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Pole Spacing

I’ve written this out in email for about 4000 times by this point, so, hopefully, this is going to be fairly straight forward nowadays, however, it’s one of those things that delves a little more into myth and legend then it does into math and science, so it has the potential to get away from me a little. I shall try to keep this fairly concise.

Simpler times, simpler designs.
When Humbuckers were invented in the 1950s (atleast, as in a form we’d recognise today) by Gibson®, they came in one size, one shape, one spec. Pole spacing was 49.2mm (approximately, these things were being made in the fifties in relatively small numbers, tolerances weren’t as tight as they are nowadays), centre to centre on the E to E, there were no specific neck or bridge versions (the neck pickup was simply installed with the pole screws pointing towards the neck and the bridge had them pointing towards the bridge) and that’s the only way humbuckers were made until, at least the 1970s.

Its, honestly, not perfect – it’s VERY rare for any electric guitar to have a string spacing (at the bridge saddles) of anything less than 52mm, and if you look at any old Gibson® guitars, you can see that the strings don’t sit over the poles – I doubt this was intentional, but, honestly? It doesn’t affect the sound of the pickup in the slightest. It’s purely a cosmetic thing, and, well? You’re in good company I suppose considering Gibson®, to this day, produce most of their humbuckers in 49.2mm pole spacing.

And, if Gibson® were the only company to make guitars, that would be it! One spacing, no necks, no bridges, just humbuckers, and my job would be easy! However, that’s not the case I’m afraid.

The 1970s – Disco, Punk rock, and Copyright violation
I’ll spare you the history of lawsuit guitars, because, chances are, if you’re looking at winding your own humbucker, this probably isn’t your first rodeo, and your more than familiar with “what went on in the 70s in Japan” – however, whilst this period of guitars has a few weird twists and turns within the grander scheme of things, lets focus on some of the weird stuff that happened with the pickups!

In short, when Hoshino Gakki (and whoever else was making the Tokais, Grecos, Burnys and Ibanez’ at that time) decided to essentially, copy, Gibson guitars (I think I’m on safe ground here, all this was put to bed in 1977!) they were doing it without really knowing a great deal about electric guitars (the entire idea being just over 20 years old, and Japan having a somewhat “frosty” relationship with the USA, I can’t say I’m overly surprised) and, seemingly, they’d not seen a great deal of them to actually base their “designs” off of, so, as you can expect, some things “got lost in translation”

The first, and most obvious “error” was one we’ve all likely made (multiple times if my returns emails are anything to go by!) – The messed up the pole spacing. 49.2mm (which is actually an imperial measurement, approximately, 1 15/16”) is seemingly, an insane level of accuracy for a non-critical dimension on a musical instrument part, and, Japan being a metric country, simply rounded up to 50mm.
And, the 50mm humbucker was born – functionally no different to the original design, just “made metric”

However, our Japanese brothers didn’t stop there!
Seemingly very early into their forays into this, they spotted the “bug” with the poles not lining up over the poles on the bridge pickup!

So… they’d set out to fix it – and, honestly? They actually did a pretty good engineering job on it! They (and I think you can spot where I’m going with this) made humbucker bobbins with a 52mm pole spacing, which brought the poles in line with the strings, AND (the clever part) to account for the increase in internal length of the bobbin to accommodate the poles, they increased the external length too, taking them from 66mm (which is the length of a the Gibson® bobbin, and, to this day, all 49.2mm bobbins!) to 68mm! (this has become mixed up a little over the subsequent years – 52mm bobbins are always 68mm long (as are 52.5mm, but more on that in a second!) and 50mm bobbins get a little muddled up. Sometimes they’re 68mm, sometimes they’re 67mm, sometimes they’re 66mm (ours are always 67mm)

Either way – we’ve got the very first “specific” neck and bridge humbuckers at this point! 50mm necks, 52mm bridges! And these lawsuit models got everywhere! (we still get emails asking for their parts to this day!) They were, by and large, very good!

But, it was too good to last, and Gibson® (and Fender®) went in with the legal hammer (as they had every right to!) and smashed up the whole thing. Hoshino Gakki would go to cement its Ibanez brand as something completely different to what it was in the 1970s, but the dye had been cast for humbuckers – Pandora’s box had been opened! Pole spacing had become a mess.

The Imperial “flip”
With the rise of the lawsuit guitars, Gibson® decided to get their jazz guitar brand out of mothballs and put it to some use in the far east in a real “cant beat em, join em” moment in the early 70s, and approached Matsumoku (Aria) to rebadge some of their models as Epiphone® – things like the Crestwood, the Wilshire, the Riviera, the Sasino and the Sheraton – all fairly kooky designs frankly (or keeping in tune with the Jazz thing Epiphone originally was) – and with these models, Gibson® gained access to 52mm spaced humbuckers.

