Winding Air Core Inductor

[timp]

Can anyone teach me how to wind air cores? I thought experimenting with xovers will be more feasible if i can build my own air cores. What is the best way to do it or is it too time consuming and not practical. Please help.

Thank you.

Tim

[bowtie427ss]

I applaud your enthusiasm, but unless you have access to a lathe with back gear and an accurate way to measure inductance, i'd leave winding inductors to the companies that do it commercially.

Sure there are recipes out there that will tell you that X feet of X guage wire wound on X diameter former with a winding height of X will net you approximately X millihenries. Too many X's for me.

But, you have to be able to stack the windings very precisely and uniformly, or your inductors will vary too much in value.

Factory wound inductors are an economical soulution when you consider that their values observe a pretty close tolerance, and even then i've occasionally removed a couple turns here and there to better match pairs or get an exact value that wasn't offered.

Just my .02 y'all understand...........

[timp]

Thanks bowtie

I got you. Stupid is what stupid does. I sure does stupid sometimes.

By the way. Is it ok to add different values to make a desired values? The shop is out of 4mh. So, can i add 2mh+2mh=4mh? Or is that a no no. My gut feeling says yes. But I've been wrong many times here. So.

Thanks again for the reply. Always thankful. I am going to a shop tomorrow to pick up some inductors.

Tim

[Old Guy]

Wish I had a copy of Badmaieff?davis book "How to build speaker enclosures".

It gives dimensions of a coil form and instructions on DIY. I'd gladly post the pages.

I sold my copy when someone offered 450 for it, it was a clean first edition. i can get a dog eared second edition for $20 or less...

But only useful as a learning experience- you won't save any money.

[Old Guy]

Something to play with-

http://www.colomar.com/Shavano/inductor_info.html

Agian, it will probably cost more, but one man's cost is another man's fun.

[timp]

Thanks for the reply. To be honest. I am so tempted to try. But, In the words of dirty harry "man's gotto know his limit." But something inside of me saying, "wll punk, do you feel lucky?...go ahead. make my day!"

Tim

[Audio_by_Goodwill]

Originally posted by Old Guy:
Wish I had a copy of Badmaieff?davis book .........
I sold my copy when someone offered 450 for it, it was a clean first edition. i can get a dog eared second edition for $20 or less...

<font size="2" face="Verdana, Helvetica, sans-serif">Wow, was it a 1st printing? I think most if not all are 1 editions. Mine says 1st edition, 11 printing. I know that book goes pretty high on Ebay, but I've never heard of one going for as high as yours did.... that's incredible!

I've tinkered with the idea of winding my own inductor, but I've always decided that I didn't really need yet another project. I've read a few web pages on doing it, Though. The guys that do it, will scavenge wire from random cast off transformers, quite often. They seem to have fun with it.

[Old Guy]

I apolise- hit the shift key it becomes $50

[donaldpatten]

Timp

Go for it .
I use an old hand crank drill, mounted in my vise. The drill turns a threaded 1/4-20 brass rod. The rod end in the drill chuck ,
is filed to a triangular shape so it will not slip. A brass nut and plastic washer hold one side of the coil form on the rod, the other side has a second plastic washer and plastic knob with a brass insert . By using brass I can
measure a coil on the drill.
The coil form is wooden dowel rod with plastic flanges on the ends. I use broom handles drilled with a 1/4?hole down the center . Two slots are cut into the side to hold cabe ties parallel to the hole down the center. Two Peanut Butter jar lids are drilled and slotted to form the flanges. A center 1/4? hole fits the threaded brass rod. Two radial slots are cut to allow the cable ties to be in the dowel slots under the starting layer of wire. When finished, adding turns of wire, pass the cable ties back through the slots over the finished layer of wire, and tighten. Now remove the coil and form from the drill . Remove the flanges, and push out the dowel .
If you want to measure a coil on the drill without cutting the wire from the supply spool, use an Exacto knife connected to LRC meter and nick the wire coating to make a connection . The inside end can be stripped to connect the start end. Leave long wire tails to allow tweeking. To tune a coil add or remove turns.
Don

[timp]

That is something I have never thought of. I will be looking around.

Thank you.

Tim