Sharpness testing for (possible) new YouTube channel -- your thoughts?

[PeterS84]

Hi all!

I've been toying with this idea for a couple of months and I'm now getting pretty close to pulling the trigger and moving forward. Before I do, I would really like some feedback from my BF friends as to whether or not you think this type of testing would be valuable given the wealth of data that's currently available on BF and YouTube.

I'm considering doing steel testing using an Edge-On-Up PT50A. My idea for testing is as follows:

Take a knife, for example a Spyderco Paramilitary 2 in S110V. Measure thickness behind the edge with calipers. Sharpen to a course finish using a controlled angle sharpening system like the EdgePro or KME (say DMT course/325 grit). Test initial sharpness as measured with PT50. Then do a series of controlled cutting test such as 20 cuts through standard Amazon box cardboard (12 inch cuts, measured pieces of cardboard). Test sharpness again with PT50 and record difference from initial level. Then do a series of cuts through 5/8" manila rope -- start with 25 cuts, test sharpness again. Do 25 more cuts through rope, test again. Then compare the beginning sharpness, sharpness after cardboard, and final sharpness after all cuts and determine the % change.

Then re-sharpen the same knife at the same angle, but polish to a very high level -- say 0.1 micron as the final abrasive grit. Perform the same tests and compare the % decrease between the course and fine edge to determine which degrades the least in use.

What do you guys think of this protocol? Any suggestions? Would this type of testing be valuable to you?

I don't want to exactly duplicate the tests I've already seen which tend to involve extensive rope cutting, etc. until a knife stops being able to reliably slice a certain test media. I'm thinking that by doing the same number of cuts in the same types of materials, the tests will indicate what type of finish would be most durable under certain types of EDC use based on objective sharpness tests with a calibrated tester.

Thanks in advance for your feedback on this!

 

[katanas]

You lost me at PT50; I thought that was a staple gun. If you tell me what it is, I might be able to make a sensible suggestion (unless you feel "if this guy has to ask, I don't want his suggestions") which I would understand.

 

[Mo2]

Jeff's been using this system for a few months now and it's very unreliable

https://www.youtube.com/channel/UCY_JhULUKTR38qk2OXxCV6A

 

[PeterS84]

You lost me at PT50; I thought that was a staple gun. If you tell me what it is, I might be able to make a sensible suggestion (unless you feel "if this guy has to ask, I don't want his suggestions") which I would understand.

The PT50 "Edge-On-Up" is a device which has a standard test media that you cut. Then, based on the amount of weight/force required to cut the test media it gives a numeric reading which correlates to levels of sharpness. Ex: a reading of 100 would theoretically be sharper than something with a reading of 300. If you Google it you'll find lots of links to vendors and probably YouTube videos. I'm not an expert on them as I haven't yet bought the device.

 

[PeterS84]

Jeff's been using this system for a few months now and it's very unreliable

https://www.youtube.com/channel/UCY_JhULUKTR38qk2OXxCV6A

I watched both of those videos just now and my take away from what he said is, essentially, that using a very consistent technique when cutting is of paramount important and that the clips are more reliable and less variable than using the spool. That all said, I wouldn't be opposed to using strictly the clips and marking on the knife with a pen where the test cut will be done to remove as many variables as possible from the equation. Even if there is some variability, I think the PT50 is probably the most scientific means we have at this point of objectively testing the sharpness of an edge. I'm sure my understanding on this will evolve somewhat once I have a chance to test it myself (if I end up moving forward with this project).

Seems to me that marking the location where the blade meets the test media and pressing straight down directly above that point with the knife running perfectly parallel to the PT50 is as close as scientific/controlled as I could be with regard to this type of testing.

