Ok, I've made a magnetizing jig... now what?

[LtKojak]

I've made a jig with six Stew-Mac 1" magnets and a vise.

North in the right side, South n the left.

This is my question: I've got an assembled humbucking p'up. North on the slug side, South on the screw side.

How do I orient it in the jig to increase the magnetism? Slug side facing North or South?

Sorry if this is a stupid question... still hangovering from a wild New Year's eve!

[David Schwab]

I'd slide the magnet out of the pickup and do it that way.

Otherwise I'd think you have to pass it though the jig with the pickup's poles facing up.

I think Possum has magnetized humbucker magnets in situ.

[LtKojak]

That's it?

Anybody else?

Where's Possum when you need him...?

Zhang? Jason? Spence? Are they all hangovering too?

Damned New Year's Eve!

[Possum]

...

I don't think they will be strong enough to magnetize the whole pickup, I'm using a powered magnetizer which is very strong. But you can try it. All you do it put the screw side of the pickup up against the magnets so you magnetize that side as South, then the slug side will be north. Magnetize about the middle of the pickup side. This helps the magnetism get into the pole screws and slugs better than just putting a magnet in a pickup. I don't use this technique much though......

[Mike Sulzer]

This helps the magnetism get into the pole screws and slugs better than just putting a magnet in a pickup.

I do not think so. The screws and slugs do not permanently magnetize significantly. They "forget" the strong field you applied, and you are left with what the permanent magnet does.

[Possum]

....

Not true, the pickup will hold a significantly higher guass as an assembled unit, you have steel touching the magnet, everything is tight together, it will lose some but the ones I"ve done stay high. Some steel that some use is 1022 and probably holds a charge along with the other parts than lower carbon stuff. Duncan says somewhere on his site that they use this technique sometimes but no details. I never really found it to be of much use myself.....

[Mike Sulzer]

Not true, the pickup will hold a significantly higher guass as an assembled unit, you have steel touching the magnet, everything is tight together

Hard to believe, especially since there is not a lot steel and it is not very well coupled to the magnet. In a humbucker the purpose of the magnet is to magnetize the slugs and screws that magnetize the strings. The steel does provide a shorter path for the field lines connecting the north and south poles of the magnet, but why would this mean that you get a stronger field by magnetizing the whole pickup rather than just the magnet ahead of assembly?

[edwardta]

Happy New Year, everyone.

Regarding this topic, does anyone have (or have heard of) information as to how Gibson did things with PAF magnets when assembling PAF humbuckers? Did they simply install pre-magnetized magnets, or did the magnetize in-house? If they used a magnetizer, what type of magnetizer was used?

I have read references to how similar devices in commercial products are magnetized (not pickups, but other devices out there that have a permanent magnet along with some type of magnetic circuit). The idea is that the magnetic circuit is more "efficient" if the device is magnetized after assembly.

Edward T.

[Mike Sulzer]

Alnico, unlike modern material such as neodymium, can lose its magnetization easily. Magnetizing after assembly would assure that the bar is not accidentally demagnetized during handling.

Circuits involving large amounts of magnetic material can be hard to assemble if already magnetized.

[Possum]

..

You're forgetting one very important fact, steel acts as a "keeper" for alnico, preventing it from losing strength. A good example is a tele bridge pickup which has a steel plate coupled to the magnets. I have a '51 bridge pickup that is around 1200 gauss, the same as a modern fully charged pickup. The steel prevented the magnets from losing strenghth. The parts in a bucker are not "poorly couple" at least not the ones I make, everything is tightly assembled, my slugs are long enough to couple flatly against the magnet edge. Screw poles tightly into the keeper bar. When you charge the whole thing assembled instead of getting say 300 gauss at the poles you'll get about double that. I'm not sure what use this is though, its not really noticeably louder, Duncan says it has a use but I don't see the point in it as well as putting more strain pulling on the strings. All I can say is try it for youself, you'll need a real magnet charger to do it right. I remember reading somewhere in the old days that you should never disassemble a humbucker because it would lose something, which kind of makes sense, you break the magnetic circuit and the steel parts lose what charge they had. I notice something along these lines, a newly assembled new pickup sounds tight and bright the first day of playing, the second day it changes noticeably to get more "sag" and character, kind of annoying when testing these things.....

[LtKojak]

Thanks for the words of wisdom, Possum.

I've just got some non-charged A5 magnets, and I'm finishing my first humbucker ever!

