Hey all,
Getting fall-like around here, which means I need to get back in the shop and start playing with some ideas.

I came across some O1 tool steel scraps from previous blades, or blade attempts.
None of them would make good stock for a full blade, but they should have some use.

Here is the idea that I have been thinking about, and it may or may not be a good one.

Also in the scrap bin is a fair amount of 304 Stainless.


I was thinking of TIG welding a 1/2" piece of O1 onto a SS blank, then shaping, then HT.
The O1 being the blade edge.

Is this just a ridiculous idea?

Often when I am welding carbon steels, I will use 316L SS filler rod as it is said to make a stronger weld.

Over the years, I have TIG welded a lot of SS and have developed some skills in minimizing warping and such.

Any thoughts are appreciated, but please don't send a van with dudes in white coats to pick me up

I use power tools for sharpening, but I don't throw strop away because it's good to touch up. 

Recently I bought JENDE 4 & 0.5 micron PDP emulsion that is waterbase. And I have sharpeningsupplies paddle strop.(https://www.sharpeningsupplies.com/12-XL...-P314.aspx) 

I guess the smooth side(very similar with smooth side of Surgi-sharp leather belt) is better than suede side for waterbase emulsion. Has anyone tried it? I applied 4 micron PDP emulsion to smooth side of Surgi-sharp leather belt to remove burr but it doesn't work properly. 


   
Smooth side, 

   
Suede side.

   
This is my second belt grinder Viel S-5-M(1/3HP)


   
It's 4mm thick Robax ceramic glass. 


   
I applied Jende 4 micron & 0.5 micron PDP emulsion to linen belts, but it couldn't remove the burr.(Left is 0.5 micron, Right is 4 micron) 


   
So I tried to 4 micron PDP to Surgi-sharp leather belt, but the result was not different.(Right belt)

Left belt is Surgi-sharp applied with Tormek PA-70. It killed the burr and honed the edge very well. I can get 50~70 BESS with my kitchen knife. But I think 2700 SFM is too fast for using it.

I got my new edge on Up sharpness tester and was very excited to try it out.

First test: Spyderco small Persian in my pocket. Sharpened on sharpmaker up to extra fine rods at 15 dps and then used on random things the past few weeks. Result: 300

Second set of tests. Byrd Cara Cara (1?) that I reprofiled on the Edge Pro to 11-12 dps with 140 grit diamond plate. I then moved to the standard edge pro waterstones

180 grit: 471
320 grit: 230
600 grit: 157
1000: 179
0.5 micron diamond paste on bovine: 137

It looks like I need some more work on fine grit sharpening as the 1000 was worse than the 600. Either that or I got lucky on the 600 or tested a wire edge.

The low grit stones are a little different than the ones that are currently included, I think. I looked at the Edge Pro and it says “Ben Dale 3-99.” It’s been around a while.

What is Edge Stability? >>
By Larrin Thomas

Inspired by the thread by Mike and Grepper http://www.bessex.com/forum/showthread.php?tid=371

What wire edge is

Well-known 2 steps in sharpening a knife are apexing and deburring, and deburring is more challenging since it determines how sharp and stable your edge will be.

There is one very special zone at the base of the burr, right between the burr and the apex, designated as LOW on the below optical microscope image showing layers of the burr (the image is from the above thread).


After you deburr the edge, the base of the burr turns into the wire edge.
The wire edge is often regarded as a structural continuation of the apex – it is its sharpest but also the weakest structure. From a logical standpoint this poses straightforward reasoning – the burr formation is the result of plastic deformation, why would one expect the steel at the base of the burr stay the same as the apex?

In the ultra-sharp sharpening we distinguish more steps in deburring, namely: exposing the base of the burr also known as wire edge, and cleaning the apex of it.

The following optical microscope images show a burr off a coarse abrasive that is easily felt by brushing a finger across the edge, and next to it a blade with the wire edge that you cannot see and cannot feel. (By courtesy of Tony Spielberg, USA)




The wire edge on SEM edge-on view (all SEM images are by courtesy of Todd Simpson scienceofsharp.wordpress.com)


“Feather burr” and “Foil edge” are two more edge geometries that can be created in the finishing stage of removing the burr – these two are near synonymic and are a product of edge-trailing honing at the edge angle; shown on the following optical and SEM microscope images.




