Edge Retention/Rolling Test Stand

[Rupert Lucius]

Greetings.  New member here, at least my first post here on the BESS forums.  I come via the Tormek forum and am a novice sharpener but a far more accomplished machinist.  

I like the notion of testing for edge rolling.  I think the proposed device/method is mostly a good idea.  I agree with KG about using a PT50 to measure the force. I was thinking of this in a different manner, one where the measurement of force occurred through the use of a device on the top of the ram, much like a hydraulic press.  I think the PT50 idea is better as it is already a known entity and a standard of comparison.  

I share a concern expressed by March Reich about how slicing should be part of the testing method.  I think this because it seems to me that it isn't just pressing downward that rolls the edge, but lateral movement along with pressing down.  I think his concern about pressing only at 90º is valid as well, as that also is not how knives get used and edges rolled.  

I think that a knife, per se, may not be the best test edge, but rather something known to much more standardized, such as a DE razor, utility knife blade or a single-edged razor with the reinforce backbone.  These could be tested for sharpness out of the box and rolled and tested again.  But I wonder if they shouldn't be dulled and then sharpened by some standard process and then tested.  I think they should not be tested in just a single location, but rather, drawn along the piece of steel to simulate actual use, measuring and keeping the force uniform, and probably at a slight angle so as to cause the edge to roll to one side.  Probably they should be tested both vertically with only downward force and also at an angle and then also with drawing along the steel strip.  I know that gets into a lot of testing, but I think these are all things that should be considered when deciding how to begin the testing. 

Thanks,

Rick Kr

Well, I see that I posted after having read only the first page or two, not realizing the most recent posts were at the end on page 14 (at this time).  I'll have to go thru and read the rest.  My comments may not have much relevance or contribute anything new, given the extensive discussion that I was unaware of.  I'll do a better job of reading more be fore posting in the future.  

Rick

Rick Kr -

Your expressed thoughts are 100% of my feelings.  Thanks for coming aboard at this juncture.

You and Mark R. are 100% spot on.

I, NEVER return any knife to service before  several  cuts through 1/2" manila rope, then testing the edge for sharpness.

That said testing may be BESS or using a roll of PAPER adding machine tape.  Never  have seen a paper roll of adding tape with any "bias" NONE never.  The same for telephone book paper (no bias).

We should discuss true edges and false edges at some later date.

Thomas (Edgepal) opinion would be appreciated.

Mark and Thomas both know how to read a edge and understand what they  are reading.  Many sharpeners that know it all - in my opinion can not read the edge - the edge is also always talking to the sharpener - just listen.

Again thanks you for your posts - you are spot on again my opinion.

As always
Rupert

[Bud]

I've been following along on this thread since the beginning Mr. Rick KR so maybe can offer my understanding. The edge rolling test is done like a slicing test in that the bearing rolls up against and then down the edge and tries to push it over. The edge tester then measures how much the edge rolled. It's not like cutting rope in that the test is not designed to tell how much the edge might have been worn away by cutting the rope. Maybe cutting rope is just another way to roll the edge.  Maybe rope has abrasive in it and actually grinds metal away, I don't know. I think that if someone wants to know how much their edge has been ground away from cutting something that that would be a different kind of test. If I have this test wrong then someone can correct me. Hope i have it right and this is helpful to you.

[Rupert Lucius]

I've been following along on this thread since the beginning Mr. Rick KR so maybe can offer my understanding. The edge rolling test is done like a slicing test in that the bearing rolls up against and then down the edge and tries to push it over. The edge tester then measures how much the edge rolled. It's not like cutting rope in that the test is not designed to tell how much the edge might have been worn away by cutting the rope. Maybe cutting rope is just another way to roll the edge.  Maybe rope has abrasive in it and actually grinds metal away, I don't know. I think that if someone wants to know how much their edge has been ground away from cutting something that that would be a different kind of test. If I have this test wrong then someone can correct me. Hope i have it right and this is helpful to you.

Thanks Bud

for helping me to refocus -

Off for medical appointments.  Will tune in later today.

Rupert

[Rick Kr]

Thanks, Bud.  I am getting the sense of it.  I'm up to page 8 so far. 

Rick

[EOU]

" I think that if someone wants to know how much their edge has been ground away from cutting something that that would be a different kind of test."  You did a great job in your summarization with regard to both the mechanics and the scope of the test Bud and so won't try to improve on your explanation.

[Bud]

Thank you EOU. Sometimes I get it right. Rupert should know that I give free medical advice too.

[Rupert Lucius]

Thank you EOU. Sometimes I get it right. Rupert should know that I give free medical advice too.

You two Guys are just too much.

We will soon be correlating the new product (edge roller) findings - to the price of a knife enabling the consumer to know what they are getting in value?

Rupert

[EOU]

That caused a chuckle Bud. Our understanding is that Rupert is forwarding his medical history and files to you FedEx for your review.

Rupert - "We will soon be correlating the new product (edge roller) findings - to the price of a knife enabling the consumer to know what they are getting in value?"  If you subscribe to the theory that edge rolling is the primary contributor to dulling edges then you may just be able to remove the question mark from the end of your sentence.

[Mark Reich]

I've been following along on this thread since the beginning Mr. Rick KR so maybe can offer my understanding. The edge rolling test is done like a slicing test in that the bearing rolls up against and then down the edge and tries to push it over. The edge tester then measures how much the edge rolled. It's not like cutting rope in that the test is not designed to tell how much the edge might have been worn away by cutting the rope. Maybe cutting rope is just another way to roll the edge.  Maybe rope has abrasive in it and actually grinds metal away, I don't know. I think that if someone wants to know how much their edge has been ground away from cutting something that that would be a different kind of test. If I have this test wrong then someone can correct me. Hope i have it right and this is helpful to you.

