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stuart davenport

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  1. Hey Charlie, you're braver than I am! I've done one water quench that didn't go so well at all. I had my grind pattern going edge to spine, just like yours. That was but one mistake among a few I made! For future water quench.... 1. If you are set on water quenching 1095, use brine over straight water. It is a "faster" quench in the sense that the salt helps to break up the vapor jacket, allowing a better contact of water to blade...that is how I understand it. I would also do an interrupted quench as well. 3 seconds into brine, then immediately into oil until ambient temp. Then temper. 2. Canola oil at 130°F will harden 1095 in thin sections (under 1/8" spine, thin edge) pretty well, for future reference. 3. Have grind lines running horizontally (tip to ricasso) instead of perpendicular (spine to edge). The grind lines at a thin edge (especially an edge that is apexed) is a huge target for a crack to promulgate. 4. Looks like you put an edge on that blade before quenching. Am I seeing that right? Best to leave the edge ~0.030" or more. 0.020" bare minimum. 5. A thin clay slip along the edge, as Brian mentioned, helps in the way that salt does in water. Breaks up the vapor jacket. A few notes, 1095 best hardening temp is 1475°F with a short 10 minute soak to allow the extra carbon in solution, if you have the ability to hold that temp in your gas forge. Normalizing needs only to be performed if the steel has been forged (and if it's heavily spheroidized...but most 1095 is fine spheroidized). Normalizing, by definition, is only done once. For 1095 that is 1600°F with an air cool. After normalizing, you can do a few "thermal cycles" to help "shrink" the aus grain, usually in descending heats with air cools, as in 1500°F, then 1450°F, then 1375°F, as an example. If you will be making a lot of knives in 1095 or especially W2 in the future, one of the biggest bangs for the buck is a fast oil quench medium like Parks 50 or DT-48. These are formulated to simulate the speed of a water quench, without the risks. Best $$ I've spent for the shop. You won't look back. Good luck on the next one! Let us know how it goes, if you would, and tell us what you changed for better success.
  2. Carbon aside (we are talking knife steel here anyway, so anything .6% and above), Manganese will be the biggest alloy contributor to how fast a quench needs to be. Chromium comes next. Generally, a steel with Manganese .3% and lower will require a fast oil. Get to .2% and lower, fast oil may not be fast enough. For example, W2 and 1095 are essentially the same steel, of course W2 has some vanadium for grain boundary pinning and a little bitty touch of Chromium....but 1095 has .4% Manganese and W2 has .2% Mn. This small variation is big when it comes to quench oils. Just ask "Jeff the Millwright" on Bladeforums how he figured that out. What may harden 1095 may not harden W2. A simplification.... alloy with .9% C/.4%Mn needs a fast oil to harden (1095). Alloy with .9% carbon/1% Mn will harden in a medium speed oil (O1). 52100 is another good example to look at. .3% Mn (less than 1095!). But why does it harden quite well in medium speed oil, and a fast oil is not needed? Because of the Chromium count of 1.5%. for more in depth explanation, search the term "hardenability".
  3. RA will be dependent upon austenitizing temp. According to Roman Landes and Kevin Cashen, a 1080 steel hardened at 1475°F with a short soak, and quenched properly, will have essentially no RA. 1095 can have RA problems, but again, drop the aus temp to 1475°F, soak, quench, RA should be less than 10%.
  4. Pferd files are my favorite (haven't tried Grobet, but I hear they are excellent). I use a 14" Pferd Chip breaker for rapid material removal. Simonds are 2nd in line, with their 14" Multi-Cut. NOS Nicholson files are excellent as well...but make sure they are NOS (new old stock). The new Nicholson files are being made in Mexico and Brazil, and QC is out the window.
  5. Your photos are just simply awesome, Austin! Great job with the camera! Nice pic of the bull nose! Cool snakes, if there is such a thing. Your time lapse of the stars is excellent, as well as the Milky Way panorama. The Hill Country is beautiful, for sure, and you capture it well.
  6. !.2519 is one of my favorites. Not a steel I would be drawing the spine with, or edge quenching for that matter. But that doesn't mean you can't or shouldn't. This is a steel that does exceptionally well with thin geometries and low edge angles at high hardness like 64HRC+. Best for kitchen knives, hunting knives. Basically 52100 with some added wear resistance with the Tungsten. Pearlie nose should be about the same as 52100. 3 seconds or so. The Tungsten count really isn't all that high. 1.3% W is equivalent to about .33% vanadium, due to atomic weight. Side note: 1.2442, very close in comp, has 2% Tungsten, which equates to around .5% vanadium. Cru Forge V has .75% vanadium. That would be equivalent to 3% Tungsten.
  7. Matthew said it. Quench to form martensite, then place in oven at 1200f for an hour or so. This will spheroidize the cementite.
  8. Yeah, the 300 series would offer more corrosion protection, but the 416 works!
  9. Not just aesthetics, but function too. Because the stainless is soft, it's much easier to thin the knife when needed. Does offer some corrosion resistance, even tho not fully hardened. At least that is my understanding.
  10. Blue 2 should not have a pattern to it, of course. The bar you ordered should have been a solid billet of Blue 2, but I am wondering if the package is mislabeled and they sent a bar of suminigashi instead. However, usually the pattern of suminigashi is a series of "sort of" straight lines that run from tip to ricasso. VERY VERY strange. Beautiful, indeed, but I have no idea what you have there. I've worked with mono Blue 2 before....it looks just like any other steel when finished. Needs a VERY fast quench, or auto hamon may show up, especially larger knives. I'd get in contact with Dictum.
