Josh Dabney
Moderator
I thought I'd start a new thread on this even though this is the same blade from my hamon attempt thread.
Having recently got Parks 50 I'm working our my HT as it applies to Aldo's 1095 and want to achieve full confidence that I've got my HT nailed both as a challenge to my own abilities and a service to my customers.
This blade was created as a test blade but having been quenched 3 times (twice for hamon and finally fully hardened) it's not what will be my final recipe for this steel but I wanted to put it through some paces and see just what it would do then break to check grain structure.
I tempered at 400 2 hours x2
I finish ground the blade to .017 give or take .0005 then convexed the edge and sharpened on stones.
Throughout this testing I've realized that I'm not 100% confident in reading what the blade is telling me as it applies to HT.
I am very interested at this point of better testing methods with more meaningfull results so I'd LOVE to hear suggestions.
1. I tried "brass rod testing the edge on the corner of a brass bar but couldn't get the edge to deflect and the blade bit into the brass a bit. So now I'm thinking that the edge is still fairly hard at a 400 degree temper and perhaps thinner edge geometry would be better.
2. Whittled an chopped a little on a preasure treated 6x6. No damage or dulling
3. Chopped on an old dry antler as hard as you can chop with a 4" blade and no handle. Again no chipping, flat spots or dulling of the edge.
4. Batoned the blade through the antler. Now I got a big old wave in the edge. The edge again didn't chip, flatten or dull but did sustain permanent deformation. The waved section would still cleanly slice paper afterwards.
So now I'm thinking that I must have plenty fine grain for no chipping but contrary to the brass test perhaps the geometry is too thin. I wouldn't expect edge stability to be a problem at this thickness so maybe this "test" just goes too far. Again though I'm thinking that that a hotter temper may add some toughness.
Following that I figured I'd cut some cardboard and see what kind of edge retension I've got so I grabbed a box and cut it up into the smallest pieces I could make relatively quickly using only the section of blade from the wave forward. Cardboard is a fairly abrasive medium to cut so it usually accels at dulling an edge (usually)
To still be shaving sharp after that many cardboard cuts seems excellent performance to me which once again leads me to believe that a perhaps it could be a little softer for a better balance between edge retension and toughness
Satisfied with everything other than the wave on the edge I clamped the blade in the vise to break it. I've got the rough jaws on my vise and figured I'd just clamp it tight to break the blade which it did easily right at the vise jaws. Too easily, but now I'm not sure if it broke easily because of hardness or because I clamped it tight with sharp vice jaws instead of using smooth jaws. Thought I'd add that PVC is NOT a good leverage handle as the tang blew right through the back side when the blade snapped. Guess I'll get a piece of pipe for next time.
Now looking at the grain it appears to be pretty fine but I've seen better so I'm thinking i'll normalize 2 more times at 1425 to attempt to maximize grain refinement. The break does look fairly rough (especially toward the spine) like it tore apart as opposed to snapping clean. I'm honestly not sure what to think about that. A product of grain being bigger than what it could be ? Perhaps a sign of a problem in the grain boundries ? Or just a product of tempered steel that wants to stay together until it's literally torn apart ?
A couple of my buddies do have Rockwell testers so eventually I'll get this blade tested which will assist in determining the tempering temp needed. But in attempting to figure this out without a tester the method of tempering low and raising the temp till you get no chipping would lead me to believe I could temper at a LOWER temp and still be ok which is contrary to my suspision that the blade is still relativly hard.
As long as the edge will holds up I'd have no problem spring tempering the spine to add overall toughness to the blade.
Having recently got Parks 50 I'm working our my HT as it applies to Aldo's 1095 and want to achieve full confidence that I've got my HT nailed both as a challenge to my own abilities and a service to my customers.
This blade was created as a test blade but having been quenched 3 times (twice for hamon and finally fully hardened) it's not what will be my final recipe for this steel but I wanted to put it through some paces and see just what it would do then break to check grain structure.
I tempered at 400 2 hours x2
I finish ground the blade to .017 give or take .0005 then convexed the edge and sharpened on stones.
Throughout this testing I've realized that I'm not 100% confident in reading what the blade is telling me as it applies to HT.
I am very interested at this point of better testing methods with more meaningfull results so I'd LOVE to hear suggestions.
1. I tried "brass rod testing the edge on the corner of a brass bar but couldn't get the edge to deflect and the blade bit into the brass a bit. So now I'm thinking that the edge is still fairly hard at a 400 degree temper and perhaps thinner edge geometry would be better.
2. Whittled an chopped a little on a preasure treated 6x6. No damage or dulling
3. Chopped on an old dry antler as hard as you can chop with a 4" blade and no handle. Again no chipping, flat spots or dulling of the edge.
4. Batoned the blade through the antler. Now I got a big old wave in the edge. The edge again didn't chip, flatten or dull but did sustain permanent deformation. The waved section would still cleanly slice paper afterwards.
So now I'm thinking that I must have plenty fine grain for no chipping but contrary to the brass test perhaps the geometry is too thin. I wouldn't expect edge stability to be a problem at this thickness so maybe this "test" just goes too far. Again though I'm thinking that that a hotter temper may add some toughness.
Following that I figured I'd cut some cardboard and see what kind of edge retension I've got so I grabbed a box and cut it up into the smallest pieces I could make relatively quickly using only the section of blade from the wave forward. Cardboard is a fairly abrasive medium to cut so it usually accels at dulling an edge (usually)
To still be shaving sharp after that many cardboard cuts seems excellent performance to me which once again leads me to believe that a perhaps it could be a little softer for a better balance between edge retension and toughness
Satisfied with everything other than the wave on the edge I clamped the blade in the vise to break it. I've got the rough jaws on my vise and figured I'd just clamp it tight to break the blade which it did easily right at the vise jaws. Too easily, but now I'm not sure if it broke easily because of hardness or because I clamped it tight with sharp vice jaws instead of using smooth jaws. Thought I'd add that PVC is NOT a good leverage handle as the tang blew right through the back side when the blade snapped. Guess I'll get a piece of pipe for next time.
Now looking at the grain it appears to be pretty fine but I've seen better so I'm thinking i'll normalize 2 more times at 1425 to attempt to maximize grain refinement. The break does look fairly rough (especially toward the spine) like it tore apart as opposed to snapping clean. I'm honestly not sure what to think about that. A product of grain being bigger than what it could be ? Perhaps a sign of a problem in the grain boundries ? Or just a product of tempered steel that wants to stay together until it's literally torn apart ?
A couple of my buddies do have Rockwell testers so eventually I'll get this blade tested which will assist in determining the tempering temp needed. But in attempting to figure this out without a tester the method of tempering low and raising the temp till you get no chipping would lead me to believe I could temper at a LOWER temp and still be ok which is contrary to my suspision that the blade is still relativly hard.
As long as the edge will holds up I'd have no problem spring tempering the spine to add overall toughness to the blade.