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Thin blade steel showdown!
- Thread starter TexasWade
- Start date
Excellent project, TW, thanks for doing this! The only suggestion that I would make is to make sure you do the testing that satisfies you. Trust me, you'll have no end of people second guessing your results and demanding you change this or that in order to get the results they want to see. That's one of the reasons I no longer release my results.
Formalize your process, and cut away! If anyone has a problem with it, they can independently duplicate what you are doing. My hat's off to you!
Formalize your process, and cut away! If anyone has a problem with it, they can independently duplicate what you are doing. My hat's off to you!
I appreciate that Sodak, and the plan is definitely to test as I please. However I also appreciate some input since I'm sure there are a ton of great ideas I haven't thought about.
So far here's what I'm thinking and as usual comments and criticisms are welcome.
First, off, I'm 90% certain I'm going to get the basic Wicked Edge sharpener. It seems like that's probably the road to the most consistent edges between all blades and resharpenings etc. With the diamond hones and relatively thin blades, sharpening should be reasonably quick. The finest hone included in the kit is 600g so that's what the tests will be based on. Also I'm thinking about doing all the cutting tests sharpened at 15dps and then repeating them at 20dps. The cutting tests I have in mind are as follows.
1) Paper slicing. Using a slick plastic cutting board, the blade will be mounted with the edge slightly embedded into the board. There will be a fence about 1/4" away from the blade and sheets of printer paper will be slid through repeatedly until I can no longer cleanly push the paper through the rig. Record total length of paper cut, repeat for all blades.
2) Carpet slicing. Similar test as #1 but with carpet, backing side up. I would like to do this with cardboard but I'm concerned that I may have to buy a lot of boxes by the time the cutting is done. I think the carpet will dull the blades quicker making for a quicker and less expensive test. Also if I start with a large piece of carpet I should have a more consistent test media than a stack of random boxes from the grocery store or whatever.
3) Lamp cord push cutting. The blade will be mounted to a lever so that downward motion will bring it into contact with the plastic cutting board. I will weight the end of the lever to put a specific load at the blades' point of contact at the board. The cord will be pushed along the fence in 1/4" increments and the blade will be gently lowered to cut the cord. I'll give it one free incomplete cut and at the second incomplete cut the number of cuts will be recorded. This will be instead of the classic rope cutting test but here I'm concerned that I could end up paying hundreds of dollars for enough rope to do my testing. The lamp cord is relatively cheap and should dull the blades faster than rope.
4) Staple drag. To simulate hitting a box staple while opening a package, I'll set up a rig (which I have not yet devised) to drag the blade across a box staple using a specific angle and pressure. Blades will be evaluated by looking at the edges with a microscope.
I think that will complete the cutting tests and I'll move on to more destructive testing.
5) Flex test. Mount the blade on a solid fixture and apply a specific amount of force (several pounds) and record the amount of flex. I would aim for what I feel is near the safe maximum without breaking anything.
6) Screwdriver test. I'm not sure exactly how I want to do it but I'm thinking maybe I could put a slot in a small socket end use a dial reading torque wrench while turning the socket on the blade edge. Record the torque applied and amount of flex at the first sign of chipping (or failure).
7) Tip impact. I'll make a dummy handle with tubular guide attached. The guide will slide along a rod and it will be oriented so I can drop the knife tip first at a shallow angle onto a granite tile. I will increase the drop height until some amount of the tip chips off. Would be cool to have a high speed camera for this one!
8) Corrosion. Mount the blades on an aluminum bar so I can hang them partly submerged in a salt water bath. Probably will also agitate the test setup daily so I get wet and dry cycles at the waterline. I may electrify the rig at a low voltage or add vinegar or other acid to speed up the test if needed.
So far here's what I'm thinking and as usual comments and criticisms are welcome.
First, off, I'm 90% certain I'm going to get the basic Wicked Edge sharpener. It seems like that's probably the road to the most consistent edges between all blades and resharpenings etc. With the diamond hones and relatively thin blades, sharpening should be reasonably quick. The finest hone included in the kit is 600g so that's what the tests will be based on. Also I'm thinking about doing all the cutting tests sharpened at 15dps and then repeating them at 20dps. The cutting tests I have in mind are as follows.
