Here is an 8 string T-Bucker made in vulcanised fibreboard specifically for an 8 string steel guitar. The staggered coil arrangement eliminates signal cancellation as the flux loops between the inner two poles. Another variation for 8 string steel guitars is this 16 pole humbucker. The casing is machined from Delrin, a fairly expensive acetal based resin that is very durable and can polished to a reasonably high finish (almost Ebony like).
To the left, a Tele bridge pickup with several coil taps. This was made for a customer who wanted to use a rotary selector switch a well as a tone and volume control for some serious tonal variety from a two pickup guitar.
The TP90 to the right was made with the same philosophy in mind. This pickup used ceramic magnets to add a little bite to the tone - the steel baseplate raises the inductance to smooth things out and broaden the magnetic field in much the same way as the magnet layout in a true P90.
To the left is a 7 pole single coil pickup with parallel sides to the base to suit the guitar rout.
A similar approach was taken with this miniature P90 style pickup to the right so that the pickup fitted a minimal rout in the guitar body. On the underside, there are a pair of opposed Neodymium bar magnets with the screw pole interposed. Neodymium is a material that I am finding increasingly useful for developing new pickups and even recreating more traditional tones. It exhibits little of the harshness of ceramic magnets when used with relatively low impedance coils and has a high flux relative to its physical size.
A variation of the P90 formula. Here the magnets are turned edge on and placed either side of the coil, a thin steel shim underneath completes the magnetic circuit. This turned out to be a very nice sounding pickup, the profile is too large for a P90 cover so a Jazzmaster style cover was used instead. To the right, a seven string open coil P90 with the regular twin bar magnet layout under the coil.
Using the exact same Catswhisker replacement parts that I fit to the the Wide Range Humbucker upgrade - the Jazzranger, available with white, aged white and black covers. DC resistance is approximately 10.5k and the coils are wound with 42AWG wire and fitted with six threaded, fully adjustable FeCrCo poles and six fixed Alnico 2 poles hidden under the cover. A thin steel reflector plate sits under the coils and the whole assembly is then mounted onto a nickel silver base plate.
This is just a small selection of some of the specialised pickups that I have made. A fair bit of work usually goes into developing these, but the trade off is that now and again the solution feeds into more traditional designs to and generates new product ideas. If you are making an instrument from scratch, restrictions on the shape and size of the pickups are removed and within the bounds of creating something that is aesthetically acceptable, the possibilities are endless.