like it I will be able to print out custom knobs, pickup covers and mounting rings at very little set up. My luthier work isn't a business right now, I am just playing around with learning different things and trying new designs so I don't want to invest a lot in set up costs on any particular part. This run of ukes is because I had a few people want them after I built one for Victoria Vox so I figured I would build a few extras. Since there is very little out there in the world of pickups for ukuleles I will be trying a lot of different designs before settling down on a couple. At that point it would make much more sense to invest in the setup cost for CNC or even injected molded plastic bobbins.

You guys have set me a conundrum. How do coil pickups work with nylon strings? My basic electricity course, done 45 years ago, would have said you need metal strings to agitate a coil. Is that not the case?

Puzzled of Catalonia

You are right, they don't. You have to use steel strings. Typically 10, 13,21,15 or 17 gauge. It is probably a stretch to call them ukes. They are really more like mini tenor guitars stringed up like a uke so anyone who knows how to play a uke can grab one and join their friends playing rock in a garage band or something. You can pull so many different sounds out of them. Everyone I have put one in their hands can't put them down. They just play around for hours experimenting with all the different things you can do- from total blues/jazz to heavy metal.

I'll make the suggestion that you pattern route them from Garolite XX opaque black material. You can make any bobbin configuration, number of poles, etc. that you wish. Here's a six string hum cancelling single pole as an example:

rudy said:

I'll make the suggestion that you pattern route them from Garolite XX opaque black material. You can make any bobbin configuration, number of poles, etc. that you wish. Here's a six string hum cancelling single pole as an example:

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Very nice. I wouldn't even know where to begin with that. How do you route the area for the windings on such a small object? How long to fabricate the bobbins once you have the pattern made?

Hi Rick,
Pickup construction here more or less follows standard protocol as what anyone else does when doing conventional winding. I see you found your way to the pickup winder's forum; that's a good souce for a lot of useful information although I find many posters there a little too ascerbic for my liking so I don't participate there.

The split single shown is incorporated in my lap steels. I've also wound a bunch of standard single coils in 4, 5, 6, 7, and 8 pole configurations depending on the instrument they are being produced for. The split coil bucker is just a variation of the single coil designs, though.

The coils shown are pattern routed from 1/16" and 1/4" Garolite and joined with the 1/8" Garolite baseplates. It's a simple matter of gang drilling the top and bottom coil plates and pressing in magnets with a temporary wood spacer to hold them at the proper distance apart. It's difficult to explain in a few sentances the entire pickup making procedure. I used 95 photos and accompanying text to describe the pickup construction process in my lap steel construction guide, so you can see there's more to it than meets the eye.

I don't know about the finish on the 3D printed bobbins, but you need them to be both uniform and EXTREMELY SMOOTH to successfully wind. That might prove to be the proverbial fly in the ointment for you.

As far as time goes, if I did only a single pickup it would take about an hour start to finish. The bobbins are only a few minutes of that time if you have the bobbin patterns already done. Obviously the time per pickup goes down if you batch wind several.

I only wind because I'm interested in a particular configuration that's not commercially available at a reasonable price, or special pole numbers or pole spacing considerations. From an economics perspective pickups are available as imports at a price that does not justify your time or materials costs if you can use an off-the-shelf configuration.