Title says it. Seems it would be good to know when the "neutral axis" calculation method should be used or not? Not sure where thicker wire starts on the scale of AWG, for the builds I do there seems to be about a 1 wrap difference. I get around the confusion by targeting builds in between the 2 calculations.
Whem to use "neutral axis" in Steam Engine?
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Neutral axis is simply the mandrel OD/coil ID... plus the radius (or thickness ÷ 2) of the wire. I've not encountered a circumstance where knowing the axis served a purpose.
It doesn't. really just curious... It does make a difference of 1-2 wraps on a coil when building. it's the difference between a 1.8ohm and 2.2ohm coil, in some cases. Not a big deal at those ohm range. But It could become an issue at lower OHMs. If it serves no purpose why have the check box to turn the calculation ON/OFF.
Hi. If I knew exactly what was going on, the checkbox probably wouldn't be there in the first place. 
In theory, the neutral axis (the plane of wire where there is no compression or stretching when bending) should be the ideal diameter to use. At least that is what I think/feel. And a simple way to get pretty close to the neutral axis in a symmetrical wire is by adding half of the wire thickness to the inner diameter.
In practice, using the default setting (outer diameter), usually seems to yield the most accurate result. What I mean by that is the result that matches the measured resistance more closely.
Maybe this is because the wire stretches more than it compresses, so the resistance increases compared to a non-wrapped wire. Or maybe the deformation of the wire leads to a net reduction in cross section area. Maybe metal fatigue is increasing the resistance. Maybe there are other factors at play as well or instead. I simply don't know.
So anyway, experience suggest that in everyday use, the default setting (outer diameter) will usually give you the most accurate result. Except when it doesn't. I'm sorry that I cannot give you a better answer, but the coil is an analog circuit, and there are so many factors at play that nobody (except possibly Stephen Hawking) can keep track of them all. If you click the "How it works" link in the bottom left corner of the calculator page, I have mentioned some of the error sources that I've been able to think of.
In theory, the neutral axis (the plane of wire where there is no compression or stretching when bending) should be the ideal diameter to use. At least that is what I think/feel. And a simple way to get pretty close to the neutral axis in a symmetrical wire is by adding half of the wire thickness to the inner diameter.
In practice, using the default setting (outer diameter), usually seems to yield the most accurate result. What I mean by that is the result that matches the measured resistance more closely.
Maybe this is because the wire stretches more than it compresses, so the resistance increases compared to a non-wrapped wire. Or maybe the deformation of the wire leads to a net reduction in cross section area. Maybe metal fatigue is increasing the resistance. Maybe there are other factors at play as well or instead. I simply don't know.
So anyway, experience suggest that in everyday use, the default setting (outer diameter) will usually give you the most accurate result. Except when it doesn't. I'm sorry that I cannot give you a better answer, but the coil is an analog circuit, and there are so many factors at play that nobody (except possibly Stephen Hawking) can keep track of them all.
If you click the "How it works" link in the bottom left corner of the calculator page, I have mentioned some of the error sources that I've been able to think of.Logically That is what I was thinking. My confusion over the calculation was the reality that my coils, seem to turn out closer to the Neutral axis calculation than the default.. Being that I use 29awg and thinner wire.. I was wondering the definition of "low ID" and "thick wire", I always considered me to be using rather thin gauges.
Anyway love the calculator. It gets me close enough regardless the axis calculation, that I have never built a bad coil or hurt my device. I have built many coils that didn't turn out how I expected, but never so far off that I had to tear it out and start over. I just continue on the way, I am.. Using BOTH calculations to help decide on how to build and run my Vape.
Anyway love the calculator. It gets me close enough regardless the axis calculation, that I have never built a bad coil or hurt my device. I have built many coils that didn't turn out how I expected, but never so far off that I had to tear it out and start over. I just continue on the way, I am.. Using BOTH calculations to help decide on how to build and run my Vape.
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