Auto Winder

[John_H]

I built this auto winder using the level wind mechanism from a spinning reel. It's fully synchronized with variable pitch. I just got it together, and I've only wound a couple of coils, but it seems to work great. I've got less than $25 in the project.

[copperheadroads]

That thing looks great

[John_H]

That thing looks great

Thanks, I didn't give much thought to the aesthetics. I concentrated mostly on function, and size.

I started thinking about an automatic winder when I built my hand guided machine several years ago. I researched a CNC solution, and I've read hundreds of posts to see what everyone else has come up with. It seemed that the electronic winders were quite complicated, and expensive, so I opted for a mechanical solution. Anyone who's ever tried to make one knows that the biggest obstacle is synchronizing the traverse with the platen, and making the TPL, and length of the traverse adjustable. I was able to achieve both pretty easily.

Here are a few gut shots..

The first picture shows a 6:1 friction drive that tames the sewing machine motor. Unladen it runs at ~1900rpm after the reduction.


In this picture you can see the counter wheel, and switch.


The 6" alum wheel that drives the reel is from an old dead disc sander. It's also on a friction drive at a 1:12 ratio. The reel is movable which makes the pitch variable. By moving the location of where the tire on the reel contacts the disc adjusts the TPL, and keeps things in sync. Also pictured is the wire guide, and tensioner. The wire guide is adjustable along the length of the follower that it's mounted to. The length of the traverse is easily changed. There's a ceramic bead that guides the wire. It's a simple felt tensioner.


This shows the slider that the reel is mounted upon.


Although I've thought about it for years, I put it together in a few hours. It all works much better than I expected.

[Jim Darr]

Very clever design…congrats!!! Thanks for the detailed pics.

[David King]

John, I love the friction design. It saves so much time, effort and expense over pulleys and belts or gears.
Also your throw reduction for the traverse is brilliant. My only question is how the wire piles up at the top and bottom of the coils (or not).

[John_H]

Very clever design…congrats!!! Thanks for the detailed pics.

Thanks Jim, I'm happy to share.

John, I love the friction design. It saves so much time, effort and expense over pulleys and belts or gears.
Also your throw reduction for the traverse is brilliant. My only question is how the wire piles up at the top and bottom of the coils (or not).

Thanks David. For exactly the reasons you stated I used a friction drive on my original winder for the mainshaft, and the decade wheel on the counter. Pulleys and belts are difficult to get, and expensive. Meanwhile a 1/4" ID piece of fuel hose pushed over the shaft of a sewing machine motor makes a perfectly serviceable capstan that will drive about anything that is round. It just makes sense if you're trying to keep your costs down. I didn't use any precision bearings on this. Instead I used bronze bushings that I salvaged from a reel to reel. The platen is made from the flywheel of the same tape deck. To hold things in place (in lieu of expensive locking rings) I cemented rubber grommets to the shaft behind brass washers that act as thrust bushings. It all runs very smooth.

The cable driven adjustable traverse was an idea that I had a while ago. I love it when the solution is simple like that.

I wound some humbucker coils with it last night. I found that if the coil is piling up on the ends, you can correct it by shortening the traverse. I can see in my short term experience with it that devising a reliable tensioner might be the most difficult aspect of all.

[Jim Darr]

John,

Here is an idea for tensioning --- I assume your magnet wire spool is on the floor and you’re tensioning near the spool as well. Add another ceramic eyelet to the other end of the traverse arm/rod, or after your pictured felt tensioner and existing eylet. Then place an additional felt tensioner between the two eyelets. You’ll still be able to move the eyelet closest to the bobbin for changes in coil height. All my cam winders are set up with at least two felt tensioners and I get excellent results. Be careful not to apply too much pressure/tension on the wire with the felt tensioner. I can confidently wind up to 46 gauge without troublesome breakage using a similar technique. I use a custom designed (homemade) overhead dereeler which also incorporates ceramic fishing rod guides.

Another thought is to create templates on the machine for TPL and coil height adjustments. You could mark them on the wood directly or make some type of plate. I’m assuming you will wind many different pickups on this machine. The templates will reduce the trial and error when you change bobbin geometry. I have most of my machines set up for a specific pickup and wind pattern, but have two that I use for general winding/prototyping and I know how long it takes to reset each machine for a different pickup/wind pattern and how extremely frustrating the process can be.

Hope this is helpful.

[Hugh Evans]

Brilliant work, it's always a pleasure to see ingenious mechanical solutions like this.

As for tension control, why not go with a simple dancer arm? You can create a nice simple friction based pinch roller using a couple of urethane skateboard wheels if you want to be a little fancier than felt between a couple of washers and a wingnut. Using Hooke's law you can even calibrate the tension, or go so far as to synchronize it with the bobbin to maintain constant tension with minimal variation. Either way I will definitely be following along, this is a great design.

