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Jerrod Miller

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Jerrod Miller last won the day on December 12 2018

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About Jerrod Miller

  • Birthday 03/25/1984

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    Jerrod Miller 25
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  • Location
    Spokane Washington
  • Interests
    Steel metallurgy, HEMA, forging (blades and otherwise).

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  1. Jerrod Miller

    need some advice

    You should be fine, but in general that tends to make things worse rather than better. Still air cool is all you need (for this alloy and other simple ones).
  2. Jerrod Miller

    What Why Where and How?

    Generally no, but I do stand right next to them with my wallet and cell phone. My bank cards always work and never had a problem with the phone. Nope, well below average. Average arc furnace is closer to 10 times that size. That is on par with the smallest I have seen running. 4 times that size is relatively common for foundries, but the steel mills are where the big ones are most common. 30 tons (or 6 times the one in that video) is about as small as you're likely to find there. 40 and 50 ton are pretty dang common, as far as one can say for steel production; it isn't like there is a steel mill in every town.
  3. Jerrod Miller

    What Why Where and How?

    Some might also find this interesting: The smallest arc furnace I have seen running in a production shop is 5 tons. I have seen a 3 ton in a shop, but not being used. Anything smaller than 5 tons is generally induction melted. Obviously this isn't a rule set in stone, just something I have observed to be generally accurate.
  4. Jerrod Miller

    The incredible disappearing steel

    Somewhere on the forum there was a discussion on material loss in projects like this. I seem to recall that the consensus was at least 30% if everything is ideal. Any step away from that just makes things worse. If you can, a picture of your set-up would help. Modifications for a huge improvement may be quick and easy.
  5. Jerrod Miller

    My first knife. Something I made over Christmas

    I like to think of it in the exact opposite perspective (though yours isn't wrong). Given enough energy (heat), oxygen can then rip the carbon away from the iron. The key here is the oxygen. If there is no oxygen, there is no decarb. Likewise, if the oxygen simply can't get to the carbon (steel), it can't react, which is the premise of using anti-scale. And if there is a lot of oxygen, there is a lot of potential reaction.
  6. Jerrod Miller

    Now we're cookin' with... er... magnetism?

    They only draw as much power is goes into the metal, so they are by far the most efficient user of energy. That being said, you can calculate your power usage yourself based on your local power rates. For the sake of argument here, let's assume you forge for an hour, and half that time is heating the metal (so 30 minutes of power on time). Let's also assume it is always pulling max power (it won't), and that your power rate is $0.10/kWh. Therefore: 15kW*0.5Hr*$0.10/kWh = $0.75 per hour of forging. Of course your power company mage charge something else, and maybe your heating vs hammering vs planning times are different. But now you have the equation, so you can plug in your own numbers.
  7. Jerrod Miller

    What Why Where and How?

    Also, in those facilities I mentioned, that was the only method of melting in those facilities. I have also worked in and been to shops using electric arc furnaces, and that is where you start getting really big melts. The foundry I worked for in Tacoma could melt and pour 96,500 pounds at a time. Cupola melting is also still done, but not nearly as much as it was 100 years ago. Electricity offers a lot of advantages.
  8. Jerrod Miller

    What Why Where and How?

    For several decades now. Probably since the 50s or 60s. The first foundry I worked at had 500, 1500, 2500, and 6000 pound pots. I think those power supplies were from the 70s or early 80s. The foundry I work at now only has 1500, 2000, and 3000 pound pots. Those are maximum capacities, you can run a furnace about 2/3 full without issue. I have been in facilities with 20,000 pound induction pots, too.
  9. Jerrod Miller

    The incredible disappearing steel

    Also to be clear, 0% of your volume loss is compaction. When we are talking about volume of starting steel and ending steel. You may compacting a billet in terms of removing air gaps, but the density of the steel remains constant.
  10. Jerrod Miller

    What Why Where and How?

    That specific video is aluminum. Once the magnetic field passes through the work piece (the aluminum in this example), that magnetic field then induces a matching current; like the one in the copper coil that started things. There is then electric eddy currents that cause heating through resistance. That is why any conductive metal works. You just have to tune the frequency the based on the size and resistance of the metal being heated. And this changes with temperature, so good systems have automated frequency tuning.
  11. Jerrod Miller

    What Why Where and How?

    Your metal doesn't actually have to be in the coil. Google up a "pancake induction coil" (or just click this link). This can work for larger stuff.
  12. Jerrod Miller

    Garage Door Torsion Spring

    Gravers, punches, etc.
  13. Jerrod Miller

    What Why Where and How?

    I'd consider $3000 an amazing find for a 12-15kW unit, made in China (or similar). A good US made unit will probably be at least double that. You can, however, get <1kW units that are used for heating automotive parts (or similar) just enough to weaken glue for just over $1000. Last I checked, about 2 years ago or so.
  14. Jerrod Miller

    What Why Where and How?

    It is a bit low power (10kW is the largest unit they offer there), but maybe not too bad. @Justin Mercier has a 15kW unit.
  15. Jerrod Miller

    What Why Where and How?

    There are a couple people on the forum that have induction forges, including Dave Stephens.