Some CATRA test results

Can you go into detail on the sharpening procedure using the 120 grit belts, specifically how to remove/prevent burr formation? I tried this a couple of years ago, but was never able to completely remove the burrs that formed.
 
Will look forward to it. Using the CATRA tester allows you to focus on the prep, results, & conclusions for sure.
 
Thanks a lot for sharing this! Your precision reminds me of my days working in a laboratory. This kind of independent research is both time consuming and expensive so thanks again!
 
Hardheart, first, I echo what everyone else is saying... fantastic work and I appreciate you passing along your findings. I am very curious of what you found with the 120 grit, 20 degree edge tests. With the understanding that you only had a data population of 2, do you have a gut feel of how they would perform if you had a larger sample size i.e. do you suspect a large spread? With a difference as large as you found, I would guess that those 2 data points would be considered statistical outliers if thrown into the other populations. If so, then even with a sample of 2 could lead you down a path of "something is different with this". Maybe the rough surface is acting like serrations and tearing vs. cutting (though CATRA is a compressive force)? Really, really intersting and pretty cool find. It seems like it would be the opposite vs. a polished edge. I hope you plan to include this find in your future, collecting more data to support the find.

Ohh, will you share which type of steel you studied?
 
Bob Katilus said:
I am very curious of what you found with the 120 grit, 20 degree edge tests. With the understanding that you only had a data population of 2, do you have a gut feel of how they would perform if you had a larger sample size i.e. do you suspect a large spread?
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No, the sampling is too small and the changes too many to make a direct comparison. But, the increase in media cut was similar to the other differences between edge angles. The 7 degree drop from 27 to 20 increased media cut close to the same amount as the 7 degree drop from 34 to 27. The 16 degree drop from 50 to 34 also coincides with the 14 degree drop from 34 to 20. 120 grit is only about a 250-300% increase in particle size over 45 micron. 3 micron to 45 is a 1500% increase, and the average impact on results was far less than 10%, and was also in favor of the smaller particle size. I cannot be conclusive at all, but I doubt the grit played a large factor when compared to change in edge angle.
 
I'd love to see some before and after micrographs of those edges. Might not tell much, but you never know...
 
I've reread this thread a few times looking for what alloys were tested. What alloys were the blades in this test? Am I blind?
 
Well, a non-update. I got all the blades back and contacted a local metals testing lab. Unfortunately, I spoke with their metallurgist and he said they wouldn't be able to cut the blanks and that they were very busy. Really felt more like a blow off than anything. I'll try to get in touch with some university staff in state next. If that doesn't work, I'll try a couple names I know of in the knife community. Hopefully I can get this additional info.
 
There is one here that I use for work that was happy to give me a quote for some knife testing late last year. I can send an address and info if you're interested. They quoted a reasonable price for sectioning a blade for microhardness from edge to spine, checking for softening from belt sander sharpening.
 
me2 said:
There is one here that I use for work that was happy to give me a quote for some knife testing late last year. I can send an address and info if you're interested. They quoted a reasonable price for sectioning a blade for microhardness from edge to spine, checking for softening from belt sander sharpening.
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That would be great, thanks. The metallurgist had also said they would charge $200-$400 per blade if they had the time, so any better than that would be nice.
 
hardheart said:
That would be great, thanks. The metallurgist had also said they would charge $200-$400 per blade if they had the time, so any better than that would be nice.
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Sounds like someone was trying to retire on what you wanted to have done to me.
 
Nearly a year old now, but still comes to mind sometimes. Any updates?
 
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