Different batches of steel means different cutting ability
I have adopted an alternative set of standards for cut-testing in 1/2-inch manila or sisal rope that doesn’t require as much work for the tester. Instead of using
1-inch of blade to cut with until I am sawing at the rope ineffectively, as I have done in the past, I am now only counting the number of single-slice cuts I can accomplish. Ten to 20 single slices before having to make a second push to completely sever the rope rates as a serviceable knife. Forty to 80 single slices rates as a knife with good cutting endurance. One hundred to 200 slices rates as excellent. Two-hundred fifty to 500 rates as superior. Six hundred to 900 rates as extraordinary. Over 1,000 single slices is phenomenal.
I came up with this adjusted procedure to make it easier to measure the same relative results I had been getting without having to work so hard to accomplish the test. Results are still reproducible with the same knives within plus or minus 5 percent.
Only the top-performing 30 percent of all knives made will manage to rate having excellent cutting endurance or better. Of that 30 percent, two thirds of the knives will be excellent, and slightly less than one third will be superior. The top 1 or 2 percent will be extraordinary. Knives that are spectacularly phenomenal are so rare, they might only be encountered by accident and amount to a fraction of a percent of all knives made.
Knives that are the easiest to sharpen probably won’t rank excellent or better for cutting endurance. The knives that achieve the greatest cutting endurance will invariably require a little more effort to sharpen if you cut with them until they dull. Using my modified cut testing procedure allows all knives to be restored to hair-shaving sharpness with only a modest amount of effort. It would seem that keeping a knife sharp by regular edge maintenance is easier to accomplish than restoring sharpness to a thoroughly dull edge. There will never be consensus agreement about what balance of cutting endurance and re-sharpening characteristics are best for all knife makers to work at providing.
It appears that most generalizations regarding the performance of specific steel alloys fall far short of being predictably accurate. The 1095 alloy used in this vintage Marbles test knife is a good example of the extreme range of variability one can encounter with the same steel alloy. With a percentile alloy content of 0.9 to 1.0 percent carbon and 0.3 to 0.5 percent manganese, this simple carbon steel has been used to make knives with Rockwell hardness ratings that run from the high 40s to the low 60s.
Knives I have tested with 1095 steel blades cross the entire spectrum of cutting endurance performance from barely serviceable to spectacularly phenomenal. Many knifemakers and pundits attribute these variations to differences in heat treatments and edge geometries. Certainly this accounts for many of the variations. But I suspect that the particular batch of steel being used plays a big part also. It is easier to make a good performing knife with a good batch of steel. Using a batch of steel that is not especially suited to cutlery applications, even with the best knifemaking techniques and procedures applied in the most conscientious way, may only produce a knife with average cutting endurance.
A knife might take a keen edge and be easy to sharpen, but only knives made with a production batch of steel that has the greatest potential for cutlery applications will attain superior or greater cutting endurance performance. Neither steel makers nor knife producers are willing to admit that they may not be totally in control of the finished quality of their product as it relates to the knife’s cutting endurance.
At this time, I do not believe there is any way of predicting what the cutting endurance potential of an individual production lot of steel will be. Only the finished knives will demonstrate what the cutting endurance potential is after receiving the best heat-treatment procedures and optimum edge geometry for the blade. Identical knives from the same producers that have the same heat treatments and edge geometries may vary in cutting endurance performance depending on the production lot of steel used.
Because there are no industry-accepted standardized-test procedures that can be reproduced by cutlery consumers to compare results of finished blades with each other, most knife users are not really aware of how much performance variation exists between knives that are visually identical but made at different times using the same techniques, by the same knife producers.
What started out as a project to document what steels cut the longest between sharpening, turned into a realization that knives made of the same steels by the same makers to the same standards weren’t predictable. The one thing most impressive about this is how many knife users rationalize the results they experience with the knives that are theirs into being what they decide is the best possible result they could own. It may be that selecting a knife for individual use is always going to be as subjective as selecting a life partner.
A representative of a major U.S.-based knife specialty company told me that he was sure his company used the very best knife steels because they bought the most expensive steels to use. When I told this factory rep about 10-fold variations in rope cut testing results that I had experienced with one of the steels used by his knife brand he dismissed the validity of my test because the sample size was too limited. Then he proceeded to recount how his personal use of one of his company’s knives showed it to work very effectively at chopping green wood, while factory CATTRA tests of the same knife steel were “ho-hum.”
This exchange was typical of most conversations I have attempted with most successfully established knife producers about objective testing procedures. The knife producers tend to want consumers to believe they always produce the best possible knives. If there are exceptions, then those exceptions are only individual ones. Since I can’t test them all, I can’t refute that argument. I will suggest that when the knife in my hand won’t perform the same as another of the same make and model purchased at a different time, I have a good reason to not celebrate the knife producer’s assurances that I just happen to have won the booby prize.
I cut-test a lot more knives than the average knife aficionado will ever consider using, so I see things in use that most won’t. Ultimately, many knife producers resort to the response that if a knife doesn’t do what I expect, then I must be using it the wrong way. That response won’t be at all helpful in a combat or survival situation when someone’s life is at stake. Because of this, I will continue to push for the idea of standardized objective testing that end users can replicate for themselves as a way of proof-testing what a knife may be capable of before it lets anyone down.
By Michael S. Black