Coil is Warping / Deforming the Forbon Fiber

[verhoevenc]

So I promised I searched (even with the added power of Google) but I couldn't find an answer to this. I just wound the Jaguar-style pickups for a guitar I'm building (still a way's off but I had nothing else to do tonight). This is my first time doing single coils and using vulcanized fiber. I was pretty happy with things until I pulled the pickup off and really got a look at it! Turns out the windings have warped the top (thinner) forbon!? It's worse at the edge by the outer-most magnets, which I'd expect. But I'm more concerned about:
1- Why did this happen?
2- How can I avoid it in the future?
3- Can this be fixed or is it a rewind?
4- Should I be concerned that it's pushed it so much that at the edges tape is no longer covering my magnets inside?
5- If this is a must rewind should I expect to be able to reuse this bobbin, or is it toasted?

Specs in case they're needed: Mojotone Jaguar kit with 8560 winds of 42AWG SPN.
Also, I should mention that the forbin fit tightly on the magnets (had to ream a bit, but they finally hammered in) and they were superglued with thin CA.

Here it is in silhouette. As you can see one side pushes up more than the other. Taking both sides into account though, there is a 1/32" dip at the center of the bobbin.

Here it is with the straight edge of the other bobbin placed against it to give a nice reference to just how curved it became. Once again, 1/32" at the center.

Thanks in advance,
Chris

[verhoevenc]

And of course now... 5 minutes later, I finally find the term "flaring." Gunna read it all, but still looking for opinions and answers to the above regardless.
Chris

[big_teee]

Hi Chris:
Flaring is usually caused by too much tension.
Also you can narrow the stops on your winder, that will help.
Another thing is to Lacquer dip, or super glue the forbon to the magnets before winding.
Here's the sequence I use for SCs. Everyone does it a little different.
Bevel and install the magnets.
Super glue the magnets, and set on something warm to harden the glue.
Spray lacquer the Pickup and let dry.
Tape the magnets, then wind.
Wax Pot.
Maybe others have some additional ideas.
Good Luck,
T

[verhoevenc]

That's what I ended up gathering once I discovered the term 'flare.' Oddly, I did everything you do, in that order, except the spraying. I guess I'll try that. I did stumble upon the thread where Jason said that it wasn't good for shielding the wire from the magnets, but I have tape there anyways and double protection can't hurt!
I think the funniest thing is the largest flare reference I can find on here so far is 10-15 thousandths... and noobs generally under-tension from what I understand. How, on my 3rd pickup did I tension it so hardcore?!
Chris

[David King]

I'm betting you didn't leave a little gap .025" or so between where the wire guides are set and where the flatwork starts. The tension is secondary to piling on the wire right up against the flatwork.

[Peter Naglitsch]

Now get the exacto out, cut the wire away, super glue the flatwork in place, adjust the guides and get a pickup done so we can finaly see that wounderfuly wacky textile clad Jag finished.



On a more serious note there is one other solution and that is to use a tail stock winder that hold the flatwork in place as you wind. I wold still use super glue as an insurance as I would expect the coil to flair a bit as soon as I got the coil out of the winder. Even though I think that it at least wouldn't be as bad as on a more traditional/low end/DIY winder

[kayakerca]

That's what I ended up gathering once I discovered the term 'flare.' Oddly, I did everything you do, in that order, except the spraying. I guess I'll try that. I did stumble upon the thread where Jason said that it wasn't good for shielding the wire from the magnets, but I have tape there anyways and double protection can't hurt!
I think the funniest thing is the largest flare reference I can find on here so far is 10-15 thousandths... and noobs generally under-tension from what I understand. How, on my 3rd pickup did I tension it so hardcore?!
Chris

Beyond tension, how "tight" the flatwork is to the magnets will affect how much winding on the wire can flare out the forbin. If you use an arbor press with a jig that is the same dimension as the top flatwork (hole spacing and size), it will be a "real" tight fit and less subject to flaring. I you hammer it on with a block of acrylic or wood with the bobbin height spacing supported loosely, the fit will be much looser. Also, how the bobbin is mounted on the winder will affect flaring potential as well. If the bobbin is held in with aluminum plates, top and bottom, there will be less opportunity to flare than if the bobbin is just double back taped to a faceplate.

