Dancing arms: Who has had success using them?

[shawnl]

One of the things I've found about building my own winding machine is how the tinkering and refinement never seems to end. I was proud of the fact that I build a successful working machine but when I finally got around to winding my first pickup, I just couldn't keep the wire from breaking. I have now redesigned and build a new machine that incorporates a dancing arm and have been very pleased with how much tension I can add. The dancing arm mechanism really seems to solve the problem the for me. The only issue is that it the arm seems to flail up and down a it more aggressively then I expected. I may need to use a tighter spring. Either way I was just curious about who else is using them and how much motion is considered effective? Thanks for your input.

[David King]

Shawnl,

What tension are you trying to achieve and how are you measuring the tension?

If you are breaking wire it sounds like you need to examine your wire path first. What are you using for your tensioner? How far away is the tensioner from the coil you are winding. The further away the better, 2 feet seems to work well.

Very few of us use dancer arms, they really shouldn't be necessary...

What's your arm made out of? I'd make it from the lightest materials available to minimize inertia at higher speeds. Don't hinge it, instead use the material's own modulus elasticity to be it's own spring. I'm thinking carbon fiber rod that comes as small as 1mm dia. A delrin/acetal needle "eye" at the tip should work as your wire guide.

[shawnl]

Shawnl,

What tension are you trying to achieve and how are you measuring the tension?

If you are breaking wire it sounds like you need to examine your wire path first. What are you using for your tensioner? How far away is the tensioner from the coil you are winding. The further away the better, 2 feet seems to work well.

Very few of us use dancer arms, they really shouldn't be necessary...

What's your arm made out of? I'd make it from the lightest materials available to minimize inertia at higher speeds. Don't hinge it, instead use the material's own modulus elasticity to be it's own spring. I'm thinking carbon fiber rod that comes as small as 1mm dia. A delrin/acetal needle "eye" at the tip should work as your wire guide.

Thanks David for your input! Well my original setup used a felt tensioner at the traverse that slid back and forth on rods. The idea was to create a semi-auto winder where the traverse motion would still be controlled by hand. The wire spool rested on the floor which was about 2.5 feet below my workstation. The wire then fed through a pulley system which redirected the wire direction at a 90 degree angle to a short stationary arm that could be adjusted up or down to put tension on the wire addition to the felt tensioner at the traverse mechanism. This pulley system was located about 1.5 feet away from the traverse.

In my revised setup, the wire spool rests on the same surface as the winder and is 1.5 feet away from the traverse. The wire feeds upwards about another 18 inches through a felt tensioner pad, a simplified pulley system, and then a dancer arm with a small pulley on it. The wire then goes back down to the traverse. In all the wire travels a distance of about 3 feet before reaching the the traverse. The dancer arm is made from coat hanger wire and is hinged with a spring that pulls the arm to an up position. This entire mechanism is designed to be adjustable by sliding up in down on a rod and then held in place by a set screw. The tension seems to come more from the tensioner pads below the pulleys than the position of the dancer arm. Unfortunately, I don't really have a way of measure it other than doing a simple pull test on the wire. I try to get it as tight as possible so long as the wire still pulls through the pulley system smoothly and then gently jerk the wire a few times to see if it will break.

Seems like the consensus is that dancer arms shouldn't be needed, but I have noticed a big improvement between this and my last design. So far I have only been winding at slow speeds around 500 to 700 rpms. However, I think I now realize why they will be a inertia problem at high speeds. I may have to try the fixed flexible arm method you suggest.

[David King]

Midwest Products sells small diameter CF rods and tubes at most local hobby shops. Your pulleys should to be as light as possible too, "indoor flier" wheels might be just right for that.

[copperheadroads]

Shawnl,

A delrin/acetal needle "eye" at the tip should work as your wire guide.

Hey David ,Do have a link for the needle eye .I was wondering about adding one of those to my winder

[shawnl]

Actually, I did get a lot of parts for this project at my local hobby shop. The pulleys are from one of those Tamiya model pulley sets and are most certainly very thin and lightweight. I'll have to look for those rods next time I'm there.

[Joe Gwinn]

I have now redesigned and build a new machine that incorporates a dancing arm and have been very pleased with how much tension I can add. The dancing arm mechanism really seems to solve the problem the for me. The only issue is that it the arm seems to flail up and down a it more aggressively then I expected. I may need to use a tighter spring.