We can recognise presence of the wire or foil edge by the edge behaviour in cutting stuff.
An obviously ultra-sharp edge that whittles hair will start a smooth cut but end with tearing, or show clean cuts alternating with ragged - indicating a weak edge folding in the process. If the edge is not cutting well, it can only mean two things: either it has not been fully apexed, or there's a burr or crushed wire/foil edge getting in the way.
The wire edge crushes under a minimal load by mushrooming seen on SEM microscopy.



What we see on the BESS sharpness tester?

Because the wire edge is too weak to cut the test line, it crushes on it and, as we increase the downward pressure, mushrooms against the line allowing to apply more pressure onto the widening point till the line gets finally severed – in the point of testing we see a micro-dent in the edge with the mushroomed apex displaced to the dent bottom, and the sharpness reading is times worse than we would expect by seeing the same edge whittle hair and push-cut rolling paper.



A knife that fails early is the result of a wire edge that hasn't been properly removed.
A good sharpener knows how to apex and deburr the edge; an expert sharpener knows how to clean the apex of the weak wire edge not rounding it.
The wire edge is very common in edge-trailing deburring as too often the base of the burr is not removed completely. It is just so fine that it is not detected by the 'finger method' most people use. The end result is the wire edge that dulls extremely quickly once the wire gets mushroomed with the first cuts.

How do we clean the apex of the wire edge?

It's a bad idea to simply draw the edge through a wood block, rubber or cork to “rip off” the wire edge. If you do, the metal crud will build up on the front of the slice, and you'll be dragging the rest of the edge through the crud and this, together with breaking off of ledges of material along the edge, will roughen the edge and worsen sharpness.

An edge-leading pass on an ultra-fine bench stone can accomplish the wire edge removal, but at the risk of micro-chipping and abrading off the apex when done by inexperienced hands. A shortfall of this method is that you are introducing a new microscopic burr.

We remove the wire edge by honing with fine diamonds or CBN and raising the honing angle very slightly, from 0.4 to 2 degrees – the softer the steel, the higher the angle. The edge only needs to “sink” the apex into the compressible material, and you can do this on leather, balsa, hard felt or a paper wheel just as easily as on a hanging denim strop loaded with a fine honing compound – the microscopic diamonds will cut at the base of the burr.

Only once you eliminate the base of the burr, there is no more wire edge. A correctly deburred edge shows nothing except the clean scratch pattern going to the end of the apex.
Optical and SEM microscope images of a cleaned edge follow.




Uncertainty

Methods to assure completeness of deburring and removal of the wire edge we have at our disposal, on the one hand, and the miniscule nature of that edge on the other, bring us to the point of uncertainty, IMHO.

In all honesty, where a freshly sharpened edge scores over 100 BESS we can not tell for sure whether this results from some residual wire edge or not – because at this BESS score only SEM imaging is able to exclude the weak apex mushrooming against the test line.
Only when the BESS score taken on the standard test media line is near 50 BESS, i.e. that of uncompromised DE razor, we can be absolutely sure that the edge apex is clean of the wire edge, and this is the only instrumental indicator we have readily available at present.

Experiments on wire edge removal

I experimented on a budget stainless steel kitchen knife - WiltShire brand.
We know these knives as producing that nasty malleable mutant burr that is very difficult to clean off, and I used to be happy if I could get them score 170 BESS.

Sharpened on Tormek, the edge was set at 13 dps on #1000 CBN wheel.

Then honed on a paper wheel with 5-micron diamonds at the edge angle - honing mainstream stainless steels this way invariably produces a microscopic feather burr, similar to pictured.
At this step we thin away the original burr and gain access to the base of the burr.


The top layers of the burr are removed but leave the base of the burr intact and still stuck to the edge in the form of the wire edge. The wire edge, by its genesis, is the very first layer of the burr laid down and is really well stuck to the edge apex. We think this layer at the base don’t flip with the rest of the burr in the process of deburring.

I then cleaned the hardly visible fine feather burr on a rock-hard felt wheel with 1-micron diamonds on Tormek, using our Frontal Vertical Base for honing away from the wheel, similar to shown on the next picture, only in place of the legendary AL MAR imagine the cheap WiltShire kitchen knife.

The experiment plan was in repeating the sharpening-honing-cleaning sequence, gradually raising the felt honing angle, and recording the resulting BESS scores.
Grinding and honing angle was controlled with our computer software for Tormek and paper wheels.



Off the #1000 CBN the edge burr scores 250 BESS.
After the 5-micron diamonds paper wheel the edge feather burr scores near 500 BESS; micro-denting is easily detectable in the point of testing. The high BESS score is result of the feather burr crushing and mushrooming against the test line.