[John_H]

John,

Here is an idea for tensioning --- I assume your magnet wire spool is on the floor and you’re tensioning near the spool as well. Add another ceramic eyelet to the other end of the traverse arm/rod, or after your pictured felt tensioner and existing eylet. Then place an additional felt tensioner between the two eyelets. You’ll still be able to move the eyelet closest to the bobbin for changes in coil height. All my cam winders are set up with at least two felt tensioners and I get excellent results.

I've been mounting my wire spool on a mic stand , and letting it de-reel to the single felt tensioner. I had already planned to try multiple's, so I like what you said there confirming my assumptions. I don't want to put any more of a load on the traveller, but I can easily build a different, larger piece that would accommodate more tensioners in sequence.

Be careful not to apply too much pressure/tension on the wire with the felt tensioner. I can confidently wind up to 46 gauge without troublesome breakage using a similar technique. I use a custom designed (homemade) overhead dereeler which also incorporates ceramic fishing rod guides.

I need to find a better method for de-reeling. I've got a couple of ideas. This will add a small amount of tension also. I hadn't thought about overhead. hmmm...

Another thought is to create templates on the machine for TPL and coil height adjustments. You could mark them on the wood directly or make some type of plate. I’m assuming you will wind many different pickups on this machine. The templates will reduce the trial and error when you change bobbin geometry. I have most of my machines set up for a specific pickup and wind pattern, but have two that I use for general winding/prototyping and I know how long it takes to reset each machine for a different pickup/wind pattern and how extremely frustrating the process can be.

I've already got a few reference marks on it. Once I have the center of the pivot aligned with the center of the bobbin it's not too difficult. If that's off center, the bias will affect the shape of the coil.

Hope this is helpful.

Thanks for all of the input Jim

[Chris Turner]

I've been mounting my wire spool on a mic stand , and letting it de-reel to the single felt tensioner. I had already planned to try multiple's, so I like what you said there confirming my assumptions. I don't want to put any more of a load on the traveller, but I can easily build a different, larger piece that would accommodate more tensioners in sequence. I need to find a better method for de-reeling. I've got a couple of ideas. This will add a small amount of tension also. I hadn't thought about overhead. hmmm...
I've already got a few reference marks on it. Once I have the center of the pivot aligned with the center of the bobbin it's not too difficult. If that's off center, the bias will affect the shape of the coil.

Thanks for all of the input Jim

John, awesome work! Love it. Thanks for sharing the pics!


A couple questions, if you don't mind:
1) What diameter is the main drive shaft?
2) Where did you find the wheel that fits up against the sewing machine motor's shaft? Almost looks like a shopping cart wheel...

Thanks in advance.

[John_H]

Brilliant work, it's always a pleasure to see ingenious mechanical solutions like this.

As for tension control, why not go with a simple dancer arm? You can create a nice simple friction based pinch roller using a couple of urethane skateboard wheels if you want to be a little fancier than felt between a couple of washers and a wingnut. Using Hooke's law you can even calibrate the tension, or go so far as to synchronize it with the bobbin to maintain constant tension with minimal variation. Either way I will definitely be following along, this is a great design.

Thanks for your ideas Hugh. I'm not ruling out any options at this point. I'd like to keep things simple, but it has to have some measure of reliability.

John, awesome work! Love it. Thanks for sharing the pics!


A couple questions, if you don't mind:
1) What diameter is the main drive shaft?
2) Where did you find the wheel that fits up against the sewing machine motor's shaft? Almost looks like a shopping cart wheel...

Thanks in advance.

Thanks Chris, the main shaft is 1/4 inch, and the wheel I cannibalized from a caster I bought at Lowes. It was one of my major expenses. Something like four dollars.

[John_H]

Here's what I'm working on now.

I ground the little C clamp down so that it would lie flush on the frame, drilled it, and attached it with screws. Those are common adhesive felt pads. The dancer is made from a guitar string.

[Lyrebird Steve]

The dancer is made from a guitar string.

... that is awesome, will be adding to mine

[John_H]

... that is awesome, will be adding to mine

It seems to work well. I polished the eyelet so that it wouldn't abrade the wire. If you leave the length adjustable, you can fine tune so it will oscillate with the rotation of the bobbin. Just being able to "see" the tension is a big plus.

[John_H]

I've finished wiring everything permanently, and I've added a pigtail for hooking up the freq. counter on my multimeter. This will help my consistency by keeping accurate rpm data. The tensioner is working well. I've been experimenting, and have been able to wind some decent looking coils. I plan on building another traverse. It will be the same with the exceptions of having the pivot point outboard, and being a little larger. This will move the wire guide farther away from the coil, and reverse and lengthen the arc that it travels on. I'd like to see if this has any effect on the shape of the coil.