Now this is purely hearsay (because no one’s really documenting this stuff!) but, presumably, Gibson® got good feedback on the pole spacing lining up with the strings over the bridge pickup, and approached their bobbin manufacturer, asking “make this for the USA stuff” – and, in the same way Japan made a rounding error from imperial to metric, the Americans made a rounding error going the other way – 52mm became 52.5mm (2 1/16”) (they even retained the 68mm bobbin length too!)
(And, if you’re interested in the history of this sort of stuff – Matsumoku were also making 48mm spaced pickups too – presumably another rounding error! It’s near extinct on humbuckers nowadays, but does survive on P90s and sometimes, single coils!)

Too many sizes! Too confusing!
Now, I’ll be the first to admit – it’s stupid. Considering pole spacing doesn’t really matter – the idea that we’ve ended up with 3 “common” sizes (49.2, 50, 52/52.5mm) (AND, at least 5 “uncommon” ones, which I won’t touch on here!) is laughable. Sadly, it’s the world we live in as pickup winders, so we’ve got to make the best of it.

So, it’s probably worth de-mystifying all of this a little.

52/52.5mm
First thing to address – 52mm vs. 52.5mm? Believe me or not, they are 2 different things… there exists parts in both sizes – however, they are, by and large, entirely cross compatible. A 52mm cover will fit onto a 52.5mm bobbin will fit onto a 52mm base, and a 52.5mm cover will fit a 52mm bobbin which will fit a 52.5mm base. (the only thing that needs to match the bobbin, is the keeper bar underneath) – in short, you’ve got 0.5mm of tolerance. It only really affects 52.5mm vs. 52mm (50 vs 49.2mm is over 0.5mm so the rule doesn’t apply) – so, to keep things relatively neat, we only stock the 52.5mm parts in kit form.
52mm spaced parts do exist, but, the bobbins are generally pretty cheap and nasty, so we’ve been avoiding them for a few years at this point.

Generally speaking, 52.5mm (or 52mm if that’s what you’re working with, I won’t judge!) is what some people will call “F spaced” – this is a bit of a weird name to be honest, because I think we can all agree that the “F standard for Fender®” – it doesn’t I’m afraid. I’ve no idea where that came from to be honest – I *think* it might stand for “Floyd” as in Floyd rose®, but don’t quote me on that. Either way, a Fender® Strat®, at the period of 52/52.5mm humbuckers being released, would have had a string spacing of 2 7/32”, or 56.4mms, E to e string – that is definitely, not 52.5mm, and it will not match up – however? If your working with a tremolo, 52.5mm is about as wide as your ever going to get on a humbuckers pole spacing, so, just like the Gibson® guitars of old? Embrace it. 52.5mm humbuckers are your best choice.

Its also, a great choice for a bridge pickup if your trying to match up strings to poles on Gibson® or Epiphone® guitars, or anything with a tune-o-matic/ABR style bridge.

However – be aware, when winding your 52.5mm humbuckers, that the internal is longer, so your winds are long, and as such, your pickup will have a higher resistance then if it was a 50mm or a 49.2mm.

50mm
Slightly more straight forward thankfully – 50mm is 50mm – its most commonly used as a “neck” pickup as part of a “matched set”, with a 52/52.5mm in the bridge, in an effort to keep the strings lined up with the poles. However, its often used “wrongly” with people assuming “50mm = neck, 52mm = bridge” – its true, most of the time, if you’re using a Tune-o-matic or ABR bridge – its not always true with tremolos – you’ll sometimes find that you get a better “string to pole” match by using a 52.5mm in the neck, especially with vintage spec Tremolos.

Electrically, you’ve not really got a lot to worry about though – they’re marginally longer internally then 49.2mm bobbins,  but they’re longer externally by a greater degree (56mm vs 55.5mm internal, and 67mm vs 66mm external!) so you’ve a little more breathing room on a 50mm bobbin compared to a 49.2mm – handy for slightly more “modern” builds if nothing else!)

And, if your torn between 50mm and 49.2mm? Remember, whilst 49.2mm spacing is “historically accurate” – you’ve got WAY more options in 50mm when it comes to bases, covers and blanking plates. Might never come up, but, equally, it pays to be flexible with your designs, and 50mm gives you a lot more scope to make unique pickups!

49.2mm
The grand daddy pickup spacing! Your poles wont line up with your strings, they’re the smallest internal and external, and your limited on options when it comes to covers and bases. Doesn’t have a great deal going to it as a spacing I suppose, BUT, its what was done originally, and its likely what will be used until the world stops turning for American manufacturing!

Frankly, from a “what its doing in a guitar”, its no different to a 50mm spacing, but it does have a few little quirks that have carried over from its original, American/imperial roots.