1) Paper slicing. Using a slick plastic cutting board, the blade will be mounted with the edge slightly embedded into the board. There will be a fence about 1/4" away from the blade and sheets of printer paper will be slid through repeatedly until I can no longer cleanly push the paper through the rig. Record total length of paper cut, repeat for all blades.
2) Carpet slicing. Similar test as #1 but with carpet, backing side up. I would like to do this with cardboard but I'm concerned that I may have to buy a lot of boxes by the time the cutting is done. I think the carpet will dull the blades quicker making for a quicker and less expensive test. Also if I start with a large piece of carpet I should have a more consistent test media than a stack of random boxes from the grocery store or whatever.
3) Lamp cord push cutting. The blade will be mounted to a lever so that downward motion will bring it into contact with the plastic cutting board. I will weight the end of the lever to put a specific load at the blades' point of contact at the board. The cord will be pushed along the fence in 1/4" increments and the blade will be gently lowered to cut the cord. I'll give it one free incomplete cut and at the second incomplete cut the number of cuts will be recorded. This will be instead of the classic rope cutting test but here I'm concerned that I could end up paying hundreds of dollars for enough rope to do my testing. The lamp cord is relatively cheap and should dull the blades faster than rope.
4) Staple drag. To simulate hitting a box staple while opening a package, I'll set up a rig (which I have not yet devised) to drag the blade across a box staple using a specific angle and pressure. Blades will be evaluated by looking at the edges with a microscope.
I think that will complete the cutting tests and I'll move on to more destructive testing.
5) Flex test. Mount the blade on a solid fixture and apply a specific amount of force (several pounds) and record the amount of flex. I would aim for what I feel is near the safe maximum without breaking anything.
6) Screwdriver test. I'm not sure exactly how I want to do it but I'm thinking maybe I could put a slot in a small socket end use a dial reading torque wrench while turning the socket on the blade edge. Record the torque applied and amount of flex at the first sign of chipping (or failure).
7) Tip impact. I'll make a dummy handle with tubular guide attached. The guide will slide along a rod and it will be oriented so I can drop the knife tip first at a shallow angle onto a granite tile. I will increase the drop height until some amount of the tip chips off. Would be cool to have a high speed camera for this one!
8) Corrosion. Mount the blades on an aluminum bar so I can hang them partly submerged in a salt water bath. Probably will also agitate the test setup daily so I get wet and dry cycles at the waterline. I may electrify the rig at a low voltage or add vinegar or other acid to speed up the test if needed.
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bodog
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I'd also suggest a caliper to measure the width of the shoulders as you sharpen and move to the next tests. Maybe you could borrow one of those knife sharpness testers from someone, too.
Number 6 sounds shaky at best. Every edge I've ever seen will get messed up pretty quickly doing what you're talking about (acting like you're using the knife as a screwdriver, I think). I'd suggest something more like getting a piece of hardened steel, clamping the knife in some torque wrench or something, and make repeated 45 degree angle scrapes against the piece of steel at some set amount of force that replicates accidently bouncing off something at a sideways glance. Then use the caliper to measure the amount of rolling you see. Talking about in-lbs, not ft-lbs here.
You could also find a thin rod, place it on a table, and press at a pre-determined, reasonable weight, and see which edge chips or rolls or whatever the deepest. Or which one leaves the deepest impression in the rod with the least amount of damage.
With the sharpness tester it'd be cool to see you do a salt spray every day, carve some wood with the same pressure and angles, more salt sprays, more carving, over the course of several days and see if there's any truth to edge degradation due to corrosion and if stainless steels are better in that regard in any meaningful way.
I'd also like to see what some tires would do. I've cut through some old steel belted radials to get at some dope before. It didn't destroy the knife but I don't think steels subject to lower fracture resistance would do as well as other steels with a better grain structure and higher impact toughness.
