Mini HB parts needed and a few Qs

[Peter Naglitsch]

I would really like to try my so called skills on some Mini-HBs. When reading up I found out that there is a distinct difference between a firebird type of mini and the later type minis with exposed screw heads. As I have understood things the firebirds have their bobbins surrounding the magnets directly while the ones with exposed screw heads are essentially traditional HBs engineered to be…smaller. Only exception is the steel blade instead of six individual slugs on the non adjustable side and the lack of a keeper bar. And then there are some early Epiphone pickup called the New York pickup or similar that is a sidewinder SC in a casing very similar to the later Gibson minis with visible screws. Have I got things right?

So now I have to find parts for both types of pickups. So, anyone got a source for Mini Humbucker parts they would like to share?

GJ have base plates (holes and no holes), covers (holes and no holes), bobbins for blades/magnets and magnets to fit in the bobbins. The bobbins seem to need a bit of tweaking to be able to fit a blade/magnet. And they do not list mini HB screws. I E-mailed Pat and he wrote that they will receive screws to match their covers this week. That sounds a bit too much of a coincidence. I can live with the blade bobbins (I’ll figure out a way to get them to work with the magnets) but I don’t wanna be left hanging there waiting for Pat to really deliver stuff that I’m not 100% sure he really has at the moment.

So, is there anyone that has an alternative source for mini HB parts?

Oh, and another question if you guys don’t mind; how are the screws held in place? The pictures I have found on the internet indicates that they are held in place buy threaded holes in the base plate, but I have not been able to find any really good pictures. Anyone have the facts? And I would love to see pictures of the inside of both types as there is a real lack of pictures to find.

Thanks guys

[J S Moore]

Try Allparts. Mini parts are not listed on the website, you have to phone and ask.

All the different styles share the same parts. In addition to the magnet in the bobbins for the Firebird style there is a ferrous shim underneath to couple the magnetic field. The screws do indeed screw into the baseplate.

[Peter Naglitsch]

Thanks for the reply. So you say that firebird and later minis used the same bobbins and magnets? Perfect. If Pat really can supply the screws I have at least one source for the parts.

I'll try Allparts and start with an E-mail. Phoning from the other side of the Atlantic tends to be costly...

And yeah, I knew about the shim under the bobbins. You don't happen to have the specs on that one?

Thanks once again.

[J S Moore]

Probably made out of the ever popular "soft iron". I only have a sketch but it goes to just either side of the magnets. The Johnny Smith version used a plate that covered the entire bottom.

[dpm]

I have question on the same subject so I'll ask it here if that's cool - does anyone know roughly how many turns of single build 44 wire could fit on a mini humbucker bobbin?

[Zhangliqun]

The bobbins for Firebird and Deluxe style minis are the same because the screws on the Deluxe-style mini screw into the baseplate, not into the bobbin. Firebirds and Deluxes are essentially the same, just a no-hole cover and two "bar slugs" for the Firebird, verses 6-hole cover and one bar slug, 6 adjustable screws. (I don't know if that's how Gibson did it back in the day, but that seems to be how mini's in general are done now.)

The sound is probably a bit different, though I've never A/B'd them in a guitar so I can't say for sure.

Also, the bobbins are not secured to the baseplate, they are held in place by the cover, which is why you never see uncovered mini's, except maybe if you happened to see one of my kooky little designs floating around out there.

[Peter Naglitsch]

Thanks Zang

I have tried really hard to find any pictures at all of the guts of a Mini HB but without much luck. Do you mind directing me to where I might find pictures of yours? If not possible that’s still cool. I think that I have the most parts figured out by now, construction-wise

Oh, one thing, would you like to expand on the sonic difference between Firebird and Deluxe minis?

Still learning...

[anderekel]

I found this a little while ago, lookin' to try my hand at winding sometime. http://www.guitarattack.com/winder/minihum.htm



I found that image on ebay and figured it would be helpful as well.

[Zhangliqun]

Thanks Zang

I have tried really hard to find any pictures at all of the guts of a Mini HB but without much luck. Do you mind directing me to where I might find pictures of yours? If not possible that’s still cool. I think that I have the most parts figured out by now, construction-wise.

Somebody's got a good shot of the guts of a mini floating around the internet, LP Forum, Duncan Forum, couple of other places. I bet somebody in here may have a link. I have no pictures of my own crap yet -- don't even have a decent camera (yet another thing to take care of when I get out of debt)*.

But basically the bobbins are "hollow", just a big long rectangular hole where the blade or what I call the "bar slug" fits. Because of this huge hole, there is nowhere to put a screwhole to screw the bobbin to the baseplate. Hence the need to leave the cover on.

