Category: Edge Retention

4 thoughts on “Edge Retention”

  2. Way slow in the reply here, but it has a large carbide volume and can hold high hardness. So, it’s not going to end up that tough, but it will be strong.

    I did a plane iron test (for woodworking) two years ago and found it to plane double the linear footage that O1 will at same hardness.

    Then larrin posted his results confirming that was in line with catra testing (which was a relief – I got a lot of grief from the woodworking community). What I’ve found since then is that you have to have something relatively easy on the edge (so planing rough lumber will reduce its advantage over more plain steels).

    But I’ve made a couple of mules out of XHP for the kitchen and it’s great for low toughness work (and where it won’t lay in salt and rust).

    Reply

  3. I’m just curious looking at the large steel comparisons, I don’t quite understand, I’ve been told that high carbon steel holds an edge very well but all the high carbon steels on your list seem to be very poor at edge retention. I am just a very uneducated person on this topic who just happened upon this looking for interesting comparisons between knife steels so if I’m missing something or glossing over something on accident I apologize I am just very confused honestly.

    Reply

    1. Low alloy and simple carbon steels have a small volume of low hardness carbide called cementite. That means the west resistance is much lower than high alloy steels that have more carbide and the carbide is higher in hardness. This is discussed in the CATRA articles and Knife Engineering.

      Reply

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Edge Retention, History - Articles - Books, Steel and Knife Properties

S90V and S125V Knife Steel – History, Properties, and How to Heat Treat

Larrin

Thanks to Gabe Newell, George Thorpe, Jason, Rogelio Escobedo, Wes Newman, and Wayne Sears for becoming Knife Steel Nerds Patreon supporters! On Patreon there is a new article exclusive to supporters about Artisan Cutlery’s exclusive steel AR-RPM9. The composition was recently announced so I analyzed the composition. read more

Edge Retention

CATRA Tests of M390 Knives

Larrin

Thanks to Yuval Peleg, Patrck Roehrman, Hugo Costa, and Stefan Stromberg for becoming Knife Steel Nerds Patreon supporters!

CATRA Testing of M390 Knives

Recently two sets of CATRA studies of M390 knives have been reported. One was conducted by Mike Latham of CollectorKnives, and the other by a group of people including Clint of the Alchemy_1 Youtube channel. These reports are the product of a minor controversy over the Rockwell hardness of production knives and the relation between Rockwell hardness and edge retention. Here are links to both reports: read more

Corrosion Resistance, Edge Retention, Edge Stability, Steel and Knife Properties, Toughness

How to Design Knives that Do Not Fail

Larrin

Thanks to Tom Krein, Joshua Goldstein, Matthew Maola, Edo Vernoschi, Nils Anderssen, and Cedric & Ada for becoming Knife Steel Nerds Patreon supporters!

Failure Modes

A common engineering technique is to evaluate designs based on how they failed, or may fail. Failure modes are identified and the designs are modified to prevent those failures. These ideas are simple in concept but it is surprising how easy it can be to miss the forest for the trees. In terms of predicting failure modes in some cases it is easy and in some it is difficult. You would expect a large chopping knife to require heavier edge geometry to prevent chipping and rolling, or a seawater diving knife to require high rust resistance. Other times failure modes are identified through testing of the knife or by returns from customers. Whatever the source of the failure, there are usually relatively simple methods for fixing each one, though the trade-offs for doing so may not be desirable. read more

Austenitizing, Edge Retention, History - Articles - Books, Steels, Tempering, Toughness

A2 Steel – History and Properties

Larrin

Thanks to Dan Pierson, Steve R. Godfrey, Bryan Fry, and Timothy Becker for becoming Knife Steel Nerds Patreon supporters!

History

A2 steel is quite old, though determining the exact year it was released is a bit difficult. A2 steel was developed in the early 20th century during the explosion of tool steels that occurred after the discovery of high speed steel which was first presented in 1900. You can read about that history in this article: The History of the First Tool Steel. During the development of the first high speed steel included the switch from manganese to chromium as the primary hardenability element, and most high speed steels had about 4% Cr. That high chromium content was primarily for “hardenability” which is the degree of cooling required to achieve full hardness. A “water quenching” steel has low hardenability and must be quenched very rapidly from high temperature, and an “air hardening” steel can be left in air and it will fully harden. You can read more about hardenability in this article on quenching. The first high speed steel came to be known as T1, which had 4% Cr and 18% W (tungsten). The earliest record I have found of a precursor A2-type steel is in a summary of tool steels in 1925 [1], while summaries of tool steels from 1910 [2] and 1915 [3] do not have any similar steels. Therefore these types of steels probably arose sometime between 1915 and 1925. read more

Edge Retention, Steel and Knife Properties

Can CATRA predict Rope Cutting Performance?

Larrin

Thanks to Fingal Ferguson for becoming a Knife Steel Nerds Patreon supporter!

CATRA Edge Retention Testing

I previously wrote articles about CATRA testing of edges. The CATRA test uses 5% silica-impregnated cardstock which it slices with a fixed stroke length and force. The first article primarily looked at the effect of edge angle on edge retention; specifically, that edge angle greatly controls edge retention: read more