Andrew Colglazier Posted April 18, 2016 Share Posted April 18, 2016 The rasps I have harden in brine, but warp, even when normalized. They do not seem to harden (or warp) in oil. What to do? Does stock removal vs forging make a difference in how rasps behave when quenching? Any help welcome! Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 18, 2016 Share Posted April 18, 2016 Are you overheating them before quenching? Have you though of buying some Parks 50? Details of your process? What shape/form are they? Are you trying to make a rasp into a blade or a bar of steel into a rasp? Link to comment Share on other sites More sharing options...
Andrew Colglazier Posted April 18, 2016 Author Share Posted April 18, 2016 Good questions - I don't know if I'm overheating. I'm going by color and demagnetization. I've been using brine with forged blades, with a small amount of warping, but these blades seem to be more prone to warping (stock removal) Annealing - grinding - normalizing x 3 - quench. I'm making knives. They have been large single edge blades. Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted April 18, 2016 Share Posted April 18, 2016 What is you actual process? How do you anneal, normalize, etc...? Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 18, 2016 Share Posted April 18, 2016 Are you going thinner on the blades doing them stock removal before heat treat than you were forging them? Link to comment Share on other sites More sharing options...
Andrew Colglazier Posted April 18, 2016 Author Share Posted April 18, 2016 26 minutes ago, BIGGUNDOCTOR said: What is you actual process? How do you anneal, normalize, etc...? Anneal - heat to non-magnetic, bury in hot go get ashes and allow to cool overnight. Grind with belt grinder. Normalize - heat to non-magnetic and let air cool 3x. Quench - heat to non-magnetic, quench in brine (or oil). If oil, the oil is warmed to +- 130. Temper - place in convection oven for 1 hour at 450. Allow to cool to the touch, repeat 3x. The blade will warp but harden in brine, won't warp or harden (file test) in oil. 30 minutes ago, ThomasPowers said: Are you going thinner on the blades doing them stock removal before heat treat than you were forging them? Actually the forged blades are somewhat thinner than stock removal. Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 18, 2016 Share Posted April 18, 2016 How hot are they getting during grinding? Link to comment Share on other sites More sharing options...
Andrew Colglazier Posted April 18, 2016 Author Share Posted April 18, 2016 1 minute ago, ThomasPowers said: How hot are they getting during grinding? I grind bare handed. If they get too hot to touch, I dip in water. Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 18, 2016 Share Posted April 18, 2016 Well you have covered most of the items I check when things start warping on me---any difference in brand of rasps? Link to comment Share on other sites More sharing options...
Andrew Colglazier Posted April 18, 2016 Author Share Posted April 18, 2016 5 hours ago, ThomasPowers said: Well you have covered most of the items I check when things start warping on me---any difference in brand of rasps? Yes, could be the problem. These are Safecut and no name. I usually use Heller. I will move this to the knife section, since you didnt notice it Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 18, 2016 Share Posted April 18, 2016 Heat the tang of the rasp like you would the whole thing and quench it in water (just the tang). From there, do not temper but put it in a vice with the hardened tang sticking out. Give it a tap with a hammer. If it doesn't break but bends you've got a case hardened steel. If it bends but is very tough then it's likely 4140 or something similar. Either of those outcomes put those rasp in the art department and not for knives. Oh, wear your safety gear. Don't want to loose an eye to flying metal. While I shy away from rasp I did have a good experience with a Heller. Link to comment Share on other sites More sharing options...
Andrew Colglazier Posted April 18, 2016 Author Share Posted April 18, 2016 19 minutes ago, jmccustomknives said: Heat the tang of the rasp like you would the whole thing and quench it in water (just the tang). From there, do not temper but put it in a vice with the hardened tang sticking out. Give it a tap with a hammer. If it doesn't break but bends you've got a case hardened steel. If it bends but is very tough then it's likely 4140 or something similar. Either of those outcomes put those rasp in the art department and not for knives. Oh, wear your safety gear. Don't want to loose an eye to flying metal. While I shy away from rasp I did have a good experience with a Heller. Yes sir. Hardening isn't the problem. They harden in brine, but warping is a problem. If I quench in oil, they don't warp, but don't seem to harden either. Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 19, 2016 Share Posted April 19, 2016 Have you done this test then? Some are made from 4140 then case hardened. This steel will harden but will not snap clean or easily like high carbon steels. As a rule I don't mess with rasps too often. I've been burnt (figuratively) by name brands that were case hardened 4140. Link to comment Share on other sites More sharing options...
Andrew Colglazier Posted April 19, 2016 Author Share Posted April 19, 2016 2 minutes ago, jmccustomknives said: Have you done this test then? Some are made from 4140 then case hardened. This steel will harden but will not snap clean or easily like high carbon steels. As a rule I don't mess with rasps too often. I've been burnt (figuratively) by name brands that were case hardened 4140. I haven't, but I will now. I appreciate the tip. It will no doubt save me time in the future. Thank you! Link to comment Share on other sites More sharing options...
swedefiddle Posted April 19, 2016 Share Posted April 19, 2016 Good Morning Andrew, Brine = Quenches the fastest Water = Quenches Fast Quenching Oil = Slower than Water. Type of Quenching Oil means Quench Rate differs Hardness depends on how many ???? degrees of Quench of the Steel per second. This is considering, using the identical Steel for comparison. Water makes steam pockets at the surface of the Steel. You can hear it Squeal. You must keep it in motion to break down the Steam pockets. Quenching Oil makes pockets as well as Fire. Read, wear your respirator!! All being consistent, the only thing you are changing is the Quench Rate. You can straighten by using a carbide tipped Hammer. Cross the Blade to take out a bend, Length of the Blade to take out a Twist. You didn't say you were quenching sideways or Lengthwise. Another day, above the Dirt. Gotta Love It!!! Neil Link to comment Share on other sites More sharing options...
Nobody Special Posted April 19, 2016 Share Posted April 19, 2016 It's only a guess, but you might be grinding too thin prior to heat treat, I've had that cause warping before. I don't have the expertise at blademaking that some of these people do, but I do better when I leave some meat on it, and do the last grinding and finish after hardening and tempering...even if it slows it down, and I have to be careful about not overheating the blade and wrecking the temper. As Moxon said, "If a true edge is yours to win, forge thick, grind thin." Link to comment Share on other sites More sharing options...
Biker Bo Posted July 31, 2016 Share Posted July 31, 2016 I just H.T. a rasp Bowie last weekend. Normalize 3 x. 1600 cool in front of fan. 1500 cool to black in still air 1425 cool to black in still air. Heat treat Put it in the forge at 1425 and moved in and out to bring up to temp while forge temp was rising. Let it soak from 1450 until temp reached 1500 then did an interrupted quench. Quench in 130° canola oil for 4 seconds pulled out for 3 then back for 4. Clamped between two aluminum plates while still smoking. It's still warm enough to pull any warp out without breaking at this point. Then two temper cycles at 425. I have a gas forge with a muffle pipe and type K thermocouple. Took a good edge but I need to test more before finishing it up. This was a stock removal knife. I followed the steps as if it were 1095. Hope this helps. Link to comment Share on other sites More sharing options...
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