Thread: Experiments with the BESS system

Originally Posted by rob streeper

I don't. It was apparent to me that the incident angle at which the blade intersects the filament makes a difference. Droop in the filament had a big effect. Preventing the blade from sawing the filament is also important. I can see a number of improvements that can be made to the BESS jigs / systems to improve repeatability.

So did you deliberately test different points on the blade? If so then this is a semi external reproducibility which is itself interesting.

E.g. consumers would rather see a BESS number next to an electric sharpener, than marketing allegations of how sharp it makes your knife.

I assume you are talking about knife nerds, most consumers would know a bess number from a lotto number.
A bess number without open and transparent test data (not having to pay for it) is just marketing in my book.

Originally Posted by BobL

So did you deliberately test different points on the blade? If so then this is a semi external reproducibility which is itself interesting.

Yes, I purposely tested at different points along each blade.

Originally Posted by BobL

It seems to me that this is all wood workers really need to do. If they need some sort of a reference point they can just calibrate new rolls of filament against a fresh razor blade.

I'd be happy to take a 300m roll of fishing line for $6 shipped, divide it into ~17m segments ($0.36 cost each) and sell them to you for $19 if you like, I'll even 'certify' it.

Rob, you miss the point of standard and communication.
If my sharpening workshop returns a customer his high-end knife telling him it is 'razor sharp' - this is no more than bragging.
When the knife is returned with a BESS score certificate of 50, the same what a safety double-edge razor scores, it's a fact.

When I publish a study on knife turnover in a Sydney abattoir the results are readily understood by a Thai poultry processor or at a Canada meat processing plant, etc.

For anyone who's interested the balance I used is commonly available on eBay. https://www.ebay.com/itm/Mettler-PM4...8AAOSw3utY4V61
Not much more expensive than the BESS instruments and much more useful. These are very robust and great for a variety of woodworking tasks such as mixing epoxy, determining densities, weighing tools and packages and so on.

Originally Posted by KnifeGrinders

Rob, you miss the point of standard and communication.

Standards represent expert consensus. Further, standards are published. Refusal to publish is a failure of communication.

Originally Posted by KnifeGrinders

If my sharpening workshop returns a customer his high-end knife telling him it is 'razor sharp' - this is no more than bragging.
When the knife is returned with a BESS score certificate of 50, the same what a safety double-edge razor scores, it's a fact.

It's an anecdote at best.

Originally Posted by KnifeGrinders

When I publish results on knife turnover in a Sydney abattoir they are readily understood by a Thai poultry processor or at a Canada meat processing plant, etc.

Show us YOUR data now.

Originally Posted by BobL

It seems to me that this is all wood workers really need to do. If they need some sort of a reference point they can just calibrate new rolls of filament against a fresh razor blade.

Ya know, it seems to me that this is all much ado about nothing much at all (the system, not Rob & Bob's research and discussion).

When one of my chisels or plane blades is blunt, I hone them up starting with whatever is required and finishing with 12,000 grit diamond paste on a cast iron block (usually 3-5 up/back strokes).
It is entirely repeatable and predictable.
I do not need to know a "number" of how sharp it is because it cuts as it previously did.
Nor do I need yet another step in the process.
It is as sharp as it gets in my workshop with my system.

Why on earth would I want to dick around determining if it's within 10% (or whatever) of the previous sharpness, especially when it's about to lose it again anyway? ("ok, not quite there this time, give another couple of strokes next time") It's just adding time and bench clutter to an already slightly aggravating interruption (having to stop planing to re-hone).

Any woodworker worth a small part of their salt will know when the edge is ready for use, and any who doesn't will not be capable of getting the required result anyway, without more experience in sharpening - i.e. a machine to tell them the bleeding obvious is not much use.

There is no market for this system for woodworkers. Perhaps there may be a market for professional edge makers or resharpeners, so they can say "this edge is blah blah" or so they can tell some guy on the other side of the world that their knives are sharper than his.

Originally Posted by KnifeGrinders

When I publish a study on knife turnover in a Sydney abattoir the results are readily understood by a Thai poultry processor or at a Canada meat processing plant, etc.

But does anyone care about this? Isn't the Thai poultry guy too busy cutting up chooks to care whether a Sydney Butcher has sharper knives than him?

Originally Posted by FenceFurniture

Why on earth would I want to dick around determining if it's within 10% (or whatever) of the previous sharpness, especially when it's about to lose it again anyway? ("ok, not quite there this time, give another couple of strokes next time")

Brett,
Some of us jes cain't help ourselves (https://en.wikipedia.org/wiki/Where_...as_gone_before)

I'm one of those people who say "Why?".

