New Mojotone Butyrate humbucker bobbins. How accurate are they ?

[JGundry]

I was going to say. T-Tops., PAFs, 57 Classics, Burstbuckers, 490R, and 496R all have the same pole screw spacing, and the Allparst plate is the same as well. I was totally thrown off that Jon said Allparts backing plates will not work with T-Tops.

All Parts baseplates will "work" with a T-Top but they are not correct. They are slightly off and if you want the cover to fit properly you are way better off with the correct spacing if you are repairing a vintage pickup.

[WolfeMacleod]

Maybe i'm lucky but I came across two of those three very easily without help. The Keiyo link I found by asking Jay @ stew mac... Both Jason Lollar and Don Whittemore (luxe caps) gave me the name of Gavitt

Stewmac knows Keiyo because of me. I was their hookup in 2003 because of Allparts problems keeping parts in stock. Spent spent every night from '98 till that day searching to find out who the manufacturer of those bobbins was.
Gavitt, also came from my research..I told Jason.....not sure where Don got it though. Nobody knew of them before. I believe it was 2002 when I found them.


By the way, I found several employees of HPI tonight and have set contact in motion. The original founder may still be alive...at around 100 years old.

[Possum]

Sorry Jon, I disagree, those old guys don't remember precise technical details of actually smelting and processing the steel to final stock, the stuff we found out isn't in any book and the old guy at the plant was more helpful in pointing out what was wrong with a particular bad batch of steel that made the original VL set suddenly go way wrong. In fact, that disaster pushed me into questioning everything I thought I knew at that point and starting over literally from scratch is when I learned the most valuable information. The guy who helped me was just as curious as I was and surprised at what we found. If you want to think talking to some old timer is going to get you anywhere I'd bet against it. They can't tell you minute details that went down then and you can only know by examining real examples.

I had access to an old timer who worked at Gibson during PAF days and he literally knew nothing about steel and told me to go buy ten penny nails and it'd be good. I don't quite understand your resistance to knowing there's a deeper story, you know me, personally I kept asking questions and more questions even when I thought I was done. Then something would come up and more questions would appear. It took most of 5 years just on that subject alone to run out real data and details on how stuff was made in great detail. You would literally have to own a steel smelting and cold processing plant to get closer and unfortunately they don't smelt steel the way they used to, so you don't find an abundance of certain chemicals back then due to how they did that process. The best you could do is find some 50's steel and it would have to be in those particular sizes, you couldn't just cut larger stock up and get the same results. These are my opinions and I stand behind them 100% and its based on more research than anyone has ever done on vintage steels in Gibson pickups from 1940's to late 70's. There's much about those years I just won't talk about, so I'm only giving you a purposefully vague picture, and there are definite obstacles you can't get over and reproduce vintage stock. You can do alot with off the stock alloys made these days, on that I will agree, but even there every plant's offerings are just as different, maybe more, than what magnet manufacturers offer. My guy hooked me up with a good source and just coincidentally my last big batch of keeper stock is at least a carbon match for PAF keepers and excellent stuff you just can't get anywhere. Its all hit and miss, and its why I personally cut and machine my own stuff so I know exactly how each batch sounds and where to use it. Yes it is ridiculous the extent I went to in learning this stuff, thats for sure, most of it wasn't fun, running into seeming dead-end obstacles many times with alot of lost sleep agonizing over this stuff. I am soooooooo glad its done....

[belwar]

Stewmac knows Keiyo because of me. I was their hookup in 2003 because of Allparts problems keeping parts in stock. Spent spent every night from '98 till that day searching to find out who the manufacturer of those bobbins was.
Gavitt, also came from my research..I told Jason.....not sure where Don got it though. Nobody knew of them before. I believe it was 2002 when I found them.


By the way, I found several employees of HPI tonight and have set contact in motion. The original founder may still be alive...at around 100 years old.

Then wolfe, I stand humbly corrected - I had no idea that was the case. That was a nice read to see you sharing that info back then. Well done sir!

bel.

[belwar]

Sorry Jon, I disagree, those old guys don't remember precise technical details of actually smelting and processing the steel to final stock, the stuff we found out isn't in any book and the old guy at the plant was more helpful in pointing out what was wrong with a particular bad batch of steel that made the original VL set suddenly go way wrong. In fact, that disaster pushed me into questioning everything I thought I knew at that point and starting over literally from scratch is when I learned the most valuable information. The guy who helped me was just as curious as I was and surprised at what we found. If you want to think talking to some old timer is going to get you anywhere I'd bet against it. They can't tell you minute details that went down then and you can only know by examining real examples.