Hello Mr. Rick Kr, Welcome to the Forum! It's really great to have you here.  

I'm barely a novice machinist, but I have several good friends (and one of my heroes) who are magnificent machinists. I've always been in awe, and have tremendous respect for your trade. I finally acquired a full size digital knee-mill several years ago, and it is my favorite single piece of equipment, spanning three well appointed shops. I appreciate your comments, and can easily recognize your point of view. 

Mr. Bud, you are correct that cutting rope is not the same as rolling the edge. They are basically the two ways that edges are affected to a point where they no longer perform as desired. IMHO, one is not necessarily more significant or important than the other.

These two properties of edges have been recognized for a very long time. They are called "edge stability" and "abrasion resistance". Of the two, abrasion resistance is something that people have a better understanding of, because it's always been more practical to quantify edge degradation by cutting stuff.

Most often you'll hear of people testing edges by cutting cardboard, but I don't understand why. Cardboard is un-quantifiable. It varies a lot in thickness, density and composition. It is recognized to be abrasive, but to an unknown degree. It's free. That's it's best attribute.

There is a reason very few people are willing to actually test cutting performance. It is a lot of difficult, tedious work. To the best of my knowledge, and Mr. Mike can correct me if I'm wrong, I've probably been using a BESS machine to Measure edge degradation far longer and far more than anyone else, but I'm a neophyte when it comes to cutting rope. 

Many Decades ago, Mr. Ed Fowler, one of the most well recognized bladesmiths in America, and a founding member of the American Bladesmith Society, decided to try cutting rope instead of cardboard. Rest assured, Mr. Ed Fowler has been as serious about quantifying and improving every aspect of blade performance as anyone else I've ever heard of, and he has been whole-heartedly working non-stop on it for nearly 50 years.

When I decided I wanted to make the best knives I possibly could, I pulled out all the stops. I went directly to the most well recognized and respected bladesmiths in the US, and faithfully apprenticed under them. Money was no object, other than I know you generally get about what you pay for, so I spent as much money as it took.

I learned as much as possible very quickly that way, and I learned by far the most from Mr. Ed Fowler. For one thing, I learned not to shy away from hard work. If you truly want to make the highest performance blades, you have to figure out the best way to test them, then you have to have the balls to do the required work to the best of your ability. I've been faithfully testing Abrasion Resistance for many years, so I probably do know something about it. 

I was very fortunate to run into Mr. Mike several years ago. I was so totally convinced that the BESS machines were revolutionary that I immediately bought a dozen KN100s. I knew one very big advancement had been made, and I wasn't going to have to cut rope until the blade was dull anymore. I could make 100 cuts instead of 500, and Measure edge retention. Or abrasion resistance... same thing. That was the initial concept, and I haven't changed my stance one iota.

One of the main reasons we use manila rope is that over the Decades, it has proven to be clean enough and consistent enough to give repeatable results. It's actually pretty gentle to the edge. There is absolutely no "grinding down" of the edge. If you happen to be testing a blade that's worth $500 to $2500 (which are almost the only blades we test), it's very significant that rope doesn't mar the sides of these blades like cardboard. 

Another item of prime importance you mention is the question of whether rope "...is just another way to roll the edge". Well, it's never rolled a properly heat treated HEPK 52100 blade in 50 years. When some of us on this forum were testing the Work Sharp M3 edge denting device, I cut a Bunch of rope with many different knives. No Rolled Edges. Period.

Obviously edges do roll. I've seen rolled edges on soft stainless steel from cutting cardboard. Every edge will roll every time it hits something relatively hard. No edge survives cutting on a ceramic plate or granite counter top.

The SET edge rolling machine produces edge stability failure every time. It's the first machine of it's kind, but it is newer than new, and frankly, nobody knows exactly what this will lead to. I'm sure it will lead to some very interesting, conclusive findings. I know I'm excited to see what I can discover.

[Rick Kr]

Hello Mr. Rick Kr, Welcome to the Forum! It's really great to have you here.  

I'm barely a novice machinist, but I have several good friends (and one of my heroes) who are magnificent machinists. I've always been in awe, and have tremendous respect for your trade. I finally acquired a full size digital knee-mill several years ago, and it is my favorite single piece of equipment, spanning three well appointed shops. I appreciate your comments, and can easily recognize your point of view.

Mark,

Thanks for the welcome. It is good to be here. 

I hope I did not mislead anyone with my comments about being a machinist. That comment was relative to my experience/status as a very novice sharpener more than a claim to being a good machinist.  I learned machining in my father's high precision, exotic materials, short-run production machining/tool and die making shop in the 1960s.  I didn't do much more until beginning again as a home shop machinist in 2000.  Since then, I have built on what I learned earlier.  Since working in my father's shop, I have never worked professionally as a machinist.  I was a professional fish biologist.  The machining knowledge certainly came in handy there. 

I have a digital knee-mill, albeit a small one, and am in the market for a full sized one.  I currently have one lathe running in my shop, a Monarch 10EE (1946 vintage, very nicely restored, with DRO).  In my opinion, this lathe is one of two ultimate home shop machinist lathes.  I am exceedingly fortunate to have it.  

I have now read the entire thread and have learned a LOT.  Just as I was starting to get a clue about sharpening to finer levels of sharpness...   ...the world may be shifting on its axis.   I anxiously await results and further discussions. 

Rick