Originally Posted by FenceFurniture

There is no market for this system for woodworkers. Perhaps there may be a market for professional edge makers or resharpeners, so they can say "this edge is blah blah" or so they can tell some guy on the other side of the world that their knives are sharper than his.

True, only useful for the nerd types. I've gotten along fine for years without a way to assess sharpness.

I always get a kick out of people who challenge data with nothing but assertions.

The next phase of my work will look at edge holding ability. Bring some marshmallows, could be interesting, or not.

Originally Posted by rob streeper

The next phase of my work will look at edge holding ability. Bring some marshmallows, could be interesting, or not.

Yes, well there lies a legitimate need for an edge measuring device/system - you are doing research. A little like Brent Beech and his assessment of plane blades from various manufacturers some years back.

I guess telling us about your next project also tells us why you were so interested to learn the data behind this system (i.e you're looking for a system, so you were interested to learn......well nothing really, as it turns out, until you started your own tests.)

It's just all a little suspicious - marketing overpriced fishing line, lack of data. Maybe there hasn't been any data taken? I haven't read all the detail (because I know when my edges are sharp.....), but the general feel I get is that it revolves around the pressure required to cut a specified piece of line. Maybe that's not quite correct, but assuming that I'm close, wouldn't other factors be also at play, such as included angles? For example, for a meat cleaver (for use either in Phuket or Perth or Pleasanton) the inc angle might be 20° which is a whole bunch tougher than 8°, but would require more pressure to cut the line than 8° would (because a cleaver is all about impact more than pressure).

It (the marketing) reminds me of the deodorant stick I use. I deeply suspect that it's 10c worth of Epsom Salt made into a mono-crystal and sold for $12. The miracle lies not in what the product actually is, but in being able to discover what it is despite the obfuscations and deflections.

Assuming of course that my dataset is representative of reality, the only thing we really know here is how easily a set of blades I have cut fishing line.

On the other hand we don't apparently have anything better so why not forge ahead?

Originally Posted by FenceFurniture

Ya know, it seems to me that this is all much ado about nothing much at all (the system, not Rob & Bob's research and discussion).

When one of my chisels or plane blades is blunt, I hone them up starting with whatever is required and finishing with 12,000 grit diamond paste on a cast iron block (usually 3-5 up/back strokes).
It is entirely repeatable and predictable.
I do not need to know a "number" of how sharp it is because it cuts as it previously did.
Nor do I need yet another step in the process.
It is as sharp as it gets in my workshop with my system.

Why on earth would I want to dick around determining if it's within 10% (or whatever) of the previous sharpness, especially when it's about to lose it again anyway? ("ok, not quite there this time, give another couple of strokes next time") It's just adding time and bench clutter to an already slightly aggravating interruption (having to stop planing to re-hone).

Any woodworker worth a small part of their salt will know when the edge is ready for use, and any who doesn't will not be capable of getting the required result anyway, without more experience in sharpening - i.e. a machine to tell them the bleeding obvious is not much use.

There is no market for this system for woodworkers. Perhaps there may be a market for professional edge makers or resharpeners, so they can say "this edge is blah blah" or so they can tell some guy on the other side of the world that their knives are sharper than his.

Those were my exact sentimonies!

In my head, knowing if my chisel is 5 BESS or 10 BESS is irrelevant... what's more relevant is how much better a 10 BESS chisel will perform vs a 5 BESS chisel or whatever the measurement is... and if it does indeed perform NOTICEABLY better, does it blunt twice as fast? and is that rate of decay worth the extra time and effort to get 5 extra BESSES? (really they should have come up with a better term of measurement, BESS doesn't exactly roll off the tongue... might i suggest changing it to "Chazwazza's"?)

Firstly, a huge think you to Rob for doing this testing and to Bob for his comments.

comments come to mind
1. In practical terms there doesn't appear to be much difference - at least with the Blue Spruce chisel -- between sharpening to 5000, 8000 or 10000 grit.

2. Again with reference to the Blue Spruce tool, some of the test results are sufficiently away from the mode as to suggest they are outliers and could be removed from the average.

3. as a means of investigating achieved sharpness vs the grit used, the BESS methodology seems to be relatively inexpensive (at least compared to electron micro-photography)

4. To somewhat echo Brett -- thanks Rob for showing me that an edge off a 5000 grit stone is probably sharp enough most of the time.



and thanks again Rob for doing the investigation.

@Rob - BESS and similar sharpness testers cannot be used for evaluating cutting performance, edge holding ability etc as these depend on the blade geometry, angle and profile - for that testers like CATRA's are used that cut through a standard sheet of a test media, not a line.

@FenceFurniture - Thailand started using the BESS edge sharpness testers in their poultry industry long before Australia and New Zealand

@Both of you - You reminded me of people asking for data behind a Rockwell hardness number - it is just a number on an agreed scale, HRC scale or other.
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