I had access to an old timer who worked at Gibson during PAF days and he literally knew nothing about steel and told me to go buy ten penny nails and it'd be good. I don't quite understand your resistance to knowing there's a deeper story, you know me, personally I kept asking questions and more questions even when I thought I was done. Then something would come up and more questions would appear. It took most of 5 years just on that subject alone to run out real data and details on how stuff was made in great detail. You would literally have to own a steel smelting and cold processing plant to get closer and unfortunately they don't smelt steel the way they used to, so you don't find an abundance of certain chemicals back then due to how they did that process. The best you could do is find some 50's steel and it would have to be in those particular sizes, you couldn't just cut larger stock up and get the same results. These are my opinions and I stand behind them 100% and its based on more research than anyone has ever done on vintage steels in Gibson pickups from 1940's to late 70's. There's much about those years I just won't talk about, so I'm only giving you a purposefully vague picture, and there are definite obstacles you can't get over and reproduce vintage stock. You can do alot with off the stock alloys made these days, on that I will agree, but even there every plant's offerings are just as different, maybe more, than what magnet manufacturers offer. My guy hooked me up with a good source and just coincidentally my last big batch of keeper stock is at least a carbon match for PAF keepers and excellent stuff you just can't get anywhere. Its all hit and miss, and its why I personally cut and machine my own stuff so I know exactly how each batch sounds and where to use it. Yes it is ridiculous the extent I went to in learning this stuff, thats for sure, most of it wasn't fun, running into seeming dead-end obstacles many times with alot of lost sleep agonizing over this stuff. I am soooooooo glad its done....

So Dave - I ask this in all honesty without any insult meant ... What good does it do to know these metalugical details, when there is nothing that you can do about it today? You are still bound by steel standards that we all face. You are limited to the same copper that any of us have access to?

If you are saying that you provide a specific temper or anneal to your humbucker parts, THAT is a valid marketing point and is something that you can say "I think this makes a big difference, and this is what seperates me from the other makers".

I don't see a reason you couldn't share more of your research (Without specifics hardnesses, or compounds, or whatever) or at least the concepts that you are going after.. i.e. I dont think it harms your business to say that "Old copper appears to have different resistivity, and so I do this to get around it" or old slugs were "Work hardened" and I feel its important so I match it. By explaining it, you give yourself credibility - Particularly if you are right.

[Fuzzy Logic]

So Dave - I ask this in all honesty without any insult meant ... What good does it do to know these metalugical details, when there is nothing that you can do about it today? You are still bound by steel standards that we all face. You are limited to the same copper that any of us have access to?

If you are saying that you provide a specific temper or anneal to your humbucker parts, THAT is a valid marketing point and is something that you can say "I think this makes a big difference, and this is what seperates me from the other makers".

I don't see a reason you couldn't share more of your research (Without specifics hardnesses, or compounds, or whatever) or at least the concepts that you are going after.. i.e. I dont think it harms your business to say that "Old copper appears to have different resistivity, and so I do this to get around it" or old slugs were "Work hardened" and I feel its important so I match it. By explaining it, you give yourself credibility - Particularly if you are right.

Hello, this would be my first post here. The last few months I have enjoyed reading a lot of the postings here and fwiw, here is my take on this "old" versus "modern" copper wire debate.

"Old" copper wire does not appear to have had a different resistivity than "modern" copper wire. That is, from a standards point of view.

US Bureau of National Standards - Circular 31 - Copper wire tables - 4th edition - 1956/01/27:

Table 5, Wire table, standard annealed copper, values at @ degrees celcius: AWG 42 --> 1660 Ohm/1000 feet.
(DCR based on resistivity of 10.371,2 ohms per circular mil foot @ 20 degrees celcius)


US Bureau of National Standards - Handbook 100 - Copper wire tables - 1966/02/21:

Table 5, Wire table, standard annealed copper, values at @ degrees celcius: AWG 42 --> 1660 Ohm/1000 feet.
(DCR based on resistivity of 10.371,2 ohms per circular mil foot @ 20 degrees celcius)


The MWS website (as an example) specifies for AWG 42: 1659 Ohms/1000 feet
(DCR based on resistivity of 10.371 ohms per circular mil foot @ 20 degrees celcius (100% IACS Conductivity)).

Also the density of copper apparently has not changed during the years, both circulars mention a density of 8.89 g/cubic cm.
NEMA MW 1000 still states the same value for the density of copper.

Having said this, the chemical composition of copper wire has changed over the years (mainly to achieve an improvement of purity) so "modern" wire differs from "old" copper wire in that respect. But the resistivity does not appear to have changed over the years.

BTW; a statement that a sample of copper wire has a certain value of Ohms/foot can not be interpreted correctly without mentioning the associated diameter of the sample of bare copper wire.

