06-13-2018, 02:24 PM
Here's a little sneak peek at our testing with one of the twelve A2 heat treated samples.
We were very interested in a couple of things that we can quickly and easily test for; (1) Can we, in fact, sharpen edges, then send them to heat treat and expect to receive back still-sharp edges and (2) do these pre-sharpened, post heat treated edges, roll?
If the initial results reported below hold up through the balance of the testing, then we are well on our way to answering both of these questions .
We picked our #6 sample that was ground with a double bevel and then sharpened and deburred to BESS 340 and that number represents an average sharpness level across the edge. It was very difficult to obtain a consistent sharpness level across the edge working with unhardened steel. #6 was hardened to HRC50. Out of the box it measured 760. It was obvious that the steel was covered in heat treat residue and hand stropping on plain leather began to remove the residue. We stopped stropping/cleaning at 420 because that was good enough for this intended short test. It was obvious to us that edges can be pre- sharpened before heat treat without disastrous consequences. We could have applied our Kally's leather belt to the cleanup process but we didn't want to introduce any power elements to this particular test. Later we will see if the original sharpness level can be returned to this edge without the use of abrasives.
We know, from previous Stage I (one cycle) tests, that edges sharpened to 400 roll. Not nearly as much as 150 edges but they still roll. The question was, will this 420, pre-sharpened and post heat treated, edge roll as well? The answer is yes, it did. To be honest, we all predicted, here at EOU, that it wouldn't...but it did. After a Phase I test (five back and forths over the edge (one cycle)) the edge sharpness was reduced to 480. After four additional cycles it rolled to 590. This is all very much in line with what we have witnessed in previous tests with edges sharpened to the 400 level. But... did it roll or did the apex just crumble as a result of the lateral force applied to it? We have two good tests that answer that question. (1) Edges that have rolled 170 points often can be detected (felt) with a fingernail. This roll was easily detected with a fingernail on the rolled section of #6's edge. (2) Edges that have rolled less than 300 points can usually be stropped straight again and returned to at or very near their pre-roll sharpness levels. After edge straightening, our 590 edge then measured 380 or forty points better than where we began the test. We attributed (best guess) the improvement to simply more removal of gunk on the edge. We anticipate that further stropping would likely return the edge, at least, to it's pre-heat treat level and we'll let you know later where it did finally end up.
So we have, what we think, are some pretty telling initial results that very well might have ramifications upon other areas of the sharpening debate. We have plenty more edges to test and we'll see if these initial results hold across the board. We also have other factors to test for including the original goal of these tests, how rolling of sharpened edges is affected by HRC level. Curiosity got the best of us with this first short test. From here on out we'll have to get a little better organized.
We were very interested in a couple of things that we can quickly and easily test for; (1) Can we, in fact, sharpen edges, then send them to heat treat and expect to receive back still-sharp edges and (2) do these pre-sharpened, post heat treated edges, roll?
If the initial results reported below hold up through the balance of the testing, then we are well on our way to answering both of these questions .
We picked our #6 sample that was ground with a double bevel and then sharpened and deburred to BESS 340 and that number represents an average sharpness level across the edge. It was very difficult to obtain a consistent sharpness level across the edge working with unhardened steel. #6 was hardened to HRC50. Out of the box it measured 760. It was obvious that the steel was covered in heat treat residue and hand stropping on plain leather began to remove the residue. We stopped stropping/cleaning at 420 because that was good enough for this intended short test. It was obvious to us that edges can be pre- sharpened before heat treat without disastrous consequences. We could have applied our Kally's leather belt to the cleanup process but we didn't want to introduce any power elements to this particular test. Later we will see if the original sharpness level can be returned to this edge without the use of abrasives.
We know, from previous Stage I (one cycle) tests, that edges sharpened to 400 roll. Not nearly as much as 150 edges but they still roll. The question was, will this 420, pre-sharpened and post heat treated, edge roll as well? The answer is yes, it did. To be honest, we all predicted, here at EOU, that it wouldn't...but it did. After a Phase I test (five back and forths over the edge (one cycle)) the edge sharpness was reduced to 480. After four additional cycles it rolled to 590. This is all very much in line with what we have witnessed in previous tests with edges sharpened to the 400 level. But... did it roll or did the apex just crumble as a result of the lateral force applied to it? We have two good tests that answer that question. (1) Edges that have rolled 170 points often can be detected (felt) with a fingernail. This roll was easily detected with a fingernail on the rolled section of #6's edge. (2) Edges that have rolled less than 300 points can usually be stropped straight again and returned to at or very near their pre-roll sharpness levels. After edge straightening, our 590 edge then measured 380 or forty points better than where we began the test. We attributed (best guess) the improvement to simply more removal of gunk on the edge. We anticipate that further stropping would likely return the edge, at least, to it's pre-heat treat level and we'll let you know later where it did finally end up.
So we have, what we think, are some pretty telling initial results that very well might have ramifications upon other areas of the sharpening debate. We have plenty more edges to test and we'll see if these initial results hold across the board. We also have other factors to test for including the original goal of these tests, how rolling of sharpened edges is affected by HRC level. Curiosity got the best of us with this first short test. From here on out we'll have to get a little better organized.