Winding DIY Inductors

[kizm0]

Can I wind an inductor using regular 17 GA Steel?

It's called

"Oklahoma Steel & Wire" 1/4 Mile 17GA

[BOBinGA]

You can, but why would you? Steel has 7 times the resistance of copper. A 1.5mH 17 ga. inductor with copper might have half an ohm resistance. Wound with steel wire, it would have 3 1/2 ohms resistance and change your crossover points significantly.

-Bob

[kizm0]

Just wondering.. didn't feel like going out and buying stuff.

[kizm0]

Will a 28AWG 2.7 mH Inductor do the same job as a 14 AWG mH Inductor?

I bet it'll do a better job, but I'm just wondering. I'm trying to wind my own coils.

Besides that, what's a good home-made way to wind your own inductors?

[benchtester]

Can I wind an inductor using regular 17 GA Steel?

It's called

"Oklahoma Steel & Wire" 1/4 Mile 17GA

Besides the steel having more resistance, it is very import to determine the insulation. It isn't clear to me that this has any insulation on it. If there isn't any insulation then the current will jump from coil to coil and it will be a dead short, very unsafe for you and your amp. Most inductors are made with "magnet wire" which is copper with a thin lacquer or plastic coating insulation. It may look like bare wire, but it isn't.

http://en.wikipedia.org/wiki/Magnet_wire

Thinner wire (higher gage) is cheaper, smaller, and easier to work with; but lower gage thicker wire has lower resistance for the same amount of inductance. Less resistance means less of the power is lost in the coil.

[JonMarsh]

You need to get a handle on what wire gauge means... pronto.

Every two steps up in wire gauge number is cutting the cross section of the wire in half, and doubling the resistance.

Google is your friend- you need to learn to use it.

And the answer is no, not remotely.

[ThomasW]

Besides that, what's a good home-made way to wind your own inductors?

With a coil winder. Below is a picture of one I use. There are more pics in the link.

http://home.comcast.net/~audio-worx/page95Coilwinder.html

After you wind a few hundred inductors the cost of buying/building the winder begins to break even.

I buy 15 gauge copper wire from a electric motor rebuilding company. It's sold by the pound. A typical bucket costs $250 or so depending on the current 'spot' price of copper.

Don't forget bobbins and steel laminations also add to the cost. It's cheapest to buy bobbins in 100 lot quantities. You'll need several sizes

Having a solder pot makes stripping the insulation and tinning the leads easier. Those start around $90

To test the values of your homemade inductors you'll need to buy an LCR meter. Those start around $50, a really good one is several hundred $$$

Plan on sending the wire from your first dozen or so inductors to the recycling center since it takes a while to get a feel for doing this. If the wire is removed from the bobbin it's extremely problematic to reuse it as it doesn't want to lay flat. It's important that the layers of wire lay flat and all have equal tension.

HTH
Thomas

[JonMarsh]

Translation:

We know how to wind inductors on your own, but it's not worth the hassle and effort to do it for one project. Don't be penny wise and pound foolish; pony up for what the design specifies and reqiures.

[DeathMonk]

Thomas means business with his own coil winder

[kizm0]

JonMarsh: yes..I can be lazy sometimes. I really try to ask for help only when I need it.

Thomas: Good job on that Winder. The point of me winding my own coils was to save money(heh). I made a drill-bit that I can wind with..so thx.

[ThomasW]

The charts used to calculate the number of turns for a given inductor value are based on having perfectly windings. Those only occur with automatic machines they never occur with handmade units. So the DIYer must have an LCR meter to measure their home made inductors. Unfortunately those meters cost more than buying premade coils.

[kizm0]

How to count number of Winding turns using a webcam *Idea*

A webcam is usually 30FPS.

As long as the winder doesn't spin faster than 30 times per second, then you can use this idea.

Simply place a sensor(maybe a L.e.d) onto a part of your winder(that turns) and program something that will make a count each time the LED disappears and appears completely. It's all about somebody on here programming this and sharing it. Maybe there are forums where somebody can help us do this.

Just give me credit for the overall idea .

[kizm0]

Here are some "Inductors" I made using my drill-bit that cost $0 and took about 5 minutes to build. Then 45 hours to get used to (completely, honestly(I just began winding)).

