[Elecraft] On hand-twisting wires for bifilar windings...

Thu Oct 2 15:53:01 2003

I used a pair of Vice-Grips and a pair of safety-wire pliers.  I put the wires side-by-side and clamped the Vice-Grips on them.  The I put the Vice-Grips *lightly* in a bench vice.  Then, I clamped the safety-wire pliers on the other end of the wires.  I twisted the safety-wire pliers with the knob that spins them and kept measuring the twists with a ruler until I had the correct number of turns per inch.  It worked great!

Dan Allen
KB4ZVM
K-2 S/N 1757

> From: Tom Hammond <[email protected]>
> Date: 2003/10/02 Thu AM 02:27:10 EDT
> To: [email protected]
> Subject: [Elecraft] On hand-twisting wires for bifilar windings...
> 
> Hi Folks:
> 
> Upon Dave, KK7SS', suggestion, I'm posting this message to the reflector 
> for the possible benefit of newbie builders who are agonizing about how to 
> get the proper amount of 'twist' into the wires they're winding for a 
> bifilar-wound transformer, such as those used in all the Elecraft ATU's and 
> the KPA100.
> 
> Dave wrote:
> 
> >Another question..
> >
> >For the KXAT1, T1 uses a pair of wires, twisted together at 4 tpi. Having 
> >done this before, and having messed it up at least three times, do you 
> >have a method than can be done by hand that works well??
> >
> >I'd use a drill, but my eldest boy borrowed it and (naturally) can't find 
> >it. If not, I'm going to try by using the same method I use to braid my 
> >daughters hair
> 
> Heheh...
> 
> Well, I'd already taught myself to do it long before someone else brought 
> up the subject of using a drill motor... MUCH too easy for me anyway... If 
> there's a difficult way to do it, I'll probably find it.
> 
> The way I do it is to place both wires together, side by side and make a 
> couple TIGHT twists at one end, and for no more than 1/2"-3/4" of the 
> length. These are JUST to hold the wire ends together and they're CUT from 
> the final product once it's been more properly wound.
> 
> I ensure that each wire in as straight as I can easily make it, and I then 
> hold the twisted end between my thumb and next two fingers with one wire 
> extending back between the thumb and forefinger and the other wire 
> extending back between the forefinger and the middle finger.
> 
> Next, I grasp the twisted end with the other hand and continue twisting on 
> it AS I pull it away from my fingers. This allows me to impart a measured 
> twist to the wires out ahead of my fingers while allowing the free ends of 
> the wires to UNtwist, in response to the twisting I'm doing up front.
> 
> If you secure the untwisted wire ends, the twist you impart at the front 
> will try to cause the loose wires to 'take a set' and this is something you 
> don't want to happen. It's just like when the Boy Scouts used to make their 
> own rope... if you've ever seen their rope-making machines, one end 
> imparted the twist and then the twist was released at the back end.
> 
> This method works great for me... been using it for a couple decades, I 
> guess. It's a helluva lot longer to explain that it is to DO!
> 
> Hope this helps.
> 
> 73,
> 
> Tom  N0SS
> 
> p.s.
> 
> Yes, you CAN use a drill motor to do the winding, but, generally, by the 
> time you get the drill out and set up, I can have the wires all twisted by 
> hand and I'm on to more building.
> 
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