Here is the bobbin jig I use to build my Strat p/u's with. With the spacer section between the top and bottom, the magnets press in perfectly tight and straight. And with the top jig sets over the brass lineup pins and under the arbor press it goes once again. These types of jigs really make a bobbin that is held together "real" tight!

[verhoevenc]

Peter, quit bein' so sneaky! Also, she's still a LONG way off from being done I've been trying to clear my backlog instead of work new projects. But with the cold in the shop, sometimes it's nicer to just come in and wind.

So by no means did I leave ANY gap. I adjusted the guides until the wire way laying right at the edge. That's good to know that a little spacing is to be desired. I thought it would create loose, feedbacky, messes at the top and bottom if you left a gap for the wire to fill in a bit. Granted, I guess this is a tiny amount.

I did hammer fit these bobbins. Looks like I need to make some pressing jigs in the future? Cause with the hammer in method I DEFINITELY had to ream the holes a little bit when the flatwork came from mojotone before I could get the magnets to even THINK about going in.
Hopefully try it with a gap, and lacquer, tonight or tomorrow,
Chris

[copperheadroads]

No one mentioned anything about beveling the magnets ...........huh

[kayakerca]

I did hammer fit these bobbins. Looks like I need to make some pressing jigs in the future? Cause with the hammer in method I DEFINITELY had to ream the holes a little bit when the flatwork came from mojotone before I could get the magnets to even THINK about going in.

Chris

Bevel or no bevel, with a tight precision jig and an arbor press, those magnets slide in like a hot knife through butter! Without that, beveling is just plain good thinking.

[copperheadroads]

A slight bevel (which is hardly noticeable ) usually prevent any of the top forbon from being removed when pressing with an arbor press
The less little half moon pieces of forbon removed when pressing the tighter the fit & possibly = less flaring

[Peter Naglitsch]

Peter, quit bein' so sneaky!
Chris

LOL Sneaky Pete is going to be my new name now. Couldn't resist posting that pic. I've seen your build thread on the PG forum and assumed it was the same guitar.

[verhoevenc]

OK, this is officially going to drive me insane! I did EVERYTHING folks have said. Lacquer seal, tape (I know these aren't for the flaring, but still), set my guides a little in (actually more than ya'll recommended), tried to consciously wind less tensioned. I checked every 1000 turns or so and had only the slightest flare (read: see light if you put a straight edge across the top) by the time I hit 5000. So I went ahead and continued to 9000 (my goal). Sure enough, I pull it off and I've got just as much flare as last time if not more?!?!?!?!?!?!?!?!?! What in the word is going on here!??!!?!? I even tried winding at higher speeds as I've heard that faster speeds are harder to tension well and figured that might help too.
Nothing seems to work. It's making me want to wind only humbuckers!
Chris

Edit: I'm starting to think that maybe my reaming to get the magnets in was too much and there's just not enough hold on those outer mags. If that's the case I guess I can wind these up and use them in an application where I don't want pickup covers (which wouldn't sit right). I guess I'll test my theory tomorrow and wind one of the kit bobbins from mojotone and the other jaguar one I did.

[David King]

Could it just be the forbon warping due to sudden humidity change? The stuff is notoriously unstable. I use thin CA and let that run around each magnet where it comes through the forbon and then a layer of tape that comes right to the edge. Try thin wool gloves if you hand tension.

[verhoevenc]

It's definitely not a humidity thing. This second wind is the same bobbin I did the first time. When I pulled the windings off you could easily tape the flare back down and it'd stay. Also, I think I said this before, but by all means were these magnets CA'd too. I'll give some thin wool gloves a try but I have a hard time believing I'm just THAT hardcore at tensioning hahaha.
Chris