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# Looking for help with making a coils Answered

I am wanting to make a rodin coil, like the second picture I included, except I don't have a 3D printer and I don't necessarily feel like dropping \$200 on buying one and learning how to use it just to make a coil. So I'm asking if anybody would want to 3D print, ABS is fine, a Rodin coil for me? I have a PayPal account so we could work out a mutually agreed-upon price and I'll pay for shipping. I will also cover the the shipping cost. 76five, for6O, fourOsix9 shoot me a text ( that's my Google Voice number obviously I wouldn't give out my real cell phone number LOL)

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After another thought it might be good to give some additional info on the general design of these rodin coils.
It might help you and others to understand some points that need to be considered:

The idea behind such designs is to create a magnectic field with some unique properties.
One key design element is that all needs to be even and uniform.
If you would look into the donut in the second pic above you would see that the Litz wire is touching on the inside, while there is some spacing on the outside of the donut.
The number of turns or better spirals in either direction should always be part of the Fibonacci sequence.
All this means that your minor donut diameter is determinded by the wire diameter AND how many turns you need to make to comple the sequence.
The major diameter should be such that the wire spacing on the outside is not more than three times the wire diameter.

To calculate these values requires a quite decent understanding of geometry and how to simplify the calculations.
For example:
If you want 34 turns on the first round of winding (the inner cage) then you could see these as a piece of pipe that needs to fit into the donut.
Wire diameter times 34 equals the central diameter LENGTH of the pipe.
From this length you can use basic formulas to get the radius or actual diameter.
Add the wire diameter once more and you get the outer diameter of such an imaginary pipe.
With a few mm extra you should have enough room now for your 35 windings.
A good way of guesstimation to find the right ring diameter for your donut is to multiply the minor diameter by 2 to 2.5.
All this can not be too small though; That is why the pipe imagination for the windings helps.
For most beginners it is really hard to find the right distance between inner and outer coils.
Same for how many turns to use.
So keep the fibonacci sequence in mind ;)
In this example you would want 55 turns or spirals on the outer winding.
And by knowing this already you can use the same math to get the diameters you need ;)

Of course people not always stick to the Fibonacci or other natural sequences to design their coils - it is still all expimental after all....
In any case you should base your calculations so that on the inner diameter the wres are basically touching.
To increase some coil properties builders often aim to use winding numbers that allow for an even spacing.
So the only add a few turns to make the inner parts of the windings touch each other.
Other builders aim for an even spacing between the two coils throughout - like in your 3D printed example.

Here is a little exercise trick that helps to get a feeling for the winding patterns and how to get a nice symmetry into it:
Take some nice cord, I prefer the standard paracord here.
Make a little loop and start looping the cord around this.
You will notice that when doing this really tight you get a lot of windings around but it will be very hard to keep it all under control and even.
Going quite loose however and you will see the cord offers you a direction to go, the angle is always the same.
You will also notice that you now can keep going around with your spiral turns and that you go from a single loop configuration to a double and after the next completed round to a triple.
If you starting loop was close enough to a perfect match the last round will complete the inner ring to a full and closely wound "ring".
If you try to keep the outer windings close to each other you will notice the strand pattern you also see on some rodin coil designs.
You can do this with a plastic donut or ring too and after just a few times of doing this you get a feeling for what looks right and what does not when winding.
Might save you a few hours of frustrating calculations and actual wire winding.

The spacers are pritable, not the coil itself.
The first rodin coils were just made on donut shaped plastic rings or these polystyrene rins used for artwork and dcorations.
If you really need to work with spacers as above then one option is to simply print the design out and then use a fine saw or good knife to cut it out thin chipboard or similar.

Before you worry on how to make winding tamplate you should worry about the Litz wire ;)
Even a small coil can use several meters of it...
All must match in the right dimensions too....

Check out Shapeways, a 3D printing service that ships to your door!

You can even print metals!