[ThomasW]

Threads merged. It would be wise not to start a separate thread for every thought you have on this topic.

[DeathMonk]

unless you need a huge one, inductors don't cost all that much.. And if you needed one that big, good luck winding one with that setup.

So why bother?

[---k---]

Here are some "Inductors" I made using my drill-bit that cost $0 and took about 5 minutes to build. Then 45 hours to get used to (completely, honestly(I just began winding)).

So how does it sound?

[kirknelson]

It you are really adamant about making your own inductors then this is a good way to measure them:

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=390-804&ctab=1#Tabs

Accurate to +/-1% for $100 and it will measure driver parameters too.

[kizm0]

---k---:

Those were tests..I'll come back with the completely made inductors when I get the metal.

Kirknelson:

I found a LCR Meter for $25 Shipped. I think I'll just buy that.

# 4 Inductance Measuring Ranges :
20mH / 200mH / 2H / 20H, +/- 2.5%, + 5 digits;

That's not bad at all. 1.5% more for 1/4 the price.

[kizm0]

Also:

Will this replace "5.0 ohm Eagle 10 Watt Metal Oxide "?

[ThomasW]

So how does it sound?

The question is irrelevant since there's no basis for comparison.

Also:

Will this replace "5.0 ohm Eagle 10 Watt Metal Oxide "?

No.

[---k---]

[QUOTE=ThomasW]

The question is irrelevant since there's no basis for comparison.

No.

I know. :twisted:


Help me, why not? Both are 5ohm and both are 10W. Is it because it isn't non-inductive? I thought I read somewhere that non-inductive resitors still have so small induction that it didn't matter. of course I read it on the internet.

The Eagle are dirt cheap, so I'm confused though why they are trying to swap.

[JonMarsh]

At some point these discussions seem to wind up in the noise floor...

price is in the noise floor as regards difference- a buck twenty versus 80 cents? This is much less of an issue than 28 AWG inductors! :W

[ThomasW]

Newark, Digi-Key and other suppliers have a $25 min purchase. Does it make sense to pay $25 for an $0.80 part?

[---k---]

So the part is okay to swap, it just doesn't make sense because of shipping costs...

Just wanted to make sure I wasn't missing something.

[ThomasW]

Shipping costs are not included in the $25 min purchase, shipping will add on another $5 or more

[kizm0]

Newark, Digi-Key and other suppliers have a $25 min purchase. Does it make sense to pay $25 for an $0.80 part?

You are misinformed. Newark does not have any min purchase. Individual manufacturers\parts may have a minimum quantity allowed for purchase, but I am at the last step of check-out with only $5 Shipped in parts.

So with this new information...would buying the Ceramic resistor vs the Metal Oxide resistor be any different?

Can I get away with purchasing the cheaper one?

[ThomasW]

You are misinformed.

Well excuse me. I don't order much from them. In years past they've had a min order. If that's now changed fine.

So with this new information...would buying the Ceramic resistor vs the Metal Oxide resistor be any different?

Color me old fashioned but I won't use any resistor in a crossover unless it's specifically labeled non-inductive, others may choose to ignore this detail

[kizm0]

Well I think it's a great thing that Newark doesn't have this minimum order.

Also, use the SAVE5 Coupon to save 5%

[cjd]

Give yourself 20 years and you may end up laughing at the amount of time you're spending to save a few bucks.

Understand that we have no way of guaranteeing even the level of guarantee we usually have on the results you'll achieve with the changes you're making. Some of the changes being asked about would have quite detrimental results (28ga inductor for example). Even your inductors could have quite different results at the same mH value (impedance may differ significantly).

Keep having fun.

And don't poke Thomas - he bites.

[Amphiprion]

Why spend money on Eagle resistors when you can get perfectly fine and much more available wirewound sand cast jobs?

Just an FYI, I think Digikey also dropped their minimum order requirement. But even then, you can usually get speaker appropriate passives cheaper at Madisound and PE.

[---k---]

The Eagle and the PE Sandcast are the same price, $1.20

You're thinking of the Mills which are $3.75

[kizm0]

Check out my thread on my ZMV5 build. I'm pretty much done here.

Thanks!