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Michael Kemp

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Michael Kemp last won the day on May 2 2016

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  1. OK then - my grain is somewhere between your two examples. As mentioned at the top of this thread, after the forge welding I assumed I had huge grain size - and for the first set of 3 normalizations started pretty high: 1650f then 1600f then 1575f. Then an anneal at 1475f and into in pre-heated vermiculite. Then ground to final shape. Then 3 more normalizations all at 1575f +- 7f for 5 minute soak - air cooled in still air to where I could hold the blade in bare hand. This is the grain size I got. Any helpful hints are appreciated!!!
  2. Heya all - entertaining reading. While I *am* using a forge rather than a Paragon or Evenheat - the blade was normalized set vertically on it's spine on a bridge across the forge above the burner. I use a pyrometer mounted near the center top of the forge. The kiln shelving bridge and blade support were at forge temp. Visually speaking left and right side of the forge were the same color. I soaked the blade for 5 minutes on each normalization once the blade visually reached the forge interior color. That said the blade is friggin' thin (0.062" spine at the point that the warp reappeared -
  3. Update: I've tossed the chef knife in the "oops" drawer. I was down sick for a few days - so this was about a week ago. I had it straightened - but while cleaning up the bevels I let part of the blade get hot. Not hot enough to color - just hot enough to warn me ?200f? - and the warp returned to that section of the blade. I'm making up a couple of new Damascus billets - but will only be making small knives until I can get some hands-on mentoring. David Lisch is 4 hours away so I'm watching for him to post his next Damascus class - I believe he's in the process of moving. John Emmerling is
  4. Thanks Niels - I've always taken it out of tempering and used a 3 point jig in a vice... I *have* to remember to try your way next time... and despite all efforts, I'm confident there will be a "next time." ;-]
  5. I've been having a side conversation with John Emmerling about this - and he also grinds after heat treat. And when he hardens he quenches in oil for 8 seconds, then clamps between aluminum plates. So the warping issue isn't just me... I just can't treat Damascus like it was 5160.
  6. Good points Joshua - and if Ed Caffrey warns about 1095 Damascus warping - well then.
  7. Matthew - you may be right about thin blades - they've sure given me fits. As for extra thermal cycling impacting hardenability, I believe it also improves toughness - so kind of a trade-off. I've been getting around 57 Rc on my Damascus kitchen knives which I consider appropriate. Hrisoulas noted in one of his books that Damascus tests low in Rc - and heck - my Wusthof knives test the same. But yah, the only real "cure" may be to harden a profiled but un-beveled blank before grinding and sacrifice more Damascus to the grinding gods. I'll try flipping sides more during grinding (an
  8. Peter - good queries. I *believe* that the forge temp is even - but that may be the culprit. I'll be building a new forge with better temp control at austenitizing temps - so in a month or two we'll see if that's the culprit. For cooling in "still air" I have a rectangular chamber of firebricks with one end open - the floor is those soft refractory bricks - and I have a couple of fragments of kiln shelving that barely contact the blade to keep it vertical. Hmm. As for thinking of "anything that might have made" heat gradients - I'm at wits end (not that I'm all that long in the wit
  9. James - the blade sat vertically in the forge - and I'm of the opinion that the heat in the forge was even... but that could be an issue. It did not warp in the initial set of 3 normalizations and an anneal. Of course it was slightly thicker steel at that point. At any rate it was straight when I started grinding (and when I finished grinding). Maybe it had something to do with my grinding techniques - but I thought I worked on front and back about equally. Hmmm.
  10. I'm supposed to know these things, but obviously I don't have it down yet. My current 8" chef knife started warping in my final set of normalizations?!? Any insights welcome (even those I've heard or read a dozen times). Blade history: Billet of 1095/15N20 I forged - several hundred layers (theoretically 700+ but I know I burned off some and ground off some layers between cutting & stacking for each round). Forged pretty much to shape & thickness - bevel & distal taper. Mainly using drawing dies on a press - some flat dies on power hammer and some hammer & anvil wor
  11. Bits & parts - the guy at the propane shop sold me on a fail-over switch for 2 propane tanks - hook up both, open both, set the gizmo to one tank and the flag goes green and it runs off that tank until empty then fails over to tank 2 and the flag goes red. You set the valve over to tank 2 and replace tank one. Repeat as needed. I'm hoping it works as slick as advertised in practice. I've got one hose & bell in the truck to remind me to pick up proper connector fittings.
  12. Kenon - looking forward to seeing what you come up with. At this point I think I'll build a couple of ribbon burners set up for forge welding temp... then play with reducing the pressure until I get nervous - if it *doesn't* get down to austenitizing temps then I'll build a couple more burners with fewer holes that I can swap in as needed. I certainly don't want to make a pipe bomb. I hope you folks are patient with me - it always takes me a LOOOOOOONG time to get a project done. I haven't even got the steel for the forge shell yet. Or the Inswool & Insboard... just Kast-O-Lite, some b
  13. Joshua - thanks! So even with the ball valve and gate valve choked down for heat treat the flame never creeps back inside the ribbon burner? Excellent! Thanks for the info. And no - I don't expect to take the forge down to tempering temps - I've got an old kitchen stove oven for that (with a deep tray of sand that I put the blade in to even out the temp swings).
  14. Joshua/Wayne - Thanks guys - I've visited John's shop and watched the burner in action - impressive! Welding heat is obviously no problem - HOWEVER - I'm concerned about running a burner with that many holes down at heat treat temps. I'll be choking the air with a gate valve and the propane with a needle valve. Like I do on my current blown burner. When I choke it waaaaay down on my black-iron-pipe blown burner the flame will flutter back up the tube - which is annoying but not dangerous. On a ribbon burner I'd think that would turn the gas/air mix area of the pipe into sort of a pipe
  15. I'll be building a ribbon burner powered forge next. It'll be 24" deep so I can heat treat brush blades (I don't have a place to put an Evenheat or Paragon if I bought one). It must perform at forge welding temps and at heat treat temps. Preferably built so it can be disassembled and reassembled at a hammer-in. Better protection of the insulating wool than my current forge. Dual 20# propane tanks to humor my bad back and allow tank swaps during forging. I've been happy with the bottom of my current forge: an inch or two of kitty litter on an inch of Insboard. I want the burners below the
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