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> 2007
> Cotton-wrapped #40 wire tesla ham rf inductor coil litz
Cotton-wrapped #40 wire tesla ham rf inductor coil litz
Old-fashioned cotton-wrap over enamel-insulated single-strand copper wire.
DCHF (D Cotton Hy. Formvar) made by the BRIDGEPORT INSULATED WIRE CO. of Connecticut in more modern times.
The combination of special enamel and cotton wrap make the wire tougher and better suited to wrapping and winding than plain wire. Each roll has its own, individually hand-numbered label and cardboard box.
I originally intended to use this stuff for winding some Tesla coils but don't have the time. Hopefully someone else can put this stuff to good use like rewinding damaged RF coils in antique or HAM radios or similar.
This spool weighs a total of about 260 grams (9.2oz), is 3.25" tall and 3" diameter.
I'd estimate 2700 feet (823 meters) of wire is on this spool, using the numbers below.
The OD of the insulated wire is about 0.014" The wire itself is about 0.003" diameter so you could wrap nearly 70 windings per inch.
The wire is wound on a section of the spool starting with an ID of about 1.875" and finishing with over 2.5" OD, over the 3.25" length of the spool if you want to try estimate the amount of wire on here as follows:
Perhaps around 140 ft on the top layer alone, 100 ft on the innermost layer, about 22 layers at an average of 120 ft per layer yields around 2680 ft of wire, which closely matches the NET number of 27 on the spool if NET is in 100s of feet. Other spools are listed as NET 27, 28 and 29 and one at 25. Other sizes of wire also available in #36 and #38 AWG. Please ask if interested.
See their website for some related technical info on Formvar and D cotton and thin copper wire in general:
http:// /specifications.php
http:// /ref_copperwire.php
click any image for a larger one
NOTE: these images are of just one of the spools.
Since all are very similar except for the amount of wire on them, or the appearance of the box the spool is in, these same photos will be used instead of shooting new ones for each individual spool.
difficult to shoot a good close-up of this very fine wire, here's a few to choose from below
* This item is unused and appears to be in excellent condition.
* Cardboard boxes containing each spool vary from good to some with minor water or physical damage but the spool and wire appear to be undamaged.
* Estimated age is between 5 and 20 years
* If you have any questions or concerns not covered by the information in this listing feel free to contact me and I'll try to answer quickly.
* No bank drafts, cheques, or COD.
Please feel free to contact me with any questions you may have and I will respond as quickly as possibly.
E-mail on weekends may not be answered until Monday or Tuesday.
