Recent content by Kevin R. Cashen

  1. Kevin R. Cashen

    Another fun heat treatment topic this week.

    Here is another one, that I thought was worth sharing. It is fun, because it is easy when you understand the process but may seem mysterious for many. One of the weekly phone calls, or e-mail, that I received this week had a good question. I will paraphrase it something like this- “Kevin, I...
  2. Kevin R. Cashen

    Heat treatment or geometry, which is more important?

    Get your cup of coffee, this will take a bit. ;) I have been working on article and video ideas and wanted to see if this one could be of interest. When I began learning about the fascinating effects of heat treatments on the properties of steel, I fell into the mindset that the three most...
  3. Kevin R. Cashen

    Heat treating 52100 and 80crv2

    With the level of V and Cr present, the extra C doesn't really apply, as it will be locked up in carbide.
  4. Kevin R. Cashen

    When am I a “knife maker”?

    A topic that is mostly opinion reliant, but what the heck I have two pennies in my pocket as well. I think anybody who has dedicated themselves to the craft, in order to make sure that every blade they make has to be better than the last, even if it costs them money at times, can call...
  5. Kevin R. Cashen

    Wilson Hardness Tester

    Hold on! I just looked at your picture again and noticed the toggle switch and electrical cord on that unit. These normally don't have anything electrical, so I would guess that this is one of the delux models with and automatic unloader, if so I would be all over that thing! The average...
  6. Kevin R. Cashen

    Wilson Hardness Tester

    I just refurbished a 4JR unit and, while it is heavy, it is not that heavy; a young man, with a good back, could heft it into your car. The weight quoted by BRYSTAR no doubt includes the crating, packaging and accessories. That being said- don't move it with the weights on the unit. The 1JR...
  7. Kevin R. Cashen

    Will Ferric acid solution take away carbon?

    The carbon, iron and acid confusion had me reread things a couple of times as well Ed. Don’t worry Mark, these are all very understandable confusions, that I myself would have had when I was getting started with them. I thought I would add a note here because I have a lot of hours logged with a...
  8. Kevin R. Cashen

    Heat treating 52100 and 80crv2

    The NJSB hardening numbers are good but I do not understand the normalizing recommendations. 1650°F yes, that is what I recommended to them years ago, the 1500°F isn't too bad but you can also drop right down to 1475°F without it and save some time. The one I don't like is the 1350°F, it falls...
  9. Kevin R. Cashen

    Heat treating 52100 and 80crv2

    I cringe everytime I read those far too high numbers. The only reason to go this high is if the steel is carbon locked through extensive annealing, and that is why I recommended the normalization to NJSB... yeah that was me. When Aldo originally got the business going, my phone would often...
  10. Kevin R. Cashen

    Tempering equipment question

    Never place blades flat, on their sides, on any surface, during a heat treatment operation. Unless you are shooting for warped blades. The less material you have touching that blade during tempering, the better. When I have taught classes that had small ovens that required blades to overlap...
  11. Kevin R. Cashen

    zig zag pattern?

    A lot will depend on what you do to test the edge. I am not a fan of the brass rod test, as it actually doesn't even tell people anything about what they think it does. What a heavily banded edge will do is sharpen, and wear, differentially giving it a micro-serrated effect. This will make it...
  12. Kevin R. Cashen

    zig zag pattern?

    It would come down to how one defines "homogenous", as technically none of the phases, aside from very high temp austenite, is homogenous. When casually observed under the microscope martensite looks like a very uniform structure, but on higher magnification one sees the individual lathe...
  13. Kevin R. Cashen

    Harden Tiny Knife

    There is a rather big difference between 1095 and O-1. 1095 will be the easiest to HT as an after thought.
  14. Kevin R. Cashen

    Quenching oil question

    A great primer that I often recommend, and have used it as a textbook in classes that I have taught, is "Metallurgy Fundamentals" by Daniel Brandt. This book is about high school level in explaining things, and once read you will be able to move onto about any average metallurgy text. After...
  15. Kevin R. Cashen

    Quenching oil question

    Properly maintained, those oils can last you for years, for the advantages in producing quality blades and the shortest learning curve, it is one of the biggest bangs for your buck you can get as a knifemaker. There has been a lot of resistance over the years to this advice, but not a single...