  11. How a blade flexes has nothing do to with the steel or how hard it is. It is dependent solely on geometry. How/when the failure occurs is a different story.
  12. The 10xx series steels like 1080, 1095, have a pearlite nose of less than one second....so plate quench is out. Once the PN has been beaten in an oil or water quench, then the plates could be used during Ms-Mf to help with warp issues.
  13. Gabriel, you're going to wonder how you did without the P50! It is indeed wonderful stuff! 1095 and W2 both are very very shallow hardening, so you really do need a very fast quench. And as you see, water can be risky. I always recommend a brine solution over straight water, because the salt helps to break up the vapor jacket that forms around the blade in a water quench. Also, adding an extremely thin clay slurry on the entire blade helps to break up that vapor jacket as well. The only steels that I can actually recommend a water quench (Brine) are the Paper steels from Hitachi Yasugi. White, Blue. Their impurity count is low, and alloying low, to allow for successful water quenches. And just for future reference, actual critical temperature for 1095/W2 is around 1475F or so. The magnet will start to release from steel around 1350 on the way up in temp, and will totally not stick around 1414-1425. When the P50 comes in, tell us how you like it!
  14. Couldn't have said it any better than Jarrod did! Soak times are usually not recommended, because they aren't needed, on eutectoid steels. Like 1084 or 15n20. With those steels, hit the target temp, let the blade equalize (I guess technically we could say soak it for ONE minute), then quench. However, with HYPER eutectoid steels like W1, there is extra carbon (and it is tied up with iron....making the iron carbide cementite). How do we heat treat with a steel that has extra carbon? Well, the first thought is to go higher in temperature. And yes, this can put more carbon into solution. But by going higher in temp (talking 1530°f plus), not only will the martensite not get any harder, you'll have TOO much carbon in solution, and this translates to retained austenite. Like A2 for example. Austenizing temp for that steel is 1750°F, and in order to achieve max hardness by RA reduction, a sub zero or cryo is a MUST. Plus, you'll likely have your aus grain blown way too big, especially if there are basically zero alloying ingredients in the steel....like W1. A2 has alloying to help prevent that. W2 is a bit better than W1 in that regard, the Vanadium in W2 really helps to pin the grain boundaries, so little to no grain growth is noticed, even at higher hardening temps. But RA still is a problem in that situation. We do good to remember that carbon in solution is not JUST temp dependant, but TIME dependant as well. But MUCH more temp dependant for sure. So in order to keep our aus grain small (since we don't have cool alloys to help us with W1), we do extended soaks at a somewhat lower aust temp. This allows carbon to come into solution without grain growth, without retained austenite. Edited to add....I forgot that W1 should have a little V in there as well. Even just .1% is enough to help prevent grain growth.
  15. That TTT chart for W1 speaks quite a bit! You've got way less than one second for your quench medium to do it's job, as Jerrod mentioned...just like 1095 and W2. Warm canola oil at 130°F will work in a pinch, but likely will not provide max hardness, especially on stock thicker than 1/8". A brine solution, followed by a warm canola oil, is a pretty safe way to beat the pearlite nose on these steels. 3 seconds into the brine (distilled or purified water with a 10% salt solution), and then finish the quench in 130°F canola oil. FAST commercial oils like P50 simulate the speed of water without the risk, and if you're going to be using shallow hardening steels quite often, it is your greatest friend (or similiar oils like DT48). As a side note...if you ever work with the Hitachi Yasuki steels, White Paper and Blue Paper, these are about the only steels that I would recommend an actual brine quench. Their Mn count is so low, you must have a super fast quench, and because these steels are so pure, brine quenching is not as risky. But I digress. Forged W1 heat treat, a good start would be to do as follows (I like recipes. The "why" can be asked at any time and I'd be MORE than happy to talk steel and heat treating!) Since we have forged, we MUST normalize first. And then thermal cycle to take care of aus grain. W1 recommended normalizing temp for a 1.0% carbon content: 1600°F, soak for 10 minutes, air cool only To thermal cycle: usuall three cycles is plenty, some guys go thru a dozen or so (way overkill to me, and can reduce hardenability. Play around with temps and number of cycles if you like) 1550°F for 10 minutes, air cool 1500°F for 10 minutes, air cool 1450°F for 10 minutes, air cool or quench 1400°F for 10 minutes, air cool or quench Notice "air cool or quench". I think it has been shown in Cr bearing carbon steels, like 5160 and 52100, that quenching refines grain slightly (very slightly) better than simply air cooling...but with risk!!! I do NOT do multiple quenches on any steel, usually. Air cool in still air refines grain structure quite well without risks of distortion or other issues that cannot be detected visually. Simply put....it's YOUR shop...YOUR call to quench a few times or just once during hardening. To harden: 1475°F for 10 minutes, quench (brine) or (brine for 3 seconds then oil) or (Parks 50 at room temp) or (canola at 130°F) Once able to handle at room temp, you can check your file test, but be sure there will be a decarb layer to get thru, especially if unprotected during all that cycling. Max hardness after quench will be 66-67. Temper at 300°F one hour for 63. Temper at 400°F one hour for 61. Temper at 500°F one hour for 59 (Blue brittle range....be careful here) (numbers provided by Buffalo Precision) At least two temper cycles.
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