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Dan Hertzson

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Dan Hertzson last won the day on November 22 2023

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  1. This is why you need to avoid unproven online material sellers. Been saving this " stabilized " burl for a special project. Cut a slice off two blocks today before drilling for a Wa handle, and glad I did. Here are the results (first shot shows lack of acceptable penetration).
  2. Thanks for the link. That socket is incredible.
  3. I have hot forged silicon bronze at very low temperatures (dull red in a dim shop at most). Get it up to an orange and you are asking for trouble, but on the plus side it is pretty soft at the right temperature. Like copper and brass it can be cold forged, but you have to anneal it often. These were all hot forged from a silicon bronze survey marker I got from the transportation group at work (including hot punched and drifted holes):
  4. Couple of suggestions in addition to the excellent ones already given: In addition to drilling pin holes in your blank (with a drill press if possible) before hardening, make sure your handle section is really flat. Much more difficult to sand flat after the blanks are hard. Before hardening, sand profile along the length of the edge and spine. Less likely to start cracks if there aren't scratches going perpendicular to the edge. Take care when quenching to agitate the blade in the fluid in either a "stabbing" or "cutting" motion, not moving the blade from side to side (direction of the flat of the blade). Quench in a well ventilated room and wear long sleeve welding gloves. Get the blank quickly from the forge to quench tank once up to temperature. The tip and edge that you want to harden will cool quickly. Practice the "dance" with cold stock so you get all the motions correct and set the stage properly. Be careful not to let the quench media get too hot. You don't want to be close to the flashpoint when running multiple blades. Fireballs may make good television, but aren't much good for anything else. Use good, secure tongs to hold the blank when quenching. Not only does it suck to have to fish for a blade in a quench tank, but the tip can crack if it is hard and hits bottom. Use a steel quench tank, not plastic Be prepared for warpage, there are a variety of tricks to use if that becomes a problem, but too much to go over here. Don't leave the blanks in the heat treat chamber too long. Let it get up to temperature, then heat steel. It is easy to overheat (particularly tips and edges) and get unfortunate grain growth. After the quench, let cool to room temperature on a lightweight, insulating kiln brick, then get into tempering oven ASAP. Be prepared for plenty of hand sanding after heat treatment. Good quality sandpaper will really help. Finish front edge (closest to ricasso) of scales before gluing onto blade Use good quality, "new" epoxy to glue on scales and don't over clamp and squeeze all the epoxy out of the joint. Rough surface of micarta to at least 120 grit to aid in retention. Good luck, sounds like a fantastic project for the boys (and their fathers).
  5. Please be particularly careful quenching the barrel. Dumping a red hot open ended tube into a quench tank is a recipe for creating a spray of whatever fluid you are quenching in. I am really not familiar with color case hardening processes, but if you are going to dump a hot tube into cold water the fluid inside the tube has a tendency to flash to steam. This can be kind of surprising at the other end...
  6. Please don't do this without having someone standing by for at least the first couple of tries. If you are "inventing" your own equipment styles you never know what may go wrong. Most tools have evolved over time by tossing the styles that have failed or were inefficient. Not dissing you at all, just recommending safety. I forge my tongs, so it really doesn't matter that much to me if the starting stock is round or square. I assumed you would be doing the same for the bit and boss section at least. Tubular reins (out of pipe) may give you a bit more diameter to hang onto at the same weight and bending strength. Along with easy availability at a plumbing shop, that is why I recommended same. You might also want to consider some kind of counterbalance. The split function lifting and pouring tongs that Alan linked in the video seem like a very clever option to me, and the video takes you through design and manufacture.
  7. I wouldn't use aluminum. You could go with 1" schedule 40 pipe and oval it up (possibly even 3/4") for the reins (arc weld to boss and bit). I would certainly use at least solid 3/4" round for the boss and bit section and forge a little thick (some 5160 spring stock might be a good choice, but don't quench). The last thing you want is for the heat of the crucible to distort the bits during use. 20 lbs at 3' extension is a bit of torque. Hope your wrists are up to it. Good luck
  8. Its a nice little knife. If you are looking for critique, there are a couple of minor points that I think could be improved, but it is certainly acceptable as is. Minor enhancements: I would consider wet sculpting the sheath to more closely match the blade profile and provide a "tighter" fit. Currently it looks a bit generic. I'm not a big fan of the machine finish on the blade. IMHO, one of the big differentiators for a custom hand forged and finished knife is that hand rubbed satin finish. The top section of your harpoon clip shifts from being straight to follow the curvature of the knife edge. Aesthetically I would prefer to see it continuing straight.
