Jeanna:

One thing Jim and I were discussing a while ago was how to determine "soft iron".  We figured that it would not be too hard to test various materials by winding a few turns of insulated copper wire around them and doing the same sort of test that you have done. The big difference here is that you will not have already wound all that wire on your NS coil yet.  5 or six turns of wire and run by a 9 volt will tell you if it holds magnetism or not.  Might even work with an AA I am not sure.

I wish we could find some decently priced ferrite rods of suitable size as I am convinced that they would work well for us just like on our toroids with our JTs.

Bill

Quote from: Pirate88179 on April 07, 2010, 03:58:54 PM
http://www.youtube.com/watch?v=3tDX85ZK14Q&playnext_from=TL&videos=_7BN2CF9X1c&feature=rec-rn-2r-6-HM

Check out this MIT early wireless telegraph demonstration.  A solenoid within a solenoid and 2 spark gaps powered by 12 volts.  The 2nd spark gap has a spark of about 9" long!  This could easily be related to the NS coil and make/break idea as it was just about in the same time period.

Bill

Some time ago I was attracted to Stubblefield photos with rods sticking out of the ground from a thread on this site.
It looked like there are ringer bells at the top, then a coil, then another bell. The kind of bell you'd see on an old wooden
wall phone or candle stick ringer box. However, those old phones had the cranks. Haven't found any cranks on any
Stubblefield phones.

Take care.

nap

Bill
I remember now, that Hans told us that an antenna would work.
I bought a thrift store radio with an antenna shortly after that.
But, I never made a NS coil with it. I made one with a straw, and I think the antenna will fit.
Maybe I can find all these things.
It has been 2 years since we did that.

But, my kit came with a nail which was soft iron.
We both used nails in our bedini cores.
I wonder if the hardware store would mind...
Welding rods are pretty thin, but so is that nail/
I am thinking out loud here. I guess I can use one of these welding rods.
I could buy some without the borax too.
That would be easier than chipping it off.
I'll go put one out in the rain. Maybe that will work.

I did get some of that cotton covered wire.
I am sooo glad the wire in this reed switch motor is the same gauge as the cotton covered wire I bought.

Maybe it is time to read the patent again.

jeanna

Hey I found some old iron bolts on ebay if anyone is interested:
http://cgi.ebay.com/Lot-22-Vintage-Black-Iron-Carriage-Bolts_W0QQitemZ130303984925QQcmdZViewItemQQptZBI_Tool_Work_Holding?hash=item1e56b9051d

They look like they would be good to use as coil cores...

Doug

From my research on Soft iron.
"The "soft iron" variety is almost pure iron, with up to 10% silicon. The 1018 has been the most common throughout the world."
The bolt that NS used was problably the same or close to it.
I found that the 1018 has the lowest amounts of other materiels.

http://www.onlinemetals.com/alloycat.cfm?alloy=1018

I went to my local machine shop but he didnt know the specs on soft iron. He gave me a 3/4 inch foot long piece and a short 4 inch piece to try out. I put the short piece on 2 Microwave toroidal magnets over night. Took it it off and it wouldnt even pick up a tiny steel washer. I dont know if this was 1018 or not. I then put galvanized iron wire on the magnets and it did pick up the washer a little before it demagnetized in a few  seconds.
Heres something I did playing around with the 3/4" 4 inch piece of steel. I took the 2 toroidal magnets and put the 4 inch rod through them. I then took 2 C battery's and put one on each end of the bar. Put my meter on it and got 3 volts. One battery alone with the magnets shows the 1.5 volts. Without the magnets I didnt get any voltage. I thought that was interesting.

Pulsed Dc FYI
As soon as you add inductance to a pulsed DC circuit you almost always end up with some current of the opposite polarity due to the flyback effect of the collapsing field.
One should also note that the flyback effect does occur if you DC pulse a transformer, you will end up with some AC current.