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Dan Hertzson

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  1. Just be certain they are rated for propane use. The cheap ones designed for compressed air are not suitable.
  2. I would alternately recommend 1080, 1084 or 1095 and 15N20 for pattern welding, and those simple steels for the kitchen knives. I have no idea what is available in Mexico, unfortunately, but these steels are all relatively easy to forge and heat treat.
  3. Longer burner mixing tubes will affect how much air is induced by the high speed gas flowing into the mixing tube entry. What size orifice did you drill and what pressure are you running at? Can you open the shutter you are using for the air more while it is running? Also, try opening the door a bit more. NA forges are picky about backpressure in the chamber. Most important: how far into the forge shell do the burners project? The end of the flare should be no more than 1/2" past the outer skin of the forge. Ideally there should be a thin "shelf" of forge insulatio
  4. I got out to the shop to have a try at my new 6150 stock this weekend as well. Didn't notice any significant difference forging it from other high carbon steels, though I was getting some pretty aggressive scaling, so I may have been forging at a relatively high temperature. Here is the rough forging (1.5" x 0.25" stock): Also did a snap test on a small sample of the same piece of stock, approximately 1/2" long with a shallow cut at the 1/3 mark. Thermocycled roughly and quenched twice into Parks 50 at an orange heat (first time didn't seem to take). Very tough even aft
  5. Just placed and received an order from John. Shipment was very quick and steel supplied in sizes I ordered. Haven't had a chance to pull it from the wrapping and use it yet, but on all accounts so far he appears to be legitimate.
  6. Personally I wouldn't worry about any potential harmonics, the other end of the shaft is under quite a bit of offsetting load from the belt tensioning system, so the shaft is hardly spinning free. I do like Brian's idea of putting a static guard in place on the shaft if you are really concerned. We have around a half dozen of the Grizzly version of this grinder in the group shop I sometimes attend, and to the best of my knowledge they have never presented a problem, even being used by beginners and students. If you cut it short (which I suppose you could always do with a hacksaw if you are
  7. Personally I have always had better luck with using forms with castable refractory. Don't have to be too complicated. I've used cardboard boxes lined with plastic bags, sonotube, sheet metal forms, foam insulation board, clay, and even vinyl sheet flooring. You could trowel on a slightly drier than normal Mizzou mixture, but you will likely have to do it in sections (a base for the back, then two or three for the sides). This may lead to separation inthe future unless you are careful with your installation. Wet Mizzou doesn't stick well to vertical or overhead surfaces. In an
  8. I have tried forcing a patina on some of my blades by fuming with boiling apple cider vinegar (do this outside if you can). As with any patination, the stock needs to be clean. Give it a try and see if it works for you, I find it to be a "gentler" etch than Ferric and more in keeping with aging through use.
  9. Working hard on a Sunday night. My hats off to you. Wrote back just now.
  10. Really like these, nice work. Let me get this clear though: You do the complete grind, polish, etch, and sharpen before bending the "hoop" at the back of the scissors to finish the piece? I assume you heat the back up with a torch to make that bend?
  11. Hard firebrick isn't actually designed to absorb heat, just to withstand it without breaking down. Because of it's thermal mass it does not act as a good insulator (like soft firebrick or the ceramic blanket that Welsh has in his well designed gas forges. The heavy thermal mass in the hard firebrick both absorbs a bunch of heat before it starts to re-radiate it back into the forge chamber (which is what is supposed to heat the bulk of your steel - otherwise you could just use a torch in air) and also conducts some of that heat outside the forge (where it does no good for your stock).
  12. I'm with Jerrod on this. Definitely recommend tempering, and also a stress relief cycle (subcritical anneal at well under the transformation temperature - 1250-1350 range) before heating up to quench. I was trained to let normalizing and stress relief cycles cool in air, not in a jig. Your jig may be cooling the stock too quickly. Good luck on the next one. Kitchen knives are tricky, but straightening during the second or third tempering cycle, as other's mentioned, has worked for me as well.
  13. Instrument makers used to color boxwood by fuming with Nitric Acid. Gives it a lovely golden glow and emphasizes the grain. Would be a fantastic addition to your piece, but I expect the blade would lose it's fine polish...
  14. John, Just be careful and don't get hurt. Send me a message when you find them and we can work something out. I'm in Rochester, NY, so not too far away, but am unlikely to head out your way in the immediate future. I guess we will have to ship.
  15. John, Well if you find it I'd be up for four to six 4' sticks in that length and between 1.5 and 2" wide. Thanks, Dan
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