It sounds like the mechanical resonance frequency of the dancer arm is too low. The solution is to make the arm both lighter and stiffer, each of which will raise the resonance frequency.

How fast are you winding, in RPM? When winding an oblong object like a pickup bobbin, you will get two pulses per revolution, so the drive frequency is twice the RPM. For instance, at 1200 RPM, you will get 2(1200/60)= 40 pulses per second.

See posting 26 in http://music-electronics-forum.com/t29885/#post265259

[David King]

I personally don't think tension is a good goal for it's own sake. All the pickups I've owned that failed, often after many years of operation, failed because they were wound too tight.
I wind at the minimum tension required for a coil that stays together. I'm always potting my coils so a little looseness isn't a problem. If I were winding coils that wouldn't get potted then I'd slow the wind way down and eliminate centripetal force pulling the wire away from the core.

[David King]

Hey David ,Do have a link for the needle eye .I was wondering about adding one of those to my winder

Copperheadroads,

I'd make one from a little chunk of acetal, there are thousands of small parts for models made from acetal and you could adapt a small pinion gear or similar from the hobby shop.
Another option would be to use one of the teflon super glue fine applicator tips as a wire guide.

[shawnl]

I personally don't think tension is a good goal for it's own sake. All the pickups I've owned that failed, often after many years of operation, failed because they were wound too tight.

It seems that most amateurs, myself included, probably think that the trademark of a quality pickup is a tightly wound coil. I was reading some posts when I first started of how people were winding too loosely and the tone sounded muddy and flat. I've been trying to make sure I don't follow the same path. So my goal has been to wind as tight as possible without stretching the wire or distorting the bobbin. I'm just curious though if you don't necessarily wind for tightness do you end up sacrificing any brightness from the tone?

[David King]

shawnl,

I think you need to keep reading or better yet start listening to your results. If you want a brighter pickup, start with fewer turns and/or use thicker insulation. Magnets will also have much more effect on tone than a tight or loose wind. That said, if your wire is looping off the edges and hanging out on all sides -that is too loose and perhaps the tone will suffer.
Some folks say that potting in soft wax does dull the tone and that is were a tight wind can be useful, the theory being that a tighter, un-potted coil will be less susceptible to feeding back at high volume and will still sound brighter than a potted pickup. I build basses and pot all my pickups so haven't tested the theory out for myself. For me, long-term reliability is job number one followed by quiet operation. Tone at the bass-end of the spectrum is so subjective and prone to hype-of-the-minute that I just aim to please myself and then adjust according to what the customer hears.

[David King]

Shawnl, you might enjoy reading Bill Lawrence's take on winding from 1996. There are undoubtedly folks here that will disagree with some part or another but I think he'll give you a radical (root) baseline for understanding all the stuff (read potential BS) you'll come across here and elsewhere.

BLOG.PICKUPOLOGY.COM: In The Beginning

[David Schwab]

There are undoubtedly folks here that will disagree with some part or another...

If a coil is perfect, the pickup will sound great. A thousand turns, more or less, have very little effect on output or sound. There is no difference between layer or scatter wound, hand or machine wound coils; or if you use enamel, Formvar or modern polyurethane coated wire, as long as the coil is perfectly wound and free of shorts.

This is pretty much my experience.

[shawnl]

After reading this article, I feel much better about my pickup making endeavor. On one of the first forums I ever posted, I pretty much got this long drawn out lecture from some electronics engineer essentially warning me that pickup making involved far more nuances than I might be prepared for. It was as though he was saying that I shouldn't expect to get great results and there's no advantage to winding my own as opposed to buying one that has been professional manufactured and properly tested for dynamic range. The bottom line is that there are certain basics to pickup making that aren't that terribly complicated. The problem is that some people think their work is the reinvention of the electric pickup.

[David Schwab]

One of the things I've found about building my own winding machine is how the tinkering and refinement never seems to end. I was proud of the fact that I build a successful working machine but when I finally got around to winding my first pickup, I just couldn't keep the wire from breaking. I have now redesigned and build a new machine that incorporates a dancing arm and have been very pleased with how much tension I can add. The dancing arm mechanism really seems to solve the problem the for me. The only issue is that it the arm seems to flail up and down a it more aggressively then I expected. I may need to use a tighter spring. Either way I was just curious about who else is using them and how much motion is considered effective? Thanks for your input.

It sounds like you are winding too fast? It's normal to break wire in the beginning until you get the feel for it.