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Alan Longmire

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Everything posted by Alan Longmire

  1. The way that works is (keeping in mind what I said about sounding like I know what I'm talking about) that grain size is directly related to hardenability and depth of hardening in a simple shallow-hardening steel like 1095. The smaller the grain, the more shallow the hardening, and thus the thinner the depth of hardening. As I understand it, when you get that kind of auto-hamon in an oil quench, you are teetering on the precipice of having to go backward in time to beat the nose of the TTT curve and achieve hardening. You know, that thing where you have less than one second to get 1095 from above 1425 degrees F to below around 1000 degrees F? That's assuming a grain size of 9 or 10 (units don't matter, the larger the number the smaller the grain). Say you refine the grain to 13 or 14 (industry stops at 10), you have now moved the nose of the curve closer to the Time = 0 axis of the graph. We had this happen at my February guild meeting. A new guy had a 1095 blade about 3/16" thick, not bevelled, that he wanted to harden. He had done numerous normalizing cycles, like eight or ten. I fired up the club gasser and guided him to decalescence, whereupon he quenched in fresh warm canola. No effect. Didn't work the second time either. We were thinking about going to water, but the only water we had was ice cold and that seemed like a bad idea, which is when I realized that we'd probably refined to grain to the point that it was physically impossible to harden it with the setup we had. The solution? Take it back up to critical, go a little hotter, hold for one minute to grow the grain a bit. Quench. And bam, it hardened perfectly. Once he gets it ground it will probably have a bit of auto-hamon in the center of the blade. I know about this because I know another guy who cycles 52100 so much that it has to have a water quench or it won't harden. And that's supposed to be impossible...
  2. These are easier: https://www.ebay.com/itm/Char-Broil-2-Pack-17-75-in-Adjustable-Length-Stainless-Steel-Tube-Burners-4507/123712238789
  3. I was in physics before I was in archaeology, remember.
  4. The last time I thought I knew something completely I was 18. The older I get the less I'm sure I know! I just know how to sound like I know what I'm talking about.
  5. Now that's just diabolically clever!
  6. Nope. VFD requires a 3-phase induction motor. Trying it on a single-phase with the start capacitor removed would give you one third of the desired impulse. If you have a VFD now, try this: Get it running, and turn the speed control down to 5% or so. Notice how the motor is now "stepping?" As in, it goes click every time the output from the VFD kicks in and energizes one leg of the three in the motor, rotating the armature 1/3 of a rotation? IF you tried it with a single phase motor you lose two of those legs, and the motor can't move fast enough to stay running. Single-phase brush-type motors can be speed controlled by variable resistance, like a router speed control, a variac, or even a dimmer switch for low voltage stuff. That's how you can use a vacuum cleaner blower on a router speed control for a forge blower. Unfortunately, the 1hp and larger motors we use on grinders are brushless and need the full current. Brian can explain what I got wrong about this later, but that's the short and almost sort of right version.
  7. Overkill is almost enough, eh? The easiest way to make one is to get an old water heater shell or other big metal tank, cut one end off to make a door, then get a couple of long burners off a gas grill. Plumb the burners in exactly like a gas grill, holes in the bottom of the tank and all. Make a rack of some sort to hold the blade near the top, with vent holes in both ends of the tank and maybe a couple on top if you have trouble keeping an even heat. What you're after here is just a big gas grill. No insulation needed. If you want to go slightly more difficult, Jesus Hernandez's design (and the one I have, obtained from Dennis McAdams) uses a 1" black iron pipe running the length of the tank, one end capped, and one end connected to a Ward reducing T- type venturi burner. (your turkey fryer plenum would work fine too). There are 3/64" holes drilled every inch down both sides of the pipe to make a long thin grill burner. You're going to need an accurate thermocouple to tell your heat no matter what. Remember for swords you generally want a full spring temper. That's going to be just above the blue-brittle range for your steel, anywhere from 575 to 800 F depending on alloy assuming simple or low-alloy blades. Now then: Your materials stockpile will make an excellent electric tempering oven, those do need insulation to work well.
  8. In addition to that link Joshua posted, I use a 2" serrated rubber wheel for narrow fullers, and a 6" for wide ones. Look at Sunray polyurethane and AMK for cheaper wheels.
  9. Looks like auto hamon to me! That shows you normalized very well indeed. And got the quench just right.
  10. But then I'd have to tell her what I really paid for stuff! Kidding, she knows.
  11. Mine asks "What will that let you do that you can't do with what you have already?" I have had to get creative a few times with that one, but once she's satisfied it will allow me to do things either previously impossible/too heavy/significantly faster/easier it's all fine, provided the first thing I do with it is make her something fancy.
