BESS test results on coarse edge finish?

S

Strauss95

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Dec 17, 2012
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I got my Bess tester about a month ago and really appreciate the extra data point it gives me. I don't consider myself an expert sharpener, only recently have I focused on trying to perfect my freehand technique. I've gotten much better over the past 2 or 3 months but still have A LOT to learn and improve.

Besides a bunch of full sized bench stones, I also have and use an Edge Pro Apex and Work Sharp Ken Onion with the blade grinding attachment. The Bess tester has driven me back to using my Edge Pro in pursuit of lower scores on the machine, or so I hoped. I struggled getting below 200 BESS on freehand coarse edges, but could get scores down into the low 100's on high grit polished edges. So I went back to the Edge Pro for coarse finished edges and to my surprise I got similar Bess results (180-220). These results are on edges finished with the diamond matrix 650 stone (finishing edge trailing), followed by light stropping on leather (which I have verified the stropping improved BESS score). I typically get 225-275 BESS freehand, finishing on either DMT coarse/fine, or Venev 240/400 also followed by light stropping.

For those of you that have a Bess tester, is it normal for "coarser" edge finishes to score higher, like in the low to mid 200's? I've looked at my edges with my pocket microscope and they look pretty good, certainly no major burr or rounding of the apex. Or am I just terrible at finishing coarse, toothy edges?
 
Hmmmmm ..
Buy some rope , and start slicing ..
What ever ever gives you the most slices is the (?) better edge ( longer lasting ) .

There are two kinds of sharp :
Sharp & Stays Sharp .

I can make some knives scalpel sharp , but the edge is so thin as to be fragile ..
Made one Scandi so sharp just accidentally ( gently ) touching the edge bleed me .. Scary sharp ..
But that edge had the strength of paper ..
I accidently bumped the table with the edge and it fractured .. ( Thin edge )
That knife would have been good for Surgery , but as a working knife = Nope !
Think Two Kinds of Sharp and fit for purpose .

Knife sharpening is a very interesting hobby & skill set !
My free hand suxs , and I always convex the edge . Sure the knife is sharp . but I don't see the ( Stays Sharp ) results from such an edge .
Sure it might feel 5% better feather sticking .. But a nice straight ( true ) bevel / edge might last 100 to 200% longer and strop back rather easily .
So I kind of went with the results ( edge retention & strop back ) ..

40 years ago I was happy with sharp , these days I chase Stays Sharp ! And my sharpening is now driven by results ( edge retention ) .

Right now you are chasing sharp - and that's great ! What's important is that you find what works for you .
So think U Tube and the 100's of sharpening tutorials .
 
Using a TSProf or Ken Onion, I usually see the BESS scores drop from the 200-300 range with coarse abrasives down to 100-150 with fine abrasives. I look at the average of at least 3 measurements with Edge-On-Up, preferably 5 or sometimes more, after stropping on plain leather to remove burrs. A toothy edge is going to give you more variability in the BESS scores, so if you really want a reliable measurement, you may need to measure a lot of different spots on the blade.

But I am not trying to get an edge that's sharp enough to stop with after just the coarse abrasives, so I can't say what would happen if I spent more time on the coarse grits.
 
Strauss95 said:
I typically get 225-275 BESS freehand, finishing on either DMT coarse/fine, or Venev 240/400 also followed by light stropping.
Click to expand...

With a bit of practise and depending on the steel, you will be able to get around about 100 BESS or just under with the 400 Venev and a quick 1 micron stropping. As few strop strokes as is necessary, less is more.
 
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777 Edge said:
With a bit of practise and depending on the steel, you will be able to get around about 100 BESS or just under with the 400 Venev and a quick 1 micron stropping. As few strop strokes as is necessary, less is more.
Click to expand...

That has been my ultimate goal since getting the machine. The Bess tester has been both a gift and a curse lol. I'm happy that it's giving me more information about the quality of my apex, especially troublesome burrs. But, and I knew this was probably going to happen, I feel like I'm "chasing the dragon", finding myself constantly trying to improve my scores. At the end of the day I hope it helps me improve, it's why I bought the machine in the first place.

Before I got the tester I was very happy with my coarse freehand edge results. They would shave hair and loudly cut phonebook paper. The edges worked great in "real use" scenarios (I know that is technically all that truly matters). Knowing others routinely get BESS results as low as 100 on those edges, and finding out my same edges are typically around 250, has me a bit disappointed in my skills. I was even more surprised after getting back on the Edge Pro, seriously taking my time, trying to do everything right, and only improving those same edges down to around 200 BESS. I'm using the slide guide plus retractable magnet, drill stop collar and digital angle cube, edge trailing strokes with diamond matrix stones, and light pressure.

Like I already mentioned, when I run an edge up through higher grits I will typically see results in the 125-150 BESS. I know I could/should see better results with those edges too, but it's the toothy edges that are really puzzling to me right now.

My best BESS result of 105 came from my Stretch 2 in V-toku2 steel. That knife I went "all out" on in hopes of seeing my first sub-100 score, oh so close. I used a full progression of Chosera stones; 400, 1K, 3K, 5K, and 10K at an aggressive angle of 12.5 degrees per side. Followed by stropping on bare cowhide leather on the Edge Pro. Yesterday I sharpened my K390 PM2 at 15 degrees per side running through the entire diamond matrix progression, followed by a 1 micron diamond leather strop that scored 115 BESS. So I know my technique is decent if I can get solid results, it's just these damn coarse edges that are driving me crazy.
 
Hand sharpening on my coarse waterstones I can regularly get BESS scores in the low 100s.
It's a matter of pressure as much as anything else, but thats true with any grit stone.
I start with more pressure, and gradually apply less pressure, and repeat that with the medium and fine stones.
I try to do the same thing if I use my KME (which is rare) and I imagine it works much the same with the EdgePro.
 
My observation is that the Bess Tester is measuring push cutting ability. Push cutting improves with smoother (shinier) tapers and apexes. If you want razor blade results, use finer stones, more strops, and more acute angles.
 
I can regularly get sub-100 BESS scores using my 400 grit CBN wheel on Tormek, followed by a couple passes stropping on the Ken Onion with leather belts. Getting low BESS scores is really ALL about stropping. It's not enough just to knock the burr off, because that leaves a flat where the burr was. You have to knock the burr off and then oh-so-gently hone that burr root down to a sub-micron apex. A lot depends on the particular steel you're working with. With softer and/or less wear-resistant steels, it helps a lot to raise the angle a degree or two for the first few stropping passes (remove the burr) and then come back to the sharpening angle to finish up (hone out the burr root).

Deburring is trickier when you stop at coarser grits because coarser grits tend to make bigger burrs. But with practice it's absolutely possible to create a hair-whittling toothy edge.
 
This is exactly the type of info I was hoping for, thank you! Any more help/advice is appreciated!
 
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