tensioning vs. traverse... an on-going battle

[FunkyKikuchiyo]

Over the years I've been learning pickup making, I keep tweaking my setup here and there. I've only had one basic setup, but it has gone through countless revisions. I've come to a conclusion that one of the beautiful things of hand guiding is that your fingers are inconsistent, and are a tensioner and traverse control in one.

So, here's what I've encountered. If I use a rigid guide for a more mechanized traverse, as the bobbin (which is always irregularly shaped) pulls wire off of it, it pulls at varying speeds. My felt tensioner does a wonderful job with this, but my traverse setup relies on down pressure on the guide to keep the wire moving back and forth, so this ends up meaning that the wire is constantly slacking and stretching. This really seems to happen regardless of how I set my felt tensioner except on the extremes when it is totally slack or totally tight. My understanding is that this is where the old "rubber band" debate comes from of Fender lore. My motor is direct drive (an old drill motor) so I no choices to compensate at the plate, except to hope that some day I'll step up to a CNC setup where I can vary the winding speed (or maybe I shouldn't give away that idea).

Has anyone else dealt with this? I'm thinking that the bar I'm using for down-pressure on my traverse guide is the spot that needs to be fixed, but I'm not sure how. I don't know if I could possibly make it elastic without making it sloppy. Use a drinking straw instead of a metal rod? I've been scratching this spot in the back of my head raw working on this one... it is one of the last things to debug before a production run for me, and I'm hoping thinking out loud on this board will help.

Thanks!

[kev]

This situation seems similar to what I ran into as I develop my winder although, my wire guide may be a bit different than yours.

My guide is pushrod activated with a return spring but for now I am using my hand to guide it back and forth before I start designing cams. The guide I built is a clamp style but has .005 clearance between the plates. All of my tensioning is done between the spool and the start of the guide.

During my testing with two alligator clips and felt it seemed to work well but I was getting a bit more bulge in the centers than I cared for. After some thought I decided to build a delicate dancing arm to run between the two alligator clips. I built it so I can adjust the spring tension, and length of the dancing arm for leverage. I think I have less than 20 bucks and a couple hours of work in the whole thing.

Formvar wire runs beautiful but PE is going to take some tweaking if I didn't get a bad spool of wire. The PE does seem a little stickier than Formvar but I think my spool was from the end of a big spool. It coils really small as it comes off and kinks just before the first piece of felt.

My DCR on test Humbucker bobbins has been within .005 on identical turn counts. It runs very, very smooth and moves just enough to pull the slack as the bobbin reaches the slack point.

Running a clip just after the spool was paramount. If I stop the winder to inspect the coil the arm will raise and pull wire from the spool leaving a bunch of slack. With a clip at the beginning of the guide I have one tensioning adjustment while the dancing arm does what it was designed to do or I can remove the clip before the guide for a looser wind still using the arm.

Although it's in rough prototype right now I can try to snap some pics over the weekend if you are interested?

[Bruce Johnson]

Take a look at what I did with my winder:

http://music-electronics-forum.com/t10612/

I put the tensioner back behind the winder, and bring the wire up and around a narrow wheel as it feeds onto the bobbin. The wheel spins freely and the wire rests in a narrow V-groove. The traverse mechanism moves the wheel side to side.

The main point of using the wheel is that, when winding oblong bobbins, the point where the wire leaves the circumference of the wheel is free to move up and down as the bobbin rotates from wide to narrow. With a fixed-type guide, there's going to be additional drag as the wire goes through the guide at an angle. That oscillating additional drag makes it tough to get the tension even. To minimize that oscillating drag, you need to move the guide back away from the bobbin, which causes other problems. Using the wheel as the feed guide minimizes geometry and drag fluctuation problems, and allows the guide to be right up close. I can place the wheel very close to the bobbin, usually within 1/8" of the flanges. In the pictures, I'm winding a round spool bobbin, but I've used this machine to to wind 7-string bass pickups as wide as 5 1/2".

[FunkyKikuchiyo]

kev - I'm not quite following what you're saying without seeing pictures, so if you have them handy that may help!

Bruce - I have a similar setup, wherein I'm using a wheel to guide the wire, but the wheel doesn't turn freely. It is only a wheel because the traverse device itself turns (it is on a threaded rod). So, you think a bit of spin in there helps? I assume that thing must turn like crazy as you're winding?

[kev]

kev - I'm not quite following what you're saying without seeing pictures, so if you have them handy that may help!

No problem, I'll get you a pic this weekend.