  12. The smatchet has a heavier pommel and thicker blade, for one, and the overall shape is a bit different. Geoff, I looked at that site too, and there do seem to have been several variants over the years. That 1.5lb weight with a heavy pommel would suggest 1/4" as a maximum, allowing for distal taper which nobody mentions. Being wartime production, maybe they didn't have any taper? Might be worth a shot to do stock removal practice on some 3/16" plate and see what you end up with. The one I saw in person was at a gun show when I was maybe 20, so that's long enough ago that I certainly could be misremembering. There's been sleep and whisky since then...
  13. Should be able to. Not bad on the fuller. That's why I replaced one of the steel idlers on my grinder with a rubber one. You get a much better finish.
  14. Planning for Ashokan! We shall see how travel goes in the next few weeks...
  15. I've only seen one in the flesh once long ago, and all I remember is that it was thick. Like 5/16" or so, maybe more. Can you take the length, width, and weight and use a formula to figure the thickness? I know it's iffy without knowing the grip and guard weight, but if you know the weight you can get the volume, which will tell you thickness. Minus the bevels, so it's complicated...
  16. This is inevitable, which is why I don't ever run the steel all the way to the eye. The other thing I run into is that the much harder steel, if the edges are left square like that, will cut into the iron rather than weld to it, leaving a really thin nick running the full width of the front of the eye. I think some of them were fullered, or at least stepped a little, at the front of the eye. A right bugger to lay out, but it looks good when it works. As I found with that poll-less 18th century thingy I did a couple of months ago. That three-piece poll you have looks like many I've seen, and is a great way to get a thick poll/thin eye. And I like the wire. I very rarely tack-weld stuff, it just feels wrong to me. I have, however, used a rivet to hold parts together for welding. The rivet then becomes part of the welded joint and disappears. And I feel your pain, literally! That axe I mentioned above was forged from 1/2" x 2" and darned near killed me. Keep it up, sir! What we need to do, although I can't bring myself to do it, is to cut a slice lengthwise off an old one from poll to edge, then polish and etch it to see all the weld lines and the flow of the iron grain that indicates fullering. We sort of did something similar to a small 10th-century Viking bearded axe head from a river in Lithuania in the name of science a few years ago. It was a ball of rust, but the owner agreed to sandblast it and spark the edge and the back of the eye. Sandblasting revealed the beard was formed by pulling the bottom of a thick bar in one direction only, the eye weld was asymmetrical just as in James Austen's Dane Axe tutorial, and the whole thing was a medium-carbon natural steel similar to what a good smeltmaster can make in a short-shaft furnace if he's really paying attention.
  17. I think Brian is right on. Now, if you had little raised spots, that would be bad. As it is, I think it's just that you have shallow-hardening steel and the one you hardened from full thickness isn't quite as hard at depth. If the manganese level is below 0.3% and you don't have any other alloying elements that promote deep hardening like chromium, molybdenum, or tungsten, you will only get full hardness for less than 1mm from the outer surface. This is not a bad thing, the core will be very tough. And it's only a point or two on the Rockwell C scale. As in, your full-thickness one could end up with an edge at Rc55 while the one that was pre-bevelled may be Rc59 or so. In short: shiny good. blisters bad. As in, blisters mean you have to redo your whole HT process. Shiny means you got it right. I get that effect on W2.
  18. Typically you do those scrolls without a vise anyway, freehand on the anvil. Yours look good, except for the putting-the-pointed-bottom-in-the-wrong-place part. Hearts are harder than they look to get even.
  19. Bravo, sir! I should really do that too. I will note that in the course of my 30 years as an archaeologist I have seen two pre-1860 axe heads that had lost their steel edge. On both, the broken weld showed there was only an inch or less of steel inside the iron cheeks. One of these was in Mammoth Cave, and the other had been carefully hidden under a rock, probably in an attempt to avoid parental wrath.
  20. Some of the nicest rasp knives I've seen!
  21. Dammit Owen, I keep trying to find excuses not to come over for your hammer-in, and you and Petr keep posting these masterworks that get my beard smoldering again... Thank you for that, I have been in danger of losing sight of what brought us all together. These last few collaborations you have posted remind me of why we started this whole divine craziness, and that I have withdrawn from it a bit over the last couple of years. That doesn't mean I'm going to turn up on your doorstep in May, but never say never! And I hope the first part of that verse is on the other side of the blade!
  22. Yep. I'll be watching this one.
  23. The second shadow hamon is called utsuri. Hard to tell if that's truly what's there with rhe damascus going on, but most likely it is. I like it, especially the plain antler.
  24. We all have days like that, it's just part of the process. Still annoying, though.
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