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Knives, Erik Coccia, Francisco J. Which Steel Has the best Edge Retention? They line up relatively well with each other. While consulting for a knife manufacturer, I learned that they had recently replaced their CATRA edge retention tester because the old one had given them some problems.

My wife was not happy when she learned how much money I gave up to instead take an old edge retention tester which may or may not work correctly. And that was before she learned how much space it would take up in the garage. When I learned I would be getting the edge retention tester, I took just about every knife steel that I had and started heat treating a set of blanks for testing.

That was just before Christmas. I then got the tester in mid-January and my excitement was tempered amazing heat treating pun marking knife comparison analysis bit. Several parts of the machine were damaged in shipping and I was not sure if I would be able to get it working again. Among the parts of the machine I had to fix included:. So fixing all of that took me about 45 days and a lot of yelling and swearing.

The machine is surprisingly complicated but at the same time it performs a relatively simple task. In other words, it records how much marking knife comparison analysis is cut with each stroke. The tester is pneumatic and the series of tubes and circuit boards used to operate marking knife comparison analysis machine can be somewhat daunting at first, but again, most of what it is doing is lowering and raising a head with clamped cardstock and moving a knife back and forth.

Technically any media of an appropriate size could be put in rather than the standard silica-impregnated paper but thus far I have only used the paper. On the other hand, some components of the machine marking knife comparison analysis simpler than I would have thought.

The 50 Newton force is maintained by a big steel cylinder on top of the head of the machine. Also the paper comes loose as 10mm wide strips, and Marking Knife Comparison 90 they must be stacked together by hand and inserted into the machine which is somewhat tedious.

A knife edge retention tester in itself is not necessarily useful without a good set of experiments to perform on it. There have been other attempts at comparing the edge retention of different steels in the past. And rope cutting experiments have been done by many people. There were several things I wanted to do to marking knife comparison analysis the best test results I can. One is using a consistent knife design to eliminate the effects of different edge geometries and knife designs.

For example, many of those reporting edge retention experiments are limited to what knives are commercially available which means they marking knife comparison analysis little control over heat treatment and edge geometry. Using different edge geometries in particular makes comparisons about steel or heat treatment almost impossible.

For example, here is the difference in measured edge retention for CM with different edge angles:. The edge angle can be relatively easy to change with sharpening. And different knife companies will heat treat steels to different hardness levels using different heat treatment parameters such as some using cryogenic processing and others marking knife comparison analysis. So I decided to make a simple test knife design which utilizes a rectangular shape marking knife comparison analysis edge so curves do not affect cutting with a consistent primary bevel and edge thickness.

Keeping the primary bevel the same means that steel of different thickness can be used, only the height of the primary bevel changes based on the stock thickness. The test uses a 40mm cutting distance, so the 2. After I heat treated and surface ground all of the blanks, I shipped them to knifemaker Shawn Houston of Triple B Handmade Big Brown Bear who ground the bevels and put the initial edge on the knives.

To maintain precise angles, an Edge Pro was used and the resulting angle was checked with a laser goniometer. Using bonded CBN rather than abrasive on a plate makes it cut more like a traditional stone whereas diamond and CBN plates tend to leave deeper scratches [1]. However, the previously linked CM article found a peak in edge retention with a grit diamond plate, with reduced edge retention using a lower grit or higher grits like or This was somewhat puzzling and perhaps was due to the relatively poor sharpness that marking knife comparison analysis result from very coarse diamond plates like theor deburring challenges from such a coarse stone.

I tested the effect marking knife comparison analysis the degree of polish with tests of an AEB-L knife with a grit metallic bonded CBN, the grit we ended up using, and then polished up through 0. The marking knife comparison analysis retention was reduced with higher levels of polish. I plotted vs micron marking knife comparison analysis than grit because of the many different grit systems which leads marking knife comparison analysis more confusion than anything.

So a grit stone was chosen to use a finish which is more optimized for slicing without going crazy with something very coarse like grit which is somewhat unlikely to Marking Knife Comparison Rate be used by most knife owners. Unlike when slicing, with push cutting, a higher polish is superior because of the higher potential sharpness and the reduced resistance when marking knife comparison analysis the knife through the material.

The use of very marking knife comparison analysis CBN cubic boron nitride helps when sharpening steels with high hardness carbides like vanadium carbide which are harder than aluminum oxide, the most common abrasive used in sharpening stones. The resulting sharpness was checked with the Edge on Up tester to ensure the knife was measured as no higher than g with the BESS media.

This test is not perfect for our purposes since we are testing edge retention with a slice but the sharpness is measured with a push cut. However, the BESS tester helped with ensuring the sharpness was relatively consistent marking knife comparison analysis knives and across an edge of an individual knife.

Also, when burrs were present this generally resulted in reduced sharpness on the tester, and those burrs were not always noticed when feeling the edge or slicing paper. When one of the tests looked substantially different than the other two I performed a fourth test as a tiebreaker. In general the results between re-tests were pretty consistent but there were cases when an individual test would be worse than the others.

Surprisingly, I could tell little difference between the knives in terms of setting the edge when resharpening. The CATRA test results in extremely dull edges, you can run your finger along the edges marking knife comparison analysis no fear of being cut.

