Tensioned Micro Coils. The next step.

[AllPepperS]

Take that same vice grips using it to trap the wire under your leg and pull up on it to a pin vise and you can easily get to the strain level I talk about on this thread. You're using the pivoting of both forearms on your thighs pulling up to a rotating bit and this is capable of far more than a simple weight. I use this to wind fat gauges and multi-wire. Alternatively, I get someone to just pull on it.

I'm not quite getting that picture well ah.. maybe I'm not sure the wire will stay in the jaws sideways? I'm game, seems maybe it would be easier to feel the pressure than pulling out from it. My pin vise isn't here yet but I have a reasonable facsimile I can try. So what you are saying is just plain downforce is not enough and actually might need to be even heavier to do any good

 

[MacTechVpr]

there's a problem with the search on this site since the upgrade, can't find older posts from before the upgrade searching older threads, I just searched for "newton" in that thread with no hits... I'd love to see some of the science behind this

Straining to find Newtons...

Well I looked too. Thought I had brought over this particular post on SxD's original microcoil thread when this issue was first brought up by @SLIPPY_EEL…

It's my understanding that a firm man's grip may equal 300 Newton's. I think the above photo of a Vernier Dynomometer (grip strain meter) is illustrative of what I'm talking about. Marginal (turn-to-turn) adhesion on a wind directly from a spool to a mandrel occurs somewhere above 275 Newton. Very difficult to achieve or sustain with any control using a standard hand over hand wind. However, multiplying that force very slightly with wrist tension and adding some forcing of rotation to shape the wind is very easy to accomplish. And even a child has enough combined hand force with two hands to achieve it. So control is very sustainable and the effort can be accomplished quicky and directly the very first time.

The point I was making is that you can't simply use thumb-and-finger pressure (which is substantially less than grip strength). Considering grip and wrist strength, finger and forearm pressure gives us a formidable combined force if you use the right tool/s and pivot point/s for leverage and control. In other words…why struggle? A few estimates I've done with folks more knowledgeable convinced me that the force required to achieve wire adhesion for even thin gauges is pretty high. I've seen pretty strong guys miss the mark pulling with pliers. Others, got it with strong hand pressure. These were tests to see what could be done without leverage. Those experiments more than emphasized how important consistency is to applying strain for the coherence of the coil.

Straight hanging weight may serve as a workable individual solution but I think one has to consider other factors alongside the mass, e.g. the down force of air pressure/sq in., for any meaningful comparison to a standard like foot pounds or Nm. And there is no standard for the kinds of weights that we might use. So that makes it problematical as an index. I considered all these factors which led me increasingly to the idea that the simplest indexing tool is sitting right behind our eyeballs. And our individual capacity to discern strain probably as good or better than any strain gauge we're any one of us likely to afford. All this turbo led me increasingly towards the conclusion that the old industry standard, the pin vise, was an elegant solution even as I strongly believed the public wouldn't spend 5$ for one.

A weight index will work as a guide. A little finger pressure detection on that weighted wire will out perform it for precision. Works every time for my bottom fishin'.

(Well, mostly. But that's another story.)



Good luck.

 

[MacTechVpr]

Guess what I'm tryin' to say gang is we most of us prolly can leverage a combined strain through micro tools and leverage as any simple jig can, perhaps more. More than enough, and by far. So btw and for example, if the wire's so tight you can barely pull the bit or drill blank you're way to tight. That wind will definitely go hot right to the posts. And yeah, this happens with a pin vise in most gauges. As well breaking wire right up to twisted 30AWG. Some thoughts on Newtons.

Good luck.

 

[Alexander Mundy]

275N = 28Kg at 1G

 

[MacTechVpr]

I'm not quite getting that picture well ah.. maybe I'm not sure the wire will stay in the jaws sideways? I'm game, seems maybe it would be easier to feel the pressure than pulling out from it. My pin vise isn't here yet but I have a reasonable facsimile I can try. So what you are saying is just plain downforce is not enough and actually might need to be even heavier to do any good

No didn't mean to give that impression. Weighted downforce can work. Just a bit more cumbersome to determine the sweet spot. Great when you nail it. And if it's more effective for you to build consistent strain that's good news for me. I may have to go there soon.

My game plan was to encourage folks to use something plentiful, a common instrument screwdriver. And hope they'd drop the 5$ on a pin vise when they saw what strain can do for their vape. What it turned into was the revelation that a pin vise can serve as the barometer for what strain can accomplish at a given wire gauge. That the best strain gauge we have is right inside our heads.