The main thing to bare in mind, is that the screw side bobbins will only take 5 - 40 UNC bolts – M3 bolts (which are what most pickups come with nowadays) wont bite into the plastic – so, its 5-40s you’ll be needing (and its what you’ll get with a 49.2mm kit, even if you specify M3s!)

Interestingly, using 5-40 bolts on the screw side will actually increase the inductance of that coil (because of the higher ferric content (the thread diameter is 0.1-0.3mm wider, meaning more iron)) so, strictly speaking a 49.2mm spaced pickup has the potential to be “hotter” (although, there’s nothing stopping you using 5-40s rather then M3s in 50mm or 52.5mm spacing, so, its maybe a moot point)

And all that said? It’s a great spacing if your looking to “meet your heroes” – it’s the spacing, that was used on the original Humbuckers, and, whilst your limited in certain options (your probably not finding a triangle legged, 16 degree slanted, black plated low profile base in 49.2mm!) you’ve got a couple of “vintage correct” options that are pretty cool! (covers without copper under plate, threaded base plates etc)

Really though, its not the spacing for everything (although the amount of Seymour Duncans I’ve seen, spaced at 49.2mm, shoved in the bridge slot on a HSS strat, with the strings missing the poles by a good 5mm, would have me thinking maybe it is!) – I’d probably avoid it on trems, and I’d probably avoid it if I was making something “very modern”… its great for a vintage build destined for a Gibson® or Epiphone® though.

How to Assemble

It’s quite difficult to boil down “how to build a humbucker” in a nice, bite sized little article that anyone could follow frankly. I certainly wouldn’t go as far as saying its particularly difficult per se, but there’s a lot going on, there are a few different ways of doing it, there’s a few “standards” you’ve got to bare in mind, and, ultimately, you’re going to find your own way of building a pickup, and you’re not going to do that without making a few mistakes along the way, so, with all that in mind? I’ve written this up, and taken photos of the process of “assembling a humbucker” using the parts from this kit – but its so far from comprehensive that it will only take you so far, and it wont cover all the mistakes you WILL make.

Now the first thing you’re going to see, are a pair of coils! You’ll notice I’ve not even touch on winding in the photo dump below. Frankly, how you get the wire on the bobbins, is completely up to you – you can find it with a CNC winder, you can wind it with a hand fed motorised winder, a manual winder, a jig in a drill, a converted fishing reel, or, if you’re utterly insane, you can do it by hand, one wrap at a time! What I will say is that our process, will be different to yours, and the actual winding process is more dictated by your machine/equipment then some over arching technique you must follow – do whatever works for you! Frankly, you’ll soon realise that how you wind has very little impact on the tone of a humbucker anyway. More on that later!

So, before you do start winding those coils – you’ve got 2 things to remember.

1. ALL HUMBUCKER COILS ARE REVERSE WOUND (Counter Clockwise) – no one ever believes me when I tell them this, but its true! The slug coil and the screw coil are both reverse wound. When we terminate them, we reverse the reverse on the slug coil, making it a standard wind, so electrically, one remains reverse, and the other isn’t, but physically? They’re always reversed. Also, its worth remembering, they’ve GOT to be reverse wound, because its standardised. Its industry wide! And, better to have your humbucker compatible with every other humbucker then not.
2.  SLUG COIL IS ALWAYS NORTH POLARITY, SCREW COIL IS ALWAYS SOUTH POLARITY – I’m jumping the gun here, because your not worry about the magnet before you start, but, just remember that OK? I will, out of force of habit, call the slug coil the North coil, the screw coil south coil (especially with these photos because it’s a 12 screw humbucker we’re building!). Now, this is a standard, and its worth remembering – BUT – its not always true (HSS guitars should have their polarity reversed)…still, worth remembering!

Phase & Polarity

Heres where things get, potentially, a little confusing, so i'll try not to get bogged down too much, but, trust me, its reads worse then it actually is!

So, remember when i said "All humbucker coils are wound reverse"? Thats true! And we simply wire one of those pickups in reverse (reversing the reverse!) to make it "standard wind" - and thats how you "buck hum"! However, you've probably realised pretty quickly that "Reverse wound" and "Standard wind" aren't really suitible descriptions of whats going on here, because they're relative. So, form here on in, i'm going to introduce "Clockwise" and "Counter Clockwise" too, because theres no confusiton there.

Its as you think really - with the bobbin pointing "up" as it would in the guiter, the wire it wrapped around it in one direction - it'll either be clockwise or counter clockwise. Easy as that! (and it had better be counter clockwise!)

So...

ALL HUMBUCKER COILS ARE WOUND COUNTER CLOCKWISE!