*(Though one guy took a couple of decent pictures of a zebra mini that I made him by shaving down two standard humbucker bobbins and mounting them on a minihumbucker baseplate. Because they start as standard humbucker bobbins, it uses standard size polepieces and slugs so it looks like a skinny zebra humbucker. And because they have the standard mount screw holes, they can be mounted to the mini-plate. Naturally I had to sand and polish the bobbins after the shave-down so it looks like something. And of course, you have to modify the baseplate too.)[/QUOTE]

Oh, one thing, would you like to expand on the sonic difference between Firebird and Deluxe minis?

I don't have much direct experience with Firebird mini's because the Firebird covers I've been able to find just kill the tone, which is a big part of what caused me to make the aforementioned zebra mini. Tone can't be killed by a tone-killing cover that's not there...

Thus I'll defer in part to folks in here who have some experience with both Firebirds and Deluxes in the same guitar, but that said, from the design differences I can give an educated guess, and said folk with real world experience please check/correct me as needed. The Firebird version probably has less drop-out on string bends because neither coil has any space between poles because they're both one long bar/blade. I suspect the Firebird version is a little beefier overall because the bar is a shade wider than the little mini screwheads. All of this is, of course, assuming all other aspects of the two pu's are the same, ie, same magnet, same wind, same wire guage, same number of turns, etc.

[David Schwab]

There's two kinds of firebird pickups. One is the mini humbucker with the 2 alnico blades and closed cover. The other which was designed and patented by Bill Lawrence, was an odd sidewider design, with the magnet up the center, and the sideways mounted coils only having a steel core, and they sit in the neutral space between the N & S poles! He says in the patent that they act only as inductors. (Pat 3902394) I think they were used in the Thunderbird bass too.

Here's that version. Looks like it used the same mini bobbins. They still had the patent number used on the PAF which was really Les Paul's patent for his trapeze tailpiece.

[Peter Naglitsch]

Anderekel:
Thanks for the picture. I had found the guitarattack link before but that picture was new to me

Zang:
Thanks again. The idea of a zebra mini is really cool. The picture is almost complete now…

David:
Really cool. That explains why the minis are sometimes referred to as sidewinders. I have not seen that type before.

[Peter Naglitsch]

After a way too long time waiting for GJ to answer questions I finally got the parts from Allparts. For future reference I'll post the parts numbers and current list prices here. And they only carry Deluxe style parts, no Firebird parts.
Parts order number current list price
Baseplate (with hols) PU 6915-001 7.50$
Alnico bar (short) PU 6918-000 6$
Pol screws GS 5453-001 5$
Slug bar PU 6914-000 4$
Bobbins (2) PU6910-023 5.50$
Covers (2) PC 0308-010 24$

The screws are nickel and the cover are chrome but it looks OK anyway. The covers seems to be nickel-silver (not brass anyway) as is the baseplates. The screws are a bit loose in the base plate but that will probably get better when it is all potted. The only disappointment was the look of the baseplates. They look tarnished or even rusted. I’ll see if I can polish that away…

More reference:
As electricdaveyboy pointed out in another thread the mini parts from GJ are all brass.


I try to snap a few pictures and post later on.

[Peter Naglitsch]

Pictures as promised

baseplate with screw:


"the kit":


before putting the lid on:


completed:
http://www.peternaglitschluthier.com...s/DSCF2949.JPG

The initial feeling is intact; good parts, nice fit, really nice plating on the cover but a gross looking baseplate. Now all that remains is to take that beauty for a test ride...

[belwar]

I recently bought a dozen mini baseplates from AP and I dont recall them looking like that at all! They looked quite good if I remember. The cover was decent quality as well. The bobbins are so-so. I dont like the scratchy marks on them ... though that does make them authentic. Whoever made the original gibson mold didnt polish the inside leaving rough steel milling marks on it. They are actually fairly sturdy for their size.

Also did you notice that while the steel blade fits, it's just cheaply stamped and doesnt fill the slot well?

I think im going to send the blade from the gibi I have and find out the alloy. I could make those blades so easy on the CNC. My gut says the material is either 1010 or 1018 which is readily available. I'd like the know the alloy of the pole screws but I bet 1022 would work just fine.

Oh, do you have a set of calipers that you could measure the head of the mini screw? I'd love to know the AP screws measurements

[Peter Naglitsch]

Yeah, forgot to mention the blade. It is not the prettiest I have seen. The main issue is the length of the blade The slot in the bobbin is 54.04 mm or 2.126". The blade is 51.86mm or 2.041" so there is a gap to fill. Thickness is a good match thou

The magnet is 58.24mm or 2.293" so it will not work as a firebird magnet.

The measurements for the screws:
over all length 19.21mm/.756"
threaded length 10.50mm/.413"
diameter (un-threaded part) 3.35/.131"

I have no idea of the thread size as I'm really a 100% metric guy and those threads are not metric...

I would really like to help but I have nothing to compare/test with, sorry

And you're also right about the look of the bobbins, but as they will be used with a cover that's really no issue for me.