What I can tell ya is that motor memory is quite real and in play here. I've been thrown off by changes within a single gauge from the same producer. Found out one time when I started breaking every other wind to realize that particular run must have been slightly under spec for dia. So yeah, variations can happen over rather short lengths.

Good luck APS.

 

[Skepticide]

If you want consistency in tensioned coils, then you have to build a device that will exert specific tension on the wire and hold it there while the coil is wrapped. I believe you can achieve this more accurately and with smaller hardware, using a guitar tuning knob. And, much like a guitar string, you can gauge the amount of tension by plucking the string and measuring the pitch with an electric tuner.

 

[etherealink]

If you want consistency in tensioned coils, then you have to build a device that will exert specific tension on the wire and hold it there while the coil is wrapped. I believe you can achieve this more accurately and with smaller hardware, using a guitar tuning knob. And, much like a guitar string, you can gauge the amount of tension by plucking the string and measuring the pitch with an electric tuner.

Interesting idea, I'll have to check it out... might require an oscilloscope

 

[MacTechVpr]

If you want consistency in tensioned coils, then you have to build a device that will exert specific tension on the wire and hold it there while the coil is wrapped. I believe you can achieve this more accurately and with smaller hardware, using a guitar tuning knob. And, much like a guitar string, you can gauge the amount of tension by plucking the string and measuring the pitch with an electric tuner.

Excellent idea. I like it. But internal strain varies along the wire. Now how to pluck in real time without rotation discernibly affecting pitch. You see consistency of strain relies on continuous rotation. So that would require the wire to be in a constant state of vibration. What would be the sampling interval? The precision of the tuner? And I want to drive this widget with my 18650 battery. But I agree, if practicable, frequency could be an important measure. I think the scale you envision with machine heads is on point. Duplicating the accuracy of the brain's ability to differentiate oscillation at better than 1/100 sec is a challenge. And did I mention I wind AWG 24 two inches from the bit? Not bustin' ya. I actually like the idea skip.

A simple sandwich assembly using the spool, a rudimentary drag (could be rubber grommets) and a machine head type driver for the mandrel. Compact spacing, wire spread and efficient. Spin it slowly and ping as you go. Bingo.

Long term for me, I'm going to need one. New vapers need to just be able to throw the spool on it and wind. Re-spooling, too much fiddly. Wire angle, wire migration, a big problem for consistent strain.

Interesting when you wind with a pin vise. You get to sense all the physical forces. For ex, too much of an attack angle or bias (off perpendicular) towards the wind, repulsive forces and geometry constrain the wire to line up at precise adhesion (given enough tension) alongside the prior turn. Strain inhibits over-wrapping and the wire emits quite a noticeable ping! This signals that the attack angle is too far off the natural turn bias…you're inducing too much longitudinal strain against the wind. Despite all this complexity, to a new winder it's intuitively like a wow moment of revelation…ahhh, too tight.

Haven't quite hit on how to dup what we do with PV hand winding. Just not easy…but I'm workin' on it.

Thanks for the input!

Good luck S.

 

[Skepticide]

I'm envisioning a very simple device that is cheap to manufacture and easy to use. Two arms rotate around a center post and overlap, exactly like the hands on a clock except they turn counter to each other (they would be geared for precise rotation). One end of the wire is fixed at the end of one arm in the 9 o'clock position, and the other end is attached to the tuning knob at the end of the other arm in the 3 o'clock position. Tune the wire to the desired pitch, then insert a jig into the center post and rotate arms to wrap the coil.

The obvious hurdle here is the fact that the wire will get shorter as you turn, thus increasing the tension with each wrap. Theoretically, the increasing tension should distribute evenly because the wire can spin on the jig. If that proves not to be the case, then it would require tuning knobs on both arms with a sample/adjust both on every turn, but I don't think that will really be necessary to get the wrap we want.

The nerdy bonus to something like this is that with pitch as a quantifiable measurement of tension, tabular data can be recorded to make a chart with the right settings for any combination of wire gauge, jig size and wrap count.

Edit: just a thought, does the amount of tension on a wire affect the amount of resistance in the wire?

 

[MacTechVpr]

My focus is on new vapers. Like you said, keep it simple so they consider the advantages of rebuilding. And cause it's got to be affordable or practical to put together for most. Or, don't help us none. Difficult challenge but I'm with ya. Work with anyone on ideas, and I have, to get them there.