Number 6 sounds shaky at best. Every edge I've ever seen will get messed up pretty quickly doing what you're talking about (acting like you're using the knife as a screwdriver, I think). I'd suggest something more like getting a piece of hardened steel, clamping the knife in some torque wrench or something, and make repeated 45 degree angle scrapes against the piece of steel at some set amount of force that replicates accidently bouncing off something at a sideways glance. Then use the caliper to measure the amount of rolling you see. Talking about in-lbs, not ft-lbs here.
You could also find a thin rod, place it on a table, and press at a pre-determined, reasonable weight, and see which edge chips or rolls or whatever the deepest. Or which one leaves the deepest impression in the rod with the least amount of damage.
With the sharpness tester it'd be cool to see you do a salt spray every day, carve some wood with the same pressure and angles, more salt sprays, more carving, over the course of several days and see if there's any truth to edge degradation due to corrosion and if stainless steels are better in that regard in any meaningful way.
I'd also like to see what some tires would do. I've cut through some old steel belted radials to get at some dope before. It didn't destroy the knife but I don't think steels subject to lower fracture resistance would do as well as other steels with a better grain structure and higher impact toughness.
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Thanks bodog.
Test 6 renamed to "screwdriver test". That's a much better description. I had actually been thinking of flexing the blade at an angle over a rod as you say but was having trouble visualizing the measurements.
What makes me think the screwdriver test is good is that it so directly relates to real-world abuse that I'm sure happens every day somewhere. Also I think I can get some good measurements including the torque required and the amount of flex when cracking begins. And if my setup is simple enough I may be able to measure how much permanent bend each blade takes before cracking. Not that I would ever use my finely built and well researched knife to actually do such a thing, but I think I could get a good feel for how far I'll be able to push the blade out of shape before it's likely to actually bend or break.
I like the scraping test idea too and I think I'll do something close to your description before the dust clears. Similar to the staple drag but sideways, I like it!
Test 6 renamed to "screwdriver test". That's a much better description. I had actually been thinking of flexing the blade at an angle over a rod as you say but was having trouble visualizing the measurements.
What makes me think the screwdriver test is good is that it so directly relates to real-world abuse that I'm sure happens every day somewhere. Also I think I can get some good measurements including the torque required and the amount of flex when cracking begins. And if my setup is simple enough I may be able to measure how much permanent bend each blade takes before cracking. Not that I would ever use my finely built and well researched knife to actually do such a thing, but I think I could get a good feel for how far I'll be able to push the blade out of shape before it's likely to actually bend or break.
I like the scraping test idea too and I think I'll do something close to your description before the dust clears. Similar to the staple drag but sideways, I like it!
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I have owned and used all of the steels listed except AEB-L and Z-wear (honestly have never heard of either). Of what's listed my favorite is CPM20cv, absolutely love that steel. For the price 154 is also a good steel. I'm surprised s30 or s35 didn't make the list. I would put s35vn between CPM20cv and 154 from my experience
There may be another round of tests in the future. MAYBE... I was pretty tired by the time I got all the blades made and I'm not entirely sure I'll want to do that again, hahah..
The whole testing idea came from me wanting to get back into knifemaking. I had made several in ATS-34 and a couple in D2 over 20 years ago and stuff happened that took me away from the hobby. Wanting to get back into it recently I started reading about ALL these steels I'd never heard of. And everybody has their favorites, some say this one chips or that one rusts or whatever but all the info seems a bit subjective to me. Especially if you consider that the steels being discussed are being used by different people, with different shapes and sizes of knives, different sharpening methods and so on and son on...
So I figured the thing to do would be get up close and personal with a variety of steels that might be good candidates for the relatively thin bladed folders I want to make. I searched around and asked some questions and picked out some stuff that looked promising. Some steels were left out because I read about them being brittle or easily chipped edges (CPM-10V and maybe S30V). Also I didn't want to do a bunch of steels that were too similar since after I have experience with these, I can use that knowledge when I hear people making comparisons. Testing all the popular offerings would be great but that would take a ton of resources and my learning goals are directed more toward stuff well suited for the knives I want to make rather than to become knowledgeable about a bunch of stuff I'll never use.
