Bruce, do you have any closeup shots that would show how this works and would you be willing to share?
I understand the gist of the concept,b can't picture the details of how you pulled this off.
Also, was wondering how the oscillating mechanism from a house fan might be able to be modified to accomplish something like this.
One destroyed house fan later,..... I don't think I can make that work.
Sorry it took a while to get back to you on this.....I took some fresh pictures and marked them up.
My coil winder is complicated looking, but the operation is really very simple. I built many of the parts of it from metal, because I have the machinery here to do that. But you could build a version of this machine from mostly wooden frame parts. A few lathe-turned metal pieces.
Here are the main parts: The spindle shaft is driven by the motor on the left, and the face plate, where the bobbin mounts, is on the right.
The large aluminum feed plate moves slowly side to side, driven by the leadscrew assembly below. On the left is a toothed belt drive which turns the leadscrew at exactly 1:16 ratio to the spindle speed. Another toothed belt drives the mechanical rotary counter at 1:1 with the spindle.
Here's the leadscrew assembly. The leadscrew itself is turned from steel, on a lathe. It has 1"-20tpi Left Hand threads on the left end and 1"-20tpi Right Hand threads on the right end. The center section is a smooth polished cylinder. The black thing in the middle of the leadscrew is a block of Delrin, which is bolted to the aluminum feed plate.
The leadscrew spins within the Delrin block, and the block also slides side to side on the leadscrew, driving the feed plate side to side. The leadscrew stays still, spinning in the two bearings on either end. The whole feed plate assembly moves left and right, riding on the leadscrew.
Under the leadscrew is the drive bar. It's attached to the bottom of the Delrin block on a pivot pin at the center. At each end of the drive bar is a small brass tooth which can engage the threads on the leadscrew. A link at one end connects the drive bar to the wooden control bar underneath. The control bar is also mounted on a center pivot, and rocks left and right through a small angle. Rocking the control bar pulls on the link, which rocks the drive bar.
Here's a close up of the brass tooth on the end of the drive bar. When it comes up and engages the threads of the leadscrew, it pulls the whole feed plate sideways. At a steady, precise rate.
Pressing down lightly on the right side of the control bar raises the left end of the drive bar, engaging the tooth, and causing the mechanism to feed to the left.
Pressing on the left side of the control bar makes it feed to the right. With no pressure on either side, neither tooth is engaged and it doesn't feed either way.
Attached to the feed plate is a horizontal steel shaft, with a Delrin wheel at the end. The magnet wire feeds off the spool, through the tensioner, around the underside of the Delrin wheel, and up onto the bobbin. I built the wheel into the machine to make sure that the magnet wire doesn't get tightly bent or rubbed in its path from the spool to the bobbin. The Delrin wheel has a deep V-groove around its edge, and it spins freely on the shaft.
Here the wheel has moved most of the way to the right.
And here it has moved most of the way to the left. The feed bar can be adjusted in position on the plate, to bring the wheel up close to whatever size bobbin I'm winding.
The whole point of this mechanism is that it provides a constant
feed rate. With every revolution of the spindle, the feed wheel moves sideways exactly 0.0031". It's always that same 0.0031"/rev at any rpm that the spindle is running. That 0.0031" feed rate is a product of the 1:16 belt drive ratio, and the 20 tpi threads on the leadscrew. Why did I make it 0.0031"? Because magnet wire in the 40awg to 42awg range is all right around....0.0022" to 0.0030" diameter. My machine is designed to do tight, even winds, putting each wire wrap in close against the previous wrap. Like a screw thread. That's intentional.
This machine basically has a fixed feed rate. It always feeds the wire at a constant rate, left or right, any spindle speed. My hand on the control bar simply changes the direction of the feed, left or right, instantly.
That's why I call this a semi-automatic coil winder. While I'm winding a coil, I'm watching it carefully, and reversing the direction when the wraps reach the bobbin flange on either side. I watch to get an even buildup, and I can easily do a little back-and-forth to build up any low spot that I see.
If I wanted to go to a faster feed rate, I'd have to change the toothed pulleys in the belt drive. Which I could do, if I ever want to. But I haven't seen any need to so far. I design all of my pickups to be tight-wound, compact coils. I'm not into sloppy scatter-wound coils.
I designed and built this machine in 2004, and it's worked very well for me. I've used it to wind the pickups for every bass I've built since then. It's allowed me to push farther into Hi-Fi type pickups, and other obscure types.
This machine is bigger and more complicated than it needs to be. Back then, I wanted it to be very flexible and capable of winding all sizes of bobbins. Now, I understand better what sizes of bobbins I'll be working with.
I recently acquired a cute little antique variable speed motor rig that's just itching to be made into a cool machine. I may build a smaller simpler coil winder from it, sized for my standard bobbin sizes. It would be a similar leadscrew feed mechanism.