Yep, res does change with strain level applied. It's minimal but you are adding heat energy to the wire. Oxidation is critical with tension then. That heat increase even tho minute per mm can add up quick over the length of the wire if a contact coil if circuit bypass remains. The more gaps, the less consistent the insulation, the worse. Why I insist so much. Want to see all get the best out of the effort.

I do see the problems with adjustment and variability for mechanical jigs.

Biggest problem I see with a mech is alignment to wire, as I was sayin'. Wire feeds off different angles. Worse if you hand transfer wire to a spool. It gets messy. And you need some type of spooling for a mech jig. A solution could be an interim ceramic guide (or take-up roller, tensioner) to fix the wire feed angle to the bit at an optimal distance (close).

I'm eager to see what others may contribute.

Good luck S.

 

[Skepticide]

The design that is evolving in my head doesn't use a spool, you clip off a section of wire and attach each end to a different arm on the device. I'll see if I can't make some illustrations of the concept.

 

[Skepticide]

I threw together a 3D illustration for this design concept:

The idea is that you mount the wire first, tune it to the desired pitch (based on jig size, wire gauge and wrap count), then insert the jig and turn the crank. The arms will rotate opposite each other and wrap the coil from the inside out, evenly distributing the increasing tension as it turns.

 

[MacTechVpr]

I threw together a 3D illustration for this design concept:...The idea is that you mount the wire first, tune it to the desired pitch (based on jig size, wire gauge and wrap count), then insert the jig and turn the crank. The arms will rotate opposite each other and wrap the coil from the inside out, evenly distributing the increasing tension as it turns.

Nice rendering but I think we've strayed just a wee bit from the notion of machine head tuning and desktop strain winding.



Good luck S.

 

[laurie9300]

Now we just need to mount the fixed anchor and tuning head onto sliders with springs to maintain the tension...........

 

[Skepticide]

Nice rendering but I think we've strayed just a wee bit from the notion of machine head tuning and desktop strain winding.

Strayed how? That is what this device is for...

Now we just need to mount the fixed anchor and tuning head onto sliders with springs to maintain the tension...........

I'm not sure I understand your point here. Why would we need springs to maintain the tension?

 

[laurie9300]

I'm not sure I understand your point here. Why would we need springs to maintain the tension?

As the wire wraps around the shank, it will get shorter and shorter, pulling the two anchor points towards each other.

If these points were allowed to slide towards each other, under tension (hence the springs), you may get this to make a coil?

But IMO, this is way too complex.........

 

[oplholik]

I agree with laurie here, it's getting way too complex. I applaud the ingenuity here, and I do enjoy seeing , and reading, what comes out of it, but I think it is way too much just to get a little bit better coil and vape than what I'm getting now. The gizmo still gives me a great vape, and the coils last forever. I haven't used the coilmaster jig enough yet to compare, but seems to work well for me so far. This is as complex as I care to get at this time anyway. Just my opinion.

 

[Skepticide]

As the wire wraps around the shank, it will get shorter and shorter, pulling the two anchor points towards each other.

If these points were allowed to slide towards each other, under tension (hence the springs), you may get this to make a coil?

But IMO, this is way too complex.........

I get what you're saying now, the description was confusing but I think you're on the right track. Essentially, we need the mount points to give under a certain amount of tension so that we don't stretch and snap the wire. And that may actually be the key, because tension in those springs can be adjusted by compressing them, much like the knob on the bottom of an office chair that lets you adjust the resistance of the backrest spring.

In that regard, the machine would be much simpler to operate:

1. Set dial on tension springs to selected wire gauge
2. Mount wire on anchors, hand tighten as far as it will go without stretching the tension springs
3. Turn crank 1/2 turn for each wrap (each arm completes half a wrap)

And I agree with you both, the whole topic is convoluted. The premise of a TMC is entirely true; wrapping under tension does in fact produce a superior coil. However, it shouldn't require a workbench or calculus or mastery of The Force to achieve a perfect coil. And that is the inspiration for this design, I want it to be a mechanically simple apparatus that can be assembled from a few cheaply machined parts and let you rapidly produce perfect TMC coils with little effort and no measuring.

 

[oplholik]

What I enjoy about seeing ideas like this, is the evolution, and, the refining, of the idea. Great stuff. W/O folks like you, we'd still be in the dark ages.

 

[Aal_]

Even if we are getting too complex about it I think the advantages here is having a self winding machine with minimal human intervention