However, a burr was raised on each side with a similar number of passes regardless of the knife, even when comparing the ultra wear resistant Rex to a low wear resistance steel like Perhaps this was due to the relatively coarse sharpening stone of marking knife comparison analysis or the very hard CBN abrasive.

I marking knife comparison analysis differences between steels would be more apparent if sharpening out marking knife comparison analysis chip, re-profiling to a different edge angle, or polishing to high finishes. The biggest differences in ease in sharpening were instead with burr removal.

The only truly difficult to sharpen knife was in RexI believe this was the result of high retained austenite rather than pure wear resistance, as Rex 86 and 15V sharpened fine. Some steels which were also expected to have relatively high retained austenite like Vanax also were relatively difficult to deburr. A modified heat treatment for reduced retained austenite would be expected to lead to greater ease in sharpening, though sharpening to higher polish where the burr size is reduced would also help.

Below shows a chart summarizing all of the steels marking knife comparison analysis heat treatments which were utilized, along with the measured edge retention on the CATRA tester in mm. All of the steels were given a cryo treatment after quenching except for one D2 knife which was made to compare the effect of cryo.

I was targeting Rc for most of the knives apart from a few that are basically never used at that hardness, such as ZDP, Rex 86, Rex1. Because my experience with heat treating each steel varies, and there is always some variation in hardness, the resulting hardness for most steels was between 60 and 63 Rc.

See the following marking knife comparison analysis with temperatures in Celsius instead here. And for an easier view of the relative edge retention of each steel Marking knife comparison analysis have a chart below.

For the steels which were tested at multiple hardness levels I have dots connected by lines. The chart also has dotted lines which represent the expected effect of hardness higher hardness means better slicing edge retention marking knife comparison analysis, so that steels can be marking knife comparison analysis at different hardness levels. This value came from a previous article where an average difference of Marking Knife Comparison 10 Some steels deviated from that expected hardness contribution a bit which will be discussed in the effect of heat treatment section.

Rex 86 is the same as Z-Max. AEB-L is the same as 13C CD 1 is the same as Z-Tuff. ZDP and Cowry-X are very similar. In previous articles I generated this regression equation based on the contribution of edge angle, steel hardness, and volume of each carbide type. I also included tables with carbide contents of a range of different steels in Part 1 and Part 2.

Here is the result of marking knife comparison analysis prediction equation vs what was measured in this study:. The trend is very good, with the biggest deviations being Z-Max high and Blue Super and 1. I will address these along with other small deviations below. As I explained in the previous CATRA articles, the performance of each steel marking knife comparison analysis highly dependent on marking knife comparison analysis amount volume and hardness of the carbides.

Here is a summary chart of different carbide types:. Measuring the hardness of carbides is difficult experimentally and some sources vary. For example, I have seen some papers report a hardness of Hv for M 6 C rather thanwhich might be a better result as I will discuss below.

In general, steels with higher vanadium did better, as expected. Vanadium carbide is very hard so it contributes to wear resistance and edge retention very strongly. These values are normalized to 61 Rc by using the The above is marking knife comparison analysis a range of vanadium-alloyed steels including stainless and non-stainless tool steels. It is somewhat surprising that they end up trending so well vs vanadium content because the overall carbide content in each steel can be pretty different.

This is significant for toughness as is discussed in the toughness-edge retention balance section. For low-alloy steels at the bottom of the chart, they have cementite iron carbide rather than chromium or vanadium carbides.

In that case there was no trend with increasing carbide content. If anything it was slightly negative:. It is more likely that the negative trend is random within the variation inherent in the test.

Many sources show silica as being higher in hardness than cementite [5]. It could be that with the cementite being softer than silica that the cementite is not improving edge retention. With a different test media it may be that more differentiation would be found between the cementite-containing steels.

Currently most of the low-alloy steels seem to be affected only by the bulk hardness of the steel rather than carbide content. This would be my guess as to why O1 tested a bit lower than ; the two steels probably perform similarly but due to experimental variability or some small unknown factors marking knife comparison analysis O1 slightly underperformed.

Another point in favor of the hypothesis that cementite is softer than silica is the fact that performed a bit better than most of the other low alloy steels. The 1. Perhaps it was enough to make the cementite harder than the silica in the paper.

Instant downloads of all LitChart PDFs (including The Birthmark). LitCharts Teacher Editions. Teach your students to analyze literature like LitCharts does. Detailed explanations, analysis, and citation info for every important quote on LitCharts. The original text plus a side-by-side modern. Chapter II A Brief History of TPA. Dr. Alina Surmacka Szczesniak, a food scientist, principal at General Foods, and a founding editor of Journal of Texture Studies, developed the original TPA parameters as part of the sensory work she conducted in the early 's at General Foods' Technical www.- Szczesniak's extensive early publications focused on understanding the textural attributes. So the knife becomes a less than quality item, as features, materials, and workmanship are whittled away in the name of cost-based analysis. In this trade, I call this bean counter process lowballing. This means cutting labor and expenses while hyping styles, vague aspects of materials, or using heavy advertising promotions to push a product.

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