DIY Electrical Annealing Of Rifle Cases

See, The EE just went over my head, I'm busy looking up reference materials and electrical encyclopedia again!

The EE that stumbled onto this tread on a 'Google' search contacted me with some suggestions,
I spent WEEKS digging around trying to understand what he sent me...

I got a much better understanding of what I was observing through experimentation, and really good ideas on how to fine tune what we are attempting.

One example, long conductor runs to the work coil...
When those 'Reach' runs were far apart, the unit heated the brass much slower.
I rotated the coil from vertical to horizontal which put the runs very close together.
Suddenly I was over cooking brass in a heartbeat!

Run conductors to the work coil SEPARATED sap energy from the actual work coil,
While keeping those run conductors close together canceled out the losses and delivered MUCH more energy to the work coil.

When I figured this out, I had forgotten the OBJECTIVE was to deliver MAGNETIC energy to the work coil/brass.
When far apart, the magnetic field is wasted on the way to the coil, just 'Dumped' in open space.
When conductor runs are close together, the excite electrical current IN EACH OTHER, maintaining the overall current supply to the work coil.

Every magnetic field passing through an electrical conductor produces electrical 'Potential', and in this case, the electrical circuit is completed, so that magnetic field induces CURRENT (connected & moving somewhere) in the conductor run right next to it, back and forth between conductors.

Not 'Perfect', but certainly reduces losses in long conductor runs to the work coil!
 
It has been so long ago I do not remember all the details but it had to do with a SCR506 radio with what the Army called a Dyno for the transmitter side. When the radio was keyed up the Dyno hummed with the sound of high RPMs. In the instructions there was a warning about touching the antenna seems there was something about RF that was not healthy. Many of the old radios became surplus/salvage meaning not many of them survived.

Anyhow, there was an old friend of Einstein and professor at Princeton dealt in Early American Junque on the west side of New Jersey near Lebanon. When in the area I would visit, there were several items that came available to him that he did not think people should have access to so he saved those items for me. On one of my visits I noticed he had two Dynos for the SCR506 transmitter, he made me a deal. He said he would be desperate to find anyone that knew what they were and no one had the wiring harness to complete a circuit. Anyhow, I explained to him with little effort the units could be converted to an arch welder. What that means when converted there are two wires coming from the Dyno, one is + and the other is -.

The conversion was made possible by a sailor that went into the Navy to work in the galley of a ship because he was African/American. When it came to electricity he was a Genius.

F. Guffey
 
That is the only inexpensive 12 Volt high current supply I can come up with off hand.
Click to expand...

Reloadron, what do you consider to be 12 volt with high current? With no effort I can burn wires up with 12 volts.

F. Guffey
 
You've either neutralized the magnetic fields like in a non-inductive wirewound resistor, or created a low impedance transmission line that matched the load better. What diameters were the leads and how far apart were they before and after? How many turns in the coil and what ID and OD?
 
Getting ahead of me again.
I was 1/4" copper tube with about 18" of lead on each side of the coil.
worked the same with 10 & 12 ga. solid core copper wire.

I had an 18" lead between induction unit and coil where it was mounted to drop cases into it.
Getting the leads within the width of themselves (small gap) increased the function of the coil.
I started with about 2" & 3" gap between leads on different units, reduced to the thickness of the conductor or less, usually two layers of fiberglass high heat sleeve.

From what I could glean from available information, the leads were shedding their magnetic field through induction to the other lead.
The EE said this is very common practice with induction units, and although I had stumbled onto it, it was basically correct, but not technically explained very well.

I have since reduced lead run length, eliminating the issue almost all together, I just thought it was interesting and relevant if we proceed. Something to keep in mind at the very least...

Doesn't matter if it's your actual tubing/wire the coil is made of, or if it's added wire length (Strand Wire) from unit to coil, the same rule applies as near as I can tell.
That's based on trying the tubing coil further away from the work coil (Tubing) and conducting the current from unit to coil with stranded wiring.