I'm guessing time and expense wise this project by the time I'm done will compare closely with taking a class at the community college. Except this class is all lab time, I get to grade my own test at the end, and I get to keep all the lab equipment.
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I'm excited to see the test results as I plan on making a few small fixed blades this year for Christmas gifts. My first knife I made was a larger fixed blade (3/16") in D2 that was treated by Peters to 61 Rockwell. My mistake as at that hardness it's pretty chippy and a PAIN to sharpen!!
I'm looking to make them from something that will hold an edge, be pretty stainless, and tough enough to hit an elk or deer bone and not chip.
I'm looking to make them from something that will hold an edge, be pretty stainless, and tough enough to hit an elk or deer bone and not chip.
I'm guessing I won't have any test results until about the first week of December and the corrosion test won't be done until the first part of January. I'm excited to see what there is to see and will post results as I have them but don't mess up your schedule waiting for me!
Per Brad's suggestion, the AEB-L, ATS-34 & CPM-154 will go to HRc 59-60. The 20CV, 3V, M4, Z-Wear and Elmax will be 60-61.
Those may not be the numbers a lot of people would choose but I figure Brad has seen more of this stuff than just about anybody and with Peters' reputation I trust his choices. :thumbup:
I also have a couple fun tools on order for getting a good look at what's going on during the tests, check it out...
Digital microscope - saw some pretty good reviews on this one... http://www.ebay.com/itm/121292898829
1000 frames per second camera was way less expensive than I expected. Also well reviewed... http://www.ebay.com/itm/281833825787
I figure those should be fun toys to play with any time, not just for looking at blades
Digital microscope - saw some pretty good reviews on this one... http://www.ebay.com/itm/121292898829
1000 frames per second camera was way less expensive than I expected. Also well reviewed... http://www.ebay.com/itm/281833825787
I figure those should be fun toys to play with any time, not just for looking at blades
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This is an excellent test and thanks for documenting it as you go along.
My 2 cents? Try to get the temps and times on the steels for your own records. The way they acheive a hardness number can vary and the way it is done will affect the attributes of the steels performance. One Z wear rc 61 steel might be set up for max toughness, one for best corrosion resistance , for instance. This information you can keep and not release it, or release it as you choose but it will be nice to have if you want to reproduce or change something in the future. Austenizing and tempering temps can vary and this is what you want to make sure you record at the least. It may surprise some how much the same steel from the same batch performance can vary despite having the two knives hardness numbers at the same tested hardness.
Joe
My 2 cents? Try to get the temps and times on the steels for your own records. The way they acheive a hardness number can vary and the way it is done will affect the attributes of the steels performance. One Z wear rc 61 steel might be set up for max toughness, one for best corrosion resistance , for instance. This information you can keep and not release it, or release it as you choose but it will be nice to have if you want to reproduce or change something in the future. Austenizing and tempering temps can vary and this is what you want to make sure you record at the least. It may surprise some how much the same steel from the same batch performance can vary despite having the two knives hardness numbers at the same tested hardness.
Joe
This thread could end up being an excellent resource as a permanent sticky thread when it's all said and done. Wade, your doing an excellent job documenting your testing intentions and steps in achieving those intentions. Keep up the excellent work. I am enjoying this thread and I know it is something that I will be referring to when choosing steels in the future. :thumbup:
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No worries there, I ordered 3' of CPM 154 yesterday,,,
All the same still excited to see what you come up with!
There's the very first image from my new toy microscope. It's a hair laying across my mini griptilian edge. Not bad for a first shot I think, and the hair measured .0015 on the caliper. Yep, that's awful fine for a hair! Shouldn't have pulled it out I suppose, I don't have so many that I can afford to do that very much, haha. Oh well, looking forward to having a real good look at stuff during the tests.
Tracking shows my package as having been delivered to Peters' today, I just need to keep myself entertained while I wait to get my stuff back :excitement: