I'm going to agree with the coil wrapping discussion going on here, but also going to add that having the whole wire in tension is not what's really the critical issue. what is the critical issue is having the part of the wire currently being formed to be under tension. a full wrap is 360 degrees of rotation, a coil being wrapped is really only under deforming tension for maybe 15-20 degrees at a time, at the leading edge of where it transforms/bends/reshapes as a ring from a straight length, spiraling around and around, forming wrap after wrap.
unless you are applying enough tension to actually stretch the wire, which is not happening at all with any hand wrapping, then the important thing is that the wire has tension right at the point it is being reshaped from a straight length into a ring. I agree that doing this uniformly and consistently with conventional hand wrapping on a stationary jig is not possible and this became immediately apparent to me from my first time wrapping around a tiny screwdriver. wrapping with the over-back-down-forward-up type motion of wrapping to a stationary jig is virtually impossible to do with consistent tension and pressure at this critical point of transition, which is the point where the wire goes from a straight length to being formed to a tight ring.
the tension method shown here is very good and achieves the goal of consistent pressure and opposing force at this critical point of transition, the point where the wire is being re formed from relatively straight to a tight diameter ring. kudo's for that, it is a very good and consent method of achieving the goal, BUT, I have to say that although this is one way, and a very valid way of achieving that goal, it is really not the only way, and I believe that pinching the wire tight enough at this same point of transition will achieve the same or at least very similar and equally consistent results.
if you study the engineering behind cold mandrel bending and extrude forming, cold metal forming in general and what happens when metal is re shaped you'll understand how whats happening is really only happening at this one specific point of wire at a time, at this ~15-20 deg radius of re forming at any given point of wrapping. pinching the wire tight enough at this point of transition will achieve about the same thing as pulling tight as you wrap against the tension. both are causing the high pressure deformation at that single point of transformation. your pinch at the deforming point acts as a mandrel. pinching tightly while spinning the forming jig can accomplish very much the same thing as pulling and then spinning against the tension and result in just as even and consistently uniform
I've been saying this for a while now and I do get perfect tight
coils with just the pinching method, so perfect that no annealing is ever necessary and more than 90% of the time I wrap a coil with just pinching as it's wrapped it goes on the mod and fires perfectly, from the center outwards, with no need to even squeeze the coil after the first heat up at all, and this is all with just a smal length of wire not even on a spool.
so bottom line to me is, wrapping like this is a significant improvement over wrapping on a stationary jig with hand over-back-down-under-up etc... but it's not the only way to accomplish this. I still think spinning while pinching is the easiest and quickest to me but you need 2 things, a very strong pinch with tough fingertips and a crank handle on your spinning form to be able to keep enough tension and pulling as the wire is reformed from relatively straight to a series of tight rings in a spiral. of course pulling tightly to a drill bit in a drill and then spinning it up with the drill will too achieve these results.
this is how my coils come off with just pinch and twist. my whole point is not to knock this method as it is great, just not the only way, and not necessarily superior to other methods which can achieve the same results