I'm aware of resistance in wiring, checking that, but couldn't find any significant changes in resistance, the runs were too short to produce much of a change in resistance. I also make sure I use good virgin copper tubing & wire, no high resistance alloys...
 
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Reloadron, what do you consider to be 12 volt with high current? With no effort I can burn wires up with 12 volts.

F. Guffey
Click to expand...

What do I consider "high current"? I really don't know, maybe exceeding 20 amps. Really depends on the application. As to burning wires up? Depends on the wire gauge. Now is 20 Amps really high current? Nope, not really but it's all about a point of reference I guess. Heck, when cranking the engine to start I would guess my truck starter draws a few hundred amps at about 12 volts.

One quick note about dynamotors which have been mentioned before. When I was a kid growing up in the 50s I grew up in Brooklyn, NY. Canal St. in Lower Manhattan was the war surplus district with mountains of stuff from WW II and Korea. No shortage of dynamotors. My first ham rigs were ARC-5 Command radios.

I don't want to get off on tangents, while interesting motor generators the thread has no room for them.

When the wife and I return in February I will continue to experiment with induction heating and using induction heating to anneal brass. The brute power supply laying down at my sister's is a needed item.

I still haven't a clue how much power will be needed to anneal case necks in a nice time frame. I also want to look into turning the MOSFET gates On/Off using a timer. I would guess rather than power up and power down the entire unit that turning the gates on and off would be the way to go.

Ron
 
Yes. Using an adjustable timer to drive a P-channel MOSFET power switch makes sense to me. Put the MOSFET in series with a Schottky diode with a high enough voltage rating to protect it from flyback, and you'll have a power switch fast enough to ensure the tank rings on startup the way it should. The timer then will be the heat control.
 
That is my plan. :)

I did go down the basement rummaging and did find my old LCR bridge which actually works. The pictured coil with the roughly 2" ID is about 2.0 / 2.1 mH. I should be able to hit Lowes or Home Depot and get some 1/4" OD copper tube stock and wind another coil with a smaller ID.

I have several configurable octal base or 11 pin base timers. If the gate thinking works then I'll just make a simple one shot. Thanks for the reminder as to flyback diodes. Been awhile and this is well outside my former environment and comfort zone. :)

Thanks Nick
Ron
 
Like you, I've got a dated B-K LCR meter sitting in the basement. You remind me it's been so long since I had it and a number of other meters and various pieces of equipment out, that I should double-check that I've pulled all their batteries. I should also take all the vacuum tube equipment and other line powered gear out and give it AC in gradual steps with a Variac to let the electrolytic capacitors re-form their oxide layers.

I'll bet the old single-layer cylindrical air core coil formula put into Excel will come close enough to give you a good design basis for your substitute coils. I'm sure you have it, but for others reading, it is:

μH = (nr)² / (9r + 10l)

Where
μH is inductance in microhenries
n is the number of turns
r is the mean radius of the coil (¼(ID + OD)) in inches
l is the length of the coil in inches

It is generally credited with about 1% accuracy, which is better than the capacitor tolerances are likely to be.
 
Unclenick, thanks for the old formula. Should work in Excel I would think. Yeah, same deal, old test equipment with tubes. The batteries in a Simpson 269 were ugly and the 22.5 volt batteries are hard to find. I really don't even know why I have a Simpson 269? Had a few old Fluke DMMs and a 9V battery ate the whole connector. Someday I need a dumpster. :)

Ron
 
Ok. I pulled the trigger on the dual psu and the 1000 w unit. I picked up a few ferrite o's and some 12ga solid copper. I also bought a small timer which I plan to power a relay with. I'm obviously leaps and bounds behind you guys but I will post my results when my stuff comes in anyways. Thank you all for the help.

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Kris, we are about the same level, experiment to find instead of work it out mathematically.
I've tried green, yellow, brown & red large diameter ferrite, between 1.5 & 2"
And I'm having the best luck with 'green' right now.
I'm going to try a variable resistor in the spot where a fixed resistor is now and see what that gets me.

At $16 per pair with infinante adjustment knobs included it's worth a try.
This is from a guy that works with cartridge brass annealing for a living, so I'm confident he's not sending me on a goose chase...