My idea was to assemble the whole thing first and then magnetize it, but for the comments received my jig could be not strong enough to do it as I first thought... so to ensure the p'up is as charged as it can be with my jig, I guess I've got to do the following:

1. to charge the magnet by itself with the jig.
2. have the p'ups passed through the jig one more time once assembled.

Did I get that right? Or the second pass won't make any difference?

There's no way for me to spend all that money in a professional charger, mind you; I'm not doing this for a living, nor I intend to do it in the foreseeable future... unless I win the Lottery! Wait..! I'll have to buy the ticket first...

[Possum]

....

Well you can try it, but the only way to tell it worked is to have gaussmeter to read the strength at the pole screws. Yeah all this shit costs money, chargers, guassmeters, LCR meters, etc. etc. You could buy 2 of those neodymium blocks someone posted here, those are certainly strong enough to charge a humbucker assembled with, those things are incredibly strong, you have to be very careful using them. Before I got the charger thats what I used for the most part. They aren't real cheap but I think that one was reasonable.

[Mike Sulzer]

You're forgetting one very important fact, steel acts as a "keeper" for alnico, preventing it from losing strength. A good example is a tele bridge pickup which has a steel plate coupled to the magnets.

Actually i was thinking of a keeper when I wrote above that the steel parts in a humbucker provide a partial path from the north to south poles. You think the tele steel plate acts as a keeper? Seems unlikely that it has much effect, but who knows? The traditional keeper provides a direct path between the two poles. The tele plate, not so much like that.

Alnicos can lose magnetization from mechanical stress, such as being dropped. A proper keeper on a horseshoe magnet reinforces the flow of the field lines around a loop, and makes it much harder for any of the magnetic domains to flip under stress.

When a magnet "charges" a piece of steel does it lose some of its inherent strength? You should know the answer to this.

If the humbucker charged assembled is not any louder than one where a charge magnet was slid in, does this not imply that the field strength is not significantly different?

When you take a humbucker apart why does it matter that the steel part become demagnetized? Does the magnet lose some of its strength every time it comes in contanct with the steel?

[Possum]

....

When a magnet comes in contact with steel, well, no the magnet will get stronger on the pole that is not contacting the steel. A tele baseplate actually boosts the gauss at the poles, maybe thats why sometimes its called a "reflector" plate. Alot of the DeArmond pickups used very thin alnico magnets that over time would probably completely discharge, he used steel base plates on all of those designs and they have held their charges for nearly 60 years. I use similar magnets in similar designs, if you measure the gauss on the top of the flat it will read about 200 guass, put it on a steel baseplate and it reads around 260. A baseplate also changes the sound, without a base plate the sound is more free flowing, put a steel baseplate on it and the tone gets harder and less yielding sound.

I don't think "loudness" has a whole lot to do with magnet strength, a full charged strat pickup is about 1200 guass, I have dropped them down to 400 and they don't really get noticably less loud all that much, it gets a little less crisp sounding and you gain sustain because its not pulling on the strings and damping vibration.

There is some weird voodoo thing in humbuckers, when you pull them part, you're breaking up a unit. I notice that if I change pole screws to a different set, the new screws will sound bright and tight sounding, 2 days later they loosen up and the tightness goes away. Its the same thing with a "new" humbucker, the first day of playing it will sound too edgy and bright, 2 weeks later its all settled in and opens up tonally. When I test stuff I have to remember to give it a couple days to really hear what its going to do....

[Mike Sulzer]

When a magnet comes in contact with steel, well, no the magnet will get stronger on the pole that is not contacting the steel. A tele baseplate actually boosts the gauss at the poles...

True, but does it make much difference as a keeper with a long tele rod? A thin alnico, yes, I think that is right.

I don't think "loudness" has a whole lot to do with magnet strength, a full charged strat pickup is about 1200 guass, I have dropped them down to 400 and they don't really get noticably less loud all that much, it gets a little less crisp sounding and you gain sustain because its not pulling on the strings and damping vibration.

I do; when I increase the magnet strength the pickup gets louder.

There is some weird voodoo thing in humbuckers, when you pull them part, you're breaking up a unit. I notice that if I change pole screws to a different set, the new screws will sound bright and tight sounding, 2 days later they loosen up and the tightness goes away. Its the same thing with a "new" humbucker, the first day of playing it will sound too edgy and bright, 2 weeks later its all settled in and opens up tonally. When I test stuff I have to remember to give it a couple days to really hear what its going to do....

I have never tried to observe this; something for a rainy day.