Please, for my sanity, if nothing else, follow this rule! Its true for every humbucker ever made. It will ensure that your pickup will work withe every other pickup on the planet, and you wont be fielding phone calls asking why you pickup has broken someones guitar.

So, at the risk of repeating myself - we've got a pair of counter clockwise coils, with the starts and ends clearled IDed.

Now, humbucker coils are actually wired together like this - Start to Finish to Finish to Start, and that "finish to finish" is whats reversing one of the coils. Ontop of this, the polarities of humbucker coils are standardised too. The Screw Coil is always on the "South" side of the bar magnet, and the Slug coil is always on the "North" side of the magnet.

I'm well aware, however, that not all humbuckers are Screw/Slug, so we cant really use that terminology either, so, we have to move away from that too. We'll call them the North and South coil! Just remember that the North bobbin is the one sat on the north side of the magnet, and its pointing "in" on the guitar (towards another pickup) and the South bobbin is on the south side of the magnet, and will be pointing "out" (towards the neck in the neck slot, and the bridge in the bridge slot) when its on the guitar.

And in the grand scheme of things, those two coils are going to wire into the guitar so the South Coils Start is grounded, and the North Coils start is live (the two finish connections are called the "coil join", or sometimes, the coil tap (or split), we'll cover that later!)

There are exceptions to these "rules" - but, 99% of the time? This is what you'll be doing.

This might seem a little like we're jumping the gun here, but it will come back around as we assemble the humbucker.

Colours Explained

I think this is a little bit redundant to be honest, because the site has the "smart swatch" system, which shows you how everything looks once you've assembled it, and whilst its a bit "too perfect", it is pretty accurate to what your going to get. However, i will concede that sometimes, real pictures of real things, can be helpful, so, heres another photo dump, detailing as many of the colours as i can.

Bobbins
Humbucker bobbins are injection moulded plastic, and are the same colour, top to bottom, and are all one piece. Once they've a coil wound onto them, you cant change the colour (as you can with a single coil, by replacing the cover), so, when picking your bobbins colour, go in knowing, once its wound? Theres no going back!

Expectation vs. Reality

I’ve been going through the site in recent months, and “myth busting” a lot of stuff to do with pickups and parts, and even on this page, I’ve laid bare a lot of what’s going on with humbucker covers and how they’re going to affect your sound, both positively and negatively, and, personally, I like being honest about this stuff. If you know what to expect, then we all come away from this a whole lot more fulfilled, and no one has to sit there and gripe after falling for a marketing hype and flowery descriptions.

And in that vein (and this is a good rule for the whole of the internet!) – remember, every photo I’ve put up on this website, is “the perfect example” of what the thing should be. It’s been edited, tidied up and made to look immaculate.

Now, honestly, I wish that every single part I unpacked and stored on these shelves, was finished to the level of the ones in the photos (It’d make my life easier, and I wouldn’t have to write this!), but let’s be honest, that’s not the case.

These are, in the grand scheme of things, pretty affordable parts – they’re well made, well plated and generally, higher end examples of what they are…. But they’re still “affordable” – £2 bobbins, right? Go into buying this stuff, knowing that, if you look closely enough, you will find something wrong with them. There are ALWAYS minor imperfections in guitar parts.

That’s not to say that the majority of covers won’t be “very close” to perfect, nor is it to say that we wash our hands of “real” faults, but I do have to ask, that we all have some realism with this stuff. It’s a £5 part (at most)– its not a £50 cover or a £25 bobbin (although I doubt, they’d be any better) – expecting superior grade, faultless electroplating, 24 carat gold, tolerances down to 0.001mm, hand polished plastics, or whatever, is wholly unrealistic. I appreciate that you may be fitting these to a pickup that you’re selling for £500… I appreciate you might have a really picky customers yourself, but Axesrus® does have to draw the line somewhere.

We will not replace parts with what we consider normal levels of imperfection.

We WILL accept them as returns, and refund as per our Ts & Cs in regards to “unwanted goods”

I’m not saying these parts are cheap, second rate, and riddled with flaws you understand? They are, really, some of the best parts I’ve worked with, and we do have a very high level of quality control both at manufacturing, and in house when picking and packing. But, really, no one is spotting an isolated a 0.25mm “dimple” or “divot” in a finish, or a 0.5mm scuff. (and that’s how small these flaws are!).

And remember too (and this is scant consolation to anyone making pickups for a living, because you will suffer this just as badly as we do) – minor imperfections that look minor on the part, vanish once the part is fitted to a guitar. We’re damned by looking at this stuff under the microscope of isolation, and, in reality, that £10,000 guitar you’ve got hang on the wall? I guarantee, has exactly the same manufacturing imperfections in its parts.

So, with that said, and in an effort to be WHOLLY honest, here’s a what I’m talking about.