[kev]

Ok, sorry for the delay. It was quite a busy weekend but I have some pics.

Please be nice. This is my first attempt at building any type of machine and as of now it is in a rough prototype state just to see if I could design and build it. It's mostly surplus parts and robbing some parts from old radio control car stuff I had floating around.

Here is how it sits now so you can see I set up everything behind the main spindle. the plastic funnel will be replaced with a wire loop shortly.



Here is my first traverse. At the moment the motor for the cam isn't mounted but will be in the top right of the picture. The cam will rest against the pushrod to activate the traverse. For now, I have been guiding it back and forth by hand while I work out tension and some other things.





Here is the dancer I built. Right now I have it clamped in a small drill press vice for mock up and testing. In the end it will be mounted and have the ability to adjust the whole assembly up and down.

Using this between my felt clips has greatly improved the situation you have and it was simple to make. I can adjust the length of the arm, the tension of the spring, and even lock it as an idler if I need too.

While operating it travels about the length of the slack from spinning an oblong bobbin. It is not aggressive, and moves quite smoothly. From my testing it has really helped keep wire in the bobbin when overwinding by eliminating the bulge on the long side.



Hope this helps spark some ideas.

[David Schwab]

Nice work!

[kev]

Nice work!

Thank you David. It has been working out a bit better than I expected.

[Jazz P Bass]

Way cool device!
How about a pic of the machine shop

[kev]

Way cool device!
How about a pic of the machine shop

Thank you.

lol, the workshop is a mess right now. It's in the basement and we had a sump pump fail which left 2 inches of water all over the place a couple weeks ago.

It isn't anything special but I am working on it and adding some more tools. I built everything using a jig saw, 12" drill press, a small sander, and a Dremel.

[copperheadroads]

Very cool -the funnel is nice touch , might have to steal that one

[kev]

Very cool -the funnel is nice touch , might have to steal that one

Feel free man. If anyone takes anything from my posting here I consider it a token of appreciation for the info others have shared.

The funnel works well but I am trying a wire loop setup right now as I fight with PE wire. No matter how I orient the spool it tends to coil real small just before the first felt clip, kink as it goes in, then break as it catches in the felt regardless of any tension settings.

Thinking I had a bad spool I tried another but still had the problem. Switching it over to the wire loop and lowering it enough to catch the wire as it unspools seems to have solved it but I need to tweak it some more. The present spools I have will coil up to a 1" diameter circle soon as it comes off the half pound spool..... Quite frustrating....I really like PE but am real antsy while I wind thinking it's going to break at any second.

[David King]

Kev you sound like the perfect candidate for the Wisker disc.
Azonic Products - Tension Devices

[FunkyKikuchiyo]

Ditto on the wisker disc - I was thinking that when I saw the picture, too.

Thanks for the pictures! If that is your idea of embarrassing machining, I'm DEFINITELY not posting pictures of MY winder! I don't think I could adapt that set up to my winder because of how the wire path works - I'd have to start from scratch.

I would like to ask how well the spring works. My fear in using a spring is that it would want to bounce at its resonant frequency which probably wouldn't align with the winding speed... if that makes sense.

I've been trying to piece something together using nylon guitar strings, but it is creating a bit of "wire curl", so I need to keep working on it. Hmmm....

[kev]

Kev you sound like the perfect candidate for the Wisker disc.
Azonic Products - Tension Devices

Yep. I saw that link on here before but haven't ordered one yet. I actually made one last weekend using some bristles I trimmed off of a broom. It had a little too much tension and made funny noises. lol

Ditto on the wisker disc - I was thinking that when I saw the picture, too.

Thanks for the pictures! If that is your idea of embarrassing machining, I'm DEFINITELY not posting pictures of MY winder! I don't think I could adapt that set up to my winder because of how the wire path works - I'd have to start from scratch.

I would like to ask how well the spring works. My fear in using a spring is that it would want to bounce at its resonant frequency which probably wouldn't align with the winding speed... if that makes sense.

I've been trying to piece something together using nylon guitar strings, but it is creating a bit of "wire curl", so I need to keep working on it. Hmmm....

No problem. I wouldn't say embarrasing. Just my first go around and it looks all pieced together. lol

The spring is from a shock absorber off of a radio control car. It is variable rate but isn't very strong. I understand the bounce at resonant frequency but it shouldn't bounce.

I designed the traverse setup so the spring always has constant tension. Once the motor and cam is mounted the spring actually pushes the assembly up against the cam or rocker if I go that route. This should avoid any bouncing, correct?