A source for 1/8" dead copper (about 8 or 10 ga wire diameter) without buying an entire roll is hanging on the shelf at auto parts stores,
Nice length for this stuff. It's pure dead copper tubing for higher pressur automotive gauges.

Here is something for the 'Ironic' files,
That copper tubing is a little hard, I used an annealer to soften the tubing for an annealer!
This is a little small diameter for the old 'Pack Sand' to keep the tubing from linking, so I filled it with water and froze it.

Tried the 'Hot Glue' thing thinking the first time the tube heated I would just use air and blow the glue out...
Copper takes the heat out of hot glue WAY to fast to ever get the tube full...
Thought about throwing it back in the annealer to keep it warm while filling, but switched to water since freezing it was about 20 minutes outside right now!
 
Kris, just keep at it with your approach and don't hesitate to post any pictures, progress or even steps backwards. While I am pretty much stuck till I get the PSU I want up here I want to try and wind a smaller coil and maybe find a core and wind a C core. Thinking back if we look at The Annie Cartridge Induction Heater using the C form inductor it looks to have only a few turns on each leg. Also looking at the image it is difficult to tell if they are using a center tapped coil design? I can't make it out anyway.
Little by little we can all add to this thread with any progress or lessons learned.

Ron
 
From what I can tell it looks like the annie c core coil is outside tapped with the crossover in the center. You can see it better from some of the YouTube videos.

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Yeah, the videos are more revealing and there are some quite good videos out there. On another note, as to power supplies, a solution I have seen used is if you can find an old microwave transformer and using dremel tool or hacksaw cut the secondary off the core. Using some #12 AWG start winding a new secondary. Rumor control was like 30 or 40 hand wound turns should yield about 12 to 24 volts give or take. Works out to be pretty inexpensive and now I wish I had gutted the transformer from the old microwave. :)

Ron
 
I'm a pack rat with a recycle bin,
No microwave, TV, Computer monitor goes unmolested...
My first try at a case feeder was a microwave turntable motor.

And just for the record,
When I went from open coil to ferrite, 3 wraps on each side of the ferrite works just about right.
 
You can disassemble and rewind about any old transformer. I've done that by calculation for special purposes, like winding double box shielded power transformers for super low leakage instrumentation power supply applications. In that case, though, because the shielding was going to eat up space, the core had to be oversize for the power it was handling, and that's why the calculations needed to go from scratch.

But you can avoid that if you find a standard E-core transformer that still works and that has the power rating you want. The secondary is usually the outer turns on the bobbin unless it has a split bobbin (in which case you cut away only the windings on the secondary half of the bobbin. You can then put your own secondary on it as Ron described.

I have an old 1500 V-A 1:1 isolation transformer that would be a good candidate for this kind of alteration. I would want the new secondary to put out about 1/10 the voltage at 10 times the current, so the new secondary magnet wire I selected would have 10 times the cross-sectional area of the original secondary winding wire and 1/10 the number of turns. It's pretty much that simple.
 
So I have one psu up and running so I'm running the 1000watt unit on 12v. The coil that came with it was obviously very slow to heat steel or brass. I tried a black ferrite core with 3 wraps on each side. That did nothing to steel and slowly heated brass. Then I tried 4 wraps on each side with similar results. Then I tried a 1" coil with 7 wraps. That one seems to heat up the coil and heat sinks quicker than the target material. For the all the coils I made I used 12g solid copper. Any idea why everything over heated with the solid copper air coil?

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One heat sink definitely gets much hotter than the other. Even with the coil they provided. I can't see how this could be ran continuously.

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Kris,
Did you cut a slot in the ferrite?
A solid 'O' ferrite won't work, you need ends (poles) to focus magnetic energy

Ferrite has different values, I find 'Green' (painted or paint stripe) works best, but I have no idea how to test these things for their magnetic value, so I'm at the mercy of experimentation.
Maybe one of the EE's can explain the values and what we should be looking for...

Adding capacators have helped other people, increasing the 'Energy Tank' size.
 
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