I have mentioned in another post that the standard Ibanez humbucker pole screws are M3 x 0.5, screwed into the plastic bobbin. I guess this is what Ibanez would use, being the closest metric equivalent to the imperial 5-40 screws often found in DiMarzio and Seymour Duncan pickups. The plastic bobbin is rather soft, and 0.5 mm pitch will have less than 0.25 mm of thread in the bobbin per side, whereas the 5-40 is coarser, resulting in a “stronger” thread in the bobbin.
I was reaching over for a sip of coffee, and when I continued to adjust the pole screws on a set of V7 – S1 – V8 pickups, some of the screws had decided to strip in the bobbin. Just like that. Go figure. I was trying to coax the pickups to at least pretend to be interested in music. Using 5-40 screws would not help, seeing as the 5-40 screw diameter would be just under 3.2 mm, and the holes were already stripped to 2.9 – 3.0 mm. The next size up would be M3.5 x 0.6, or 6-32, the closest imperial equivalent I have on hand (6-40 is closer, but not a common off-the-shelf size). I decided to use 6-32 screws, with the coarser thread. Fixing the bobbins to keep the M3 screws is possible, but a hassle.
I made up a three-flute “tap” from a cap screw (nice steel), and kept it sharp. Tapping out the soft bobbin is not an issue, but the base plate, although soft metal, will blunt these tap edges. The holes in the baseplate are larger than 3 mm, the tap does not need to remove much metal (the 6-32 screw I used is close to 3.50 mm). Slow work. No easy reverting back to standard.
Misalignment between the bobbin and baseplate holes flexes the soft bobbin when the tap goes through the plate, so perfect alignment could not be achieved: Some of the new screws go a bit tight at the end. (I replaced the 15 mm long M3’s with ½” long 6-32’s.)
The head size on the 6-32 srews are, of course, much larger than the 5 mm of the M3 and 5-40 screws. I could turn them down to 5 – 5.1 mm, but decided not to bother now. Careful countersinking with fractional size drillbits, up to 5.8 mm, was required. Slow work.
The pickups look cool, athough with some scratches now (getting out stripped polescrews, with pickups in-situ, is no fun).
Sound? The idea seems to be that shorter screws will shift the tone to higher frequencies, and larger screws will shift the tone to lower frequencies as well as increase power. Add the screw to string (vs. pickup top to string) space issue as well. (For fun, I could turn down the heads, fit grub screws, fit cheese heads, pan heads, mild steel and high tensile, to see whether I can hear a difference. I will then, of course, also need to record samples to do frequency spectrum analyses on, to look at frequency response. With magnet type swaps as well. Maybe someday.)
There is a difference in tone. The humbuckers do have more output, switching from either humbucker to the single coil has a bigger drop in volume now. And, in comparison, the single coil now really displays a lack of musical talent. The bridge humbucker also shows a lack of musical talent, and is quite a bit lower in volume compared to the neck – it is a bit “stale” and “plain”.
The neck humbucker is a surprise, it is quite nice now. Open, not muddy (clean, as well as with light Tube Screamer input), bright, bell- like chimes, altogether much improved with some sparkle to it. The coil-split settings with the single coil is also a surprise: Paired with either bridge or neck, there is a nice “jangle” tone, with more sparkle on the neck split. The single coil – bridge setting is much livelier than the single coil or the bridge humbucker on their own.
To be continued.