  9. Think I would probably just carefully heat it in position with a rosebud and bend it back into shape by driving in a drift of the correct size. With all that thermal mass in the bracket I suspect you could get the offending section heated before the rest of the assembly gets too hot. Might be a problem if you have high density plastic guides though.
  10. I also got one of the Beaumont SGA and have adapted it to my TW-90. Nice piece of kit.
  11. I have always used an old toothbrush for this. Seems to work pretty well and is better than tossing them once they start to show some wear...
  12. All of them are nice, but the form and flow on the replica is particularly sweet.
  13. OK, you are approaching this as an industrial designer, so I will respond as such. I apologize in advance if it seems my comments are overly harsh, but I'm hoping that you take this as an attempt at constructive criticism. As an industrial designer you need to improve your drafting skills (top view and side view of handle don't line up correctly, bolster isn't shown in top view, "top" of tip in side view doesn't show transition from false edge at spine to taper to point...). You also need to better understand how things are manufactured (screwed on pommel is much too thin for effective threading - and may be difficult to align given it is the main mechanical system holding the knife together, there is no indication on how the bolster is attached, the flat ridge won't look like that unless either some milling is done on either side or the overall thickness is greater and bevels are very precisely ground...). I would look into learning a bit more about ergonomics (or at least use some existing knives so you have a better understanding of effective handle design and blade proportions). To answer your most recent question, I don't see any reason to remove the tip (but you should certainly reconsider the two teeth on the spine and the hole in the bolster. The mass balance is a little questionable as well. This will be very forward heavy as currently drawn. At the moment you have a blade that will work well in a video game, not in real life. Again, I strongly recommend that if you aren't going to learn how to do any actual bladesmithing, you at least make some full size mockups of your designs in carboard, soft wood, foam core, or similar. You can knock out a proof of concept design with an x-acto knife and hot glue in an hour or so that will really help inform your future efforts.
  14. Doug, Absolutely, in fact that is what Emiliano used for his demo.
  15. Good question. The socket was made separately from a sheet of ~3/16" thick wrought iron which was then forged to the assembled spear blank. The core of the blank needs to extend past the blade around 3/4" with a stub tang. This then gets hot fit into the top of the pre-made socket right before forge welding the final assembly. Note that the transition between socket and blade becomes much easier if you have the core section of the blade, at least, slightly larger than the diameter of the OD of the front of the socket. That was the major mistake I made in my piece, and resulted in me flattening the center of the spear blade rather than having the full central ridge I had been intending. A flattened center is still acceptable and even traditional, I just had to pivot during the grinding to maintain proper distal taper. If you use wrought iron for the socket be careful of the "grain" orientation of the wrought. Unless extremely well refined, it should be set to wrap around the circumference rather than longitudinal. This helps to limit splitting along the socket length with the relatively tight bends required. Some of the smiths in the class elected to use forged black steel pipe instead of forging a socket from sheet when they had difficulty with the latter. This was a lot simpler, and afterwards it was hard to tell the difference. A decent swage block or bottom swage is your friend for this. I brought the attached pattern with me that I drafted up in advance (Print to scale on a 11 x 17 sheet. I'm not sure if the server will accept attachments, I will try to also include an image). Please note the overlap "tab". I forged bevels on each side of the socket to gain a little extra width for that overlap and made sure the "thick" sections overlapped, and the bevels served as scarfs. The socket should be forged a little smaller in diameter than the eventual plan to allow for some adjustment as the process goes on. I ended up using a 5" socket length due to the heat treat oven restrictions. Please note that this socket design was made to match my bick and mandrel. Feel free to change to suit yours. Overall spear head length, including socket, is just over 17" if I recall correctly. Look forward to seeing yours. Socket template.pdf
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