Fellow knifemakers,
As per my commitment to share my test results Im doing so in this post. Please note, I'm not interested in any personalities, egos, irrational discussions or fanciful interpretations of what I am saying. You wont get any responses from me on those sorts of comments.
FULL DISCLOSURE: I do not make any money from my knives - in fact it costs me money. Its a hobby I find therapeutic and fun. I have no commercial interest in knives or related services. I am an engineering consultant where I an run an independent services business to industry. I was initially looking at a 3 week wait for the shop to do the processing. I have a client who uses the shop with big dollar orders and was able to leverage priority for all my orders at normal prices. The shop did not know there was any testing to be done, it was simply a routine order for them processing "parts". I consider myself to be an honest and ethical man, and I certify everything in this report is true and correct to the best of my knowledge.
FACTS IN DEEP CYRO TREATMENT:
Scientific research has shown in some materials a:
* Conversion of retained austentite to martensite
* Enhanced precipitation of small carbides
* Small increase in hardness
* Deep cyro provides more benefit that cyro processing
POINTS NOT FULLY SETTLED
* There is examples of something else happening with deep cyro as non steel materials are also showing some benefits as discovered in research papers by NASA.
* There has been examples that toughness may be negatively effected.
* There is examples of tool steel being easier to work post treatment
* There is examples of completed parts post tempering have greater service life
CLAIMS MADE
* Mike Stewart claims a 200 - 400 % better edge taking and edge holding.
* Busse claims a benefit but wont detail further due to his proprietary process.
* Research papers and various industry evidence have found a 420% increase in wear resistance of 52100 industrial tooling. Please note, these are not knives that we use.
PROCESS
I get my 52100 from a client/colleague who has a 100 ton press. He receives new annealed 52100 and works it into suitable blanks for me. I do stock removal, and I tend to do full flat ground drop point knives. The further processing is done at the processing shop. There it is hardened / quenched in a computer controlled industrial oven using one cycle. Of the four samples, one was not cyroed, the other three were. Immediately following quenching the profile was a slow draw down to -310F, held for 24 hours, then a slow rise until triple quenching. I do not profess this process is optimal, its simply what I had available to me.
TESTS
I was looking at CATRA tests, ASTM tests and other types and pondering how I might build a test harness to test it with. Looking at other tests conducted in the past it had received criticism that substantially different results are obtained in human hands. In the end I decided to get my son who as delighted to participate in the tests to cut nylon rope. A small wooden jig was put together to feed the rope and provide a backstop against the nylon rope. I figure that a real test with a human would best give me meaningful human performance indicators. As far as possible I instructed and observed my son perform the same type of cuts at the same angle, within reasonable human error. The blades were marked with roman numerals where only my wife knew what knives were what during the test. The cuts were stopped at the point which my son was unable to cut the rope using his fingers in the standard testing position he was using.
RESULTS
* There was no standard deviation of the blades beyond what could reasonably considered within the realm of human error in the testing.
* The deep cyro blades exhibit a 23% better edge retention. I mean that it was able to cut 23% more rope by my son in this test position on the jig.
* My results do not correlate to Mike Stewart's 200 - 400 % better edge retention. I do not know Mike Stewart's material or his process and am therefore unable to offer a fair and reasonable comment as to why the difference exists.
* An observation, not something I'm willing to state as fact right now, was that sharpening the cyro blades up afterwards seemed to me to be noticeably easier.
* I have a colleague/friend who is a metrologist and I have given the samples to him to have a look at. I hope to get some interesting metrics back from him. In particular I am interested in metrics about hardness and toughness from him.
* This is not the end of my tests its simply the beginning. Maybe it is possible to get 200% - I don't know. What I do know is there lots more inquiry to do.
I welcome people to repeat the test or do different ones, thanks.
Best Wishes.
As per my commitment to share my test results Im doing so in this post. Please note, I'm not interested in any personalities, egos, irrational discussions or fanciful interpretations of what I am saying. You wont get any responses from me on those sorts of comments.
FULL DISCLOSURE: I do not make any money from my knives - in fact it costs me money. Its a hobby I find therapeutic and fun. I have no commercial interest in knives or related services. I am an engineering consultant where I an run an independent services business to industry. I was initially looking at a 3 week wait for the shop to do the processing. I have a client who uses the shop with big dollar orders and was able to leverage priority for all my orders at normal prices. The shop did not know there was any testing to be done, it was simply a routine order for them processing "parts". I consider myself to be an honest and ethical man, and I certify everything in this report is true and correct to the best of my knowledge.
FACTS IN DEEP CYRO TREATMENT:
Scientific research has shown in some materials a:
* Conversion of retained austentite to martensite
* Enhanced precipitation of small carbides
* Small increase in hardness
* Deep cyro provides more benefit that cyro processing
POINTS NOT FULLY SETTLED
* There is examples of something else happening with deep cyro as non steel materials are also showing some benefits as discovered in research papers by NASA.
* There has been examples that toughness may be negatively effected.
* There is examples of tool steel being easier to work post treatment
* There is examples of completed parts post tempering have greater service life
CLAIMS MADE
* Mike Stewart claims a 200 - 400 % better edge taking and edge holding.
* Busse claims a benefit but wont detail further due to his proprietary process.
* Research papers and various industry evidence have found a 420% increase in wear resistance of 52100 industrial tooling. Please note, these are not knives that we use.
PROCESS
I get my 52100 from a client/colleague who has a 100 ton press. He receives new annealed 52100 and works it into suitable blanks for me. I do stock removal, and I tend to do full flat ground drop point knives. The further processing is done at the processing shop. There it is hardened / quenched in a computer controlled industrial oven using one cycle. Of the four samples, one was not cyroed, the other three were. Immediately following quenching the profile was a slow draw down to -310F, held for 24 hours, then a slow rise until triple quenching. I do not profess this process is optimal, its simply what I had available to me.
TESTS
I was looking at CATRA tests, ASTM tests and other types and pondering how I might build a test harness to test it with. Looking at other tests conducted in the past it had received criticism that substantially different results are obtained in human hands. In the end I decided to get my son who as delighted to participate in the tests to cut nylon rope. A small wooden jig was put together to feed the rope and provide a backstop against the nylon rope. I figure that a real test with a human would best give me meaningful human performance indicators. As far as possible I instructed and observed my son perform the same type of cuts at the same angle, within reasonable human error. The blades were marked with roman numerals where only my wife knew what knives were what during the test. The cuts were stopped at the point which my son was unable to cut the rope using his fingers in the standard testing position he was using.
RESULTS
* There was no standard deviation of the blades beyond what could reasonably considered within the realm of human error in the testing.
* The deep cyro blades exhibit a 23% better edge retention. I mean that it was able to cut 23% more rope by my son in this test position on the jig.
* My results do not correlate to Mike Stewart's 200 - 400 % better edge retention. I do not know Mike Stewart's material or his process and am therefore unable to offer a fair and reasonable comment as to why the difference exists.
* An observation, not something I'm willing to state as fact right now, was that sharpening the cyro blades up afterwards seemed to me to be noticeably easier.
* I have a colleague/friend who is a metrologist and I have given the samples to him to have a look at. I hope to get some interesting metrics back from him. In particular I am interested in metrics about hardness and toughness from him.
* This is not the end of my tests its simply the beginning. Maybe it is possible to get 200% - I don't know. What I do know is there lots more inquiry to do.
I welcome people to repeat the test or do different ones, thanks.
Best Wishes.
