AVR Freaks

kkogm,

Here's the deal with twisted-pair unjacketed wire. I speak from experience as I have had to procure specific types a number of times.

1. You will only find certain colors and gauges available in the open-market. Some of the previous posters gave you examples of their finds.

2. There are a few reasons why you do not find more choices.

First, there are just too many combinations of colors, wire gauges and insulation types to develop a "standard line" of pre-spooled twisted pair wire.

Second, most people will just buy one of the standard jacketed types available from Belden, Alpha, etc. if they can't find the unjacketed type.

Third, most assembly houses will twist small quantities themselves using a hand or electric drill.

Fourth, local wire suppliers can twist up any pair you need at minimal cost.

3. Local wire suppliers usually have a twisting machine in which they can load up 2 or more reels of whatever color and gauge wires you need twisted, twist it to your desired pitch (twists/inch), and spool it onto a "delivery reel" in a matter of minutes and at nominal cost. I have done this a few times for different projects where exact colors or gauges were either specified or required by design. In all cases the total lengths were a few hundred feet, and the suppliers did not balk at the small quantities. I guess because they do it routinely and the set-up is simple. If I recall, they either charged a penny or two per foot, or a per-reel price for the service.

The first time I procurred twisted pair from a wire supplier as I described above, I inquired why I had such a hard time finding "stock" spools. The salesmen explained to me what I described to you above. He also noted that he had dozens of spools of various gauges and colors of twisted pair in stock which were remanants, misorders, returns and the like. He offered me these at discount. Too bad, none of the colors and gauges he had on hand matched what I needed! Thus, making his point quite clearly.

In fact, he told me what he would really like to have is an UNTWISTING machine because he could buy surplus reels of unmarketable twisted-pair wire (like the ones he himself had in stock) for peanuts, untwist them and sell the spools readily as common single conductor hook-up wire.