As an example, a resistivity of 1876 Ohms/1000 feet would indicate a bare copper wire diameter of 0.0023515 inch (AWG 42.5, exactly in the middle of min-nom). If the diameter of this specific bare copper wire would be different than this value at this specific value of Ohms/1000 feet, then yes, the wire would be different from the standardized (and modern) wire. If not, the copper wire would just be standard AWG 42.5 min-nom wire.

[JGundry]

Dave,

This is how slugs were made in the 50's and I made them the same way. A 1215 wire order is made and the wire is draw and straightened from a coil. It goes to a machine shop who then does the simple task of setting up a Brown and Sharpe screw machine to cut them off. Then they are run. These machines have been around since the early 1900's. Then they are sent off for barrel nickel plating. Done. No mystery hidden process. The work hardening is in the process of manufacturing. That is why it is called work hardening.

Frankly I'm shocked that you would pull out work hardening of slugs as an important detail you duplicate since it is just a no brainer part of the process. It is a bit thin when it comes to compelling vintage details IMHO.

[David Schwab]

I had access to an old timer who worked at Gibson during PAF days and he literally knew nothing about steel and told me to go buy ten penny nails and it'd be good.

Dave, don't you see that the reason for that is when they built those pickups they used whatever common grade of steel they got. Steel was steel. They ordered screws and what ever easily worked plate steel for the keepers. The grade of steel wasn't part of the design, it just had to be magnetic.

Now people realize that it affects the tone, but Gibson didn't care as long as the pickup worked. That's why they were so lax about the number of turns on the bobbins.

[JGundry]

Dave, don't you see that the reason for that is when they built those pickups they used whatever common grade of steel they got. Steel was steel. They ordered screws and what ever easily worked plate steel for the keepers. The grade of steel wasn't part of the design, it just had to be magnetic.

Now people realize that it affects the tone, but Gibson didn't care as long as the pickup worked. That's why they were so lax about the number of turns on the bobbins.

You are correct. In fact I talked to an old Gibson employee about the spec. for keeper bars and he said cold rolled steel. Any consistency they had with these parts was probably due to the supplier and not Gibson. And I know they changed suppliers through the Paf era.

[SKATTERBRANE]

All Parts baseplates will "work" with a T-Top but they are not correct. They are slightly off and if you want the cover to fit properly you are way better off with the correct spacing if you are repairing a vintage pickup.

Are they all not 1-15/16" spacing (49.2mm)? I have put new Gibson covers on T-Tops, I have put new Gibson covers on my pickups with AllParts backing plates, I have put PAF repro covers on various pickups. Everything seemed to line up just fine. I did have a short period where I used some other backing plate (don't remember where I got them) and they were not exactly 1-15/16" so they did not work well with covers.

Are you saying T-Top backing plates have a different spacing than PAFs, Shaws, 57 Classics, 490R, 496R and Bursbuckers and Allparts backing plates?

I realize the outer perimeter measurement varies with different era/brand backing plates, as do various era/brand of covers. some combinations are a VERY tight fit, others are too loose.

[belwar]

Are they all not 1-15/16" spacing (49.2mm)? I have put new Gibson covers on T-Tops, I have put new Gibson covers on my pickups with AllParts backing plates, I have put PAF repro covers on various pickups. Everything seemed to line up just fine. I did have a short period where I used some other backing plate (don't remember where I got them) and they were not exactly 1-15/16" so they did not work well with covers.

Are you saying T-Top backing plates have a different spacing than PAFs, Shaws, 57 Classics, 490R, 496R and Bursbuckers and Allparts backing plates?

I realize the outer perimeter measurement varies with different era/brand backing plates, as do various era/brand of covers. some combinations are a VERY tight fit, others are too loose.

Correct me if I am wrong, but I believe the allparts products are advertised as 49.2, but are actually more like 49.45

[SKATTERBRANE]

I guess it is possible, I left my micometer in my other suit pocket!

[belwar]

I guess it is possible, I left my micometer in my other suit pocket!

Thats what she said!

[WolfeMacleod]

No problem Bel, I can be a little smug some times. =)

[Reza]

Hi all. I'm not a builder, but an avid guitarist and scientist.

First off, I love how much you guys are getting into the details on these pickups to try and create all of the elusive holy grail tones. It is awesome that you're all so passionate about your crafts.

Secondly, just wanted to pipe in that as I scientist for Dow I know we make 'butyrate plastic'... which I believe is just cellulose acetate butyrate plastic, right? I wonder if we are supplying this to mojotone through some sort of distribution? We don't sell anything in small volumes so I assume it is through some distribution. If you don't want a tank car worth of something, we pass on it!

Very interesting post. Cheers! :-)