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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.

modulator Hiya @modulator - I fixed two - did I miss any?

There's a issue with the code generating the embedding code, since the forum upgrade - I'll fix what I find manually till Norio can work out a fix.

      To evaluate the effect of screw size in the V8 bridge humbucker, I cut up sections of 2.5 mm welding rod (nice soft steel) to throw into the screw holes (the magnet keeps them in place). This represents the minimum diameter of screws likely to be used in a humbucker. To facilitate removing them, I had to make them long enough to sit on the pickup cavity bottom, so that they do not drop in too deep and I can grab them with needle nosed pliers. They also represent an extreme setting of screw length below the magnet. Again a mix of variables, supposedly leading to lower magnetic field strength at the strings, with too much length at the top, more magnetic field at the strings.

      I also played without polepiece screws in the bridge humbucker - It is quieter, almost the same output as the single coil. I would say a very hot overwound singlecoil? No sparkle, a bit heavy on the bottom, a bit dead, but, it has that sound I guess they call “vowel” and “aw”. Would be fun, if it had sparkle to it as well. I like the effect, though. The effect is more prominent on the middle strings. High E is a bit low on volume. Lower fret picking brings out a nice tone, caused by the unbalanced coil output? This type of sound, with single coil sparkle, might be nice to have at hand.

      As for the pole rods, the output is up a bit, and the sound is slightly better. A bright, but not too bright tone, still no sparkle, but less of that “aw” sound though. Splitting with the single coil (slug coil of the humbucker) has also lost the tone it had with the full-size screw heads. In fact, it sounds very dark. Of no use. Maybe splitting to the screw coil would help. Maybe a set of 6-32 “grub” screws in the bridge is required. I found removing the rod under the high E string also influences the tone of the B string. Removing that short rod under the G string did not make much difference. But the string-to-string balance was nice with these rods in place.

      For the rest, this set is now tolerable, even if the single coil lacks imagination (and has an irritating too loud G string output. Must fix that.) The overall high-ish output requires that I keep the volume settings low to get a clean sound, I would prefer more headroom. My experience to date indicates that high DCR pickups do not deliver the tone (I think) I want. In the long run, this V1 – S1 – V8 set might have to go into storage anyway. Or the V7 goes to bridge, a lower wind single for the middle, and a low wind humbucker in the neck?

      I made up some grub screws for the V8, by sawing off suitable lengths of threaded rod from long 6-32 cap screws. Simple slot for a screwdriver, lengths between 12 mm and 14 mm to try and even out the depth at stagger settings.


      Ouch. Well, if I do not like these pickups, I could sell them as “relic-ed”.

      This setup is not too bad, but weak on the treble side of things. The coil split with the middle single has some of that jangle, on it’s own it is still a bit lifeless. I guess there is only so much one can do with a high DCR pickup.

      I re-fitted the cap screws, worked on screw heights, tested with the G string screw removed, with grub screw under the G string... String balance is good without a screw under the G string. But the tone does not quite match the B and E strings. Slightly better with the grub screw. I shall make up a small-head cap screw, and use the V8 like that, until a suitable bridge pickup is located. Interesting, and some knowledge gained. Such as screw out the high E string polescrew much more than before, to get a volume and tone match with the B string. With the B string screw lowered a bit to compensate. I suspect the high E will always sound weak and thin, and some compromise with volumes and tone across strings and pickups will have to be accepted. The single coil responds to settings only so much, I suspect the two humbuckers have a big enough influence on the string dynamics to mask the differences.

      At least the pole screw threads in the bobbins are not stripped anymore.

      Thanks for fixing the photos, hope you guys get the system sorted.

      • V8 replied to this.
        3 years later

        modulator Would be fun, if it had sparkle to it as well

        In a humbucker? Especially a stock Ibby from a shred stick? 😆

        I've converted my pimpocaster to a H/S (bridge/neck) and I'm happy as a pig in - the H+SC combo is kinda tele-esque, neck = strat and bridge = shreddy. Not sure why anyone would want more, but I guess we all do!

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