I'm not looking at this as an opportunity to tout my own sharpening abilities and show how sharp I can make things. Rather I'm looking at it as a semi-scientific way to demonstrate the way in which blades of varying materials dull or degrade relative to initial measured sharpness in both fine and course edge finishes. For example, if I were to show that an S110V blade loses 20% of its sharpness being put through a test starting with a polished finish vs. showing that it loses only 10% of its initial sharpness when starting with a course finish, that might be a good data point to add to the information which is already available from other testers. Likewise if I were to show that S110V loses 20% of its initial sharpness after going through the test cuts but VG10 loses 35% of its initial sharpness, that too would be interesting. Granted, these numbers are all hypothetical at this point. Maybe that's not of interest to the majority out there, but to me it seems like it would be an interesting study.

 

[Mo2]

If you watch his videos since then the numbers all vary. Plus you having a channel isnt going to help anyone. The numbers you get will be for your knife and not someone else's and they will also vary no matter how many times you try.

Not seeing any point to making a yt video about this subject.
Unless you have a sharpening business that you want to use this gimic to show customers there finished product.

I don't think it's a good method for what your looking for.

 

[PeterS84]

If you watch his videos since then the numbers all vary. Plus you having a channel isnt going to help anyone. The numbers you get will be for your knife and not someone else's and they will also vary no matter how many times you try.

Not seeing any point to making a yt video about this subject.
Unless you have a sharpening business that you want to use this gimic to show customers there finished product.

I don’t have a sharpening business and have no intention of starting one.

I don’t think we’re seeing eye to eye on this but I do appreciate your feedback. Definitely food for thought as I continue to consider whether this is worth doing.

 

[Mo2]

I don’t have a sharpening business and have no intention of starting one.

I don’t think we’re seeing eye to eye on this but I do appreciate your feedback. Definitely food for thought as I continue to consider whether this is worth doing.

We don't see eye to eye because the testing method is flawed.

 

[PeterS84]

We don't see eye to eye because the testing method is flawed.

Ok, I’ll bite. What do you suggest would be a better way of objectively and repeatably testing the sharpness of a knife before and after cutting that gives a numerically quantifiable result?

 

[Mo2]

Ok, I’ll bite. What do you suggest would be a better way of objectively and repeatably testing the sharpness of a knife before and after cutting that gives a numerically quantifiable result?

Good question. I was hoping this machine would. But sadly it's not. I don't think there is a good method that's available.

Have you seen Cedric Ada gear and outdoors? He uses paper. Not the idea method either. But he does show how many cuts with coarse or mirrored edges before it has issues cutting into the paper.

No method is going to be perfect but that scale isn't going to be a good idea either.

 

[katanas]

Many years (too many) ago I was involved in psychological testing for a defense contractor. One thing we determined was that attaining perfect test parameters was not feasible. I believe that the more variables people test, the more likely a well founded decision can be made. So, for me, if what you test AND how you test it is somewhat different from what has previously been done you are helping. A big key is to NOT be repetitive. Good luck!

 

[PeterS84]

Good question. I was hoping this machine would. But sadly it's not. I don't think there is a good method that's available.

Have you seen Cedric Ada gear and outdoors? He uses paper. Not the idea method either. But he does show how many cuts with coarse or mirrored edges before it has issues cutting into the paper.

No method is going to be perfect but that scale isn't going to be a good idea either.

I have watched his videos pretty extensively. I think they provide some very good anecdotal information regarding certain capabilities of the various alloys he tests. I was hoping to find another means of testing which doesn't just test "how many cuts until dull" but rather tests "how much dulling happens from a certain amount of cuts." That and I would like to save my arms/hands from having to do 1,000 cuts to test Maxamet and the like.

 

[PeterS84]

Many years (too many) ago I was involved in psychological testing for a defense contractor. One thing we determined was that attaining perfect test parameters was not feasible. I believe that the more variables people test, the more likely a well founded decision can be made. So, for me, if what you test AND how you test it is somewhat different from what has previously been done you are helping. A big key is to NOT be repetitive. Good luck!

Thank you! That's exactly what I was aiming for -- similar but examining the same question from a different angle to provide some additional data.