Now 1-2 passes on the felt wheel with 1-micron diamonds on Tormek, alternating blade sides.
At this step we hone away the flimsy feather burr and clean the apex of the wire edge.

Felt wheel at the exact edge angle = 100 BESS
Felt wheel at +0.4 degree higher angle = 80 BESS
Felt wheel at +1 degree higher angle = 175 BESS
Felt wheel at +1.5 degree higher angle = 140 BESS
Felt wheel at +2 degree higher angle = 80 BESS
Felt wheel at +2.5 degree higher angle = 120 BESS

I then repeated the two best results, i.e. re-sharpened the edge on #1000 CBN, honed on the 5-micron diamonds paper wheel at the edge angle, and then on the felt at +0.4 vs +2 degrees higher angle, after the felt wheel finishing the edge on a paper wheel with CHROMOX for final cleanup.
Felt wheel 1-mcrn diamonds @ +0.4 degree = 90 BESS >> CHROMOX = 100 BESS
Felt wheel 1-mcrn diamonds @ +2 degrees = 80 BESS >> CHROMOX = 55-60 BESS, hair-splitting.

We see that for the lower-end mainstream stainless steel the best cleaning of the apex is achieved by high-angle honing at 2 degrees higher than the edge angle.
In this case, the edge set at 13 dps, we cleaned at 15 dps, and by the BESS score near 50 BESS we seem to have cleaned off the wire edge.
For that lower end s/s steel, 55 BESS is a record sharpness score on an obviously stable edge.

How I interpret the other failed sequence of "Felt wheel 1-mcrn diamonds @ +0.4 degree = 90 BESS >> CHROMOX = 100 BESS" - I think it tells us that the base of the burr had not been honed away completely on the felt, and the paper wheel with CHROMOX, rather than cleaning the apex, added volume to the remnants of the wire edge, turning it into the foil edge; when it pressed against the test line and mushroomed we saw that increase in the BESS score.

How I interpret changes in the BESS score with the raise of the honing angle on the felt:
Felt wheel at the exact edge angle = 100 BESS      <- feather burr removed, we are nearing the base of the burr
Felt wheel at +0.4 degree higher angle = 80 BESS  <- the base of the burr exposed
Felt wheel at +1 degree higher angle = 175 BESS   <- adding volume to the base of the burr through burnishing
Felt wheel at +1.5 degree higher angle = 140 BESS <- adding volume to the base of the burr
Felt wheel at +2 degree higher angle = 80 BESS     <- the base of the burr cut off, the apex exposed
Felt wheel at +2.5 degree higher angle = 120 BESS <- rounding the edge apex

If you're a convert to "toothy" edges like we are then proper burr removal becomes the center of your world. We like toothy edges because they are easy and fast to create using, typically for us, a single grind process with a 80 - 180 grit ceramic belt on the Kally. The actual grinding process may take only 30 seconds to a minute. Now the work begins though, proper removal of the burr and removal of certain elements and artifacts of the burr can be a real challenge. The goal is to remove the burr completely without significantly reducing the tooth in the edge. We've been experimenting here with faster and surer methods of getting from A to B and the first order of business for us is to understand, as completely as possible, what the constituent components of burr formation are.
 
Burr formation does not appear to be some cataclysmic event. Formation of an easily recognizable burr seems to be a process. While there are those who seem capable of "seeing" a burr at its earliest formation stages we do not count ourselves among them without the aide of magnification.  In practice, we have to rely on "feeling" the burr. What we have learned is that burr formation begins long before any of us can actually detect it tactilely. 
 
We designed an experiment that builds on the work already established by our good friend Grepper. Grepper has shown us the enemy through his microscopic work many times in other threads. In our communications with Grepper we have non-affectionately named this enemy "LOW" or "line of weld". This is not because it is a "line of weld" but rather because it has the same appearance as a "line of weld". It is a booger indeed. Visible only via properly lighted microscopy, stout and firmly attached to the edge apex. Proper removal of this LOW will result in a 50 - 75 point improvement in BESS scores. Here's is a LOW image taken by Grepper with text added by us;

                             

These layers are stuck together somewhat but not firmly bonded. When normal deburring methods are employed, more often than not, the top layers of burr are removed but leave the LOW intact and still stuck to the edge. The LOW has such a low profile that subsequent deburring attempts using common methods and materials are unable to pick it up and stand it up so that it can be removed. It can be picked up though and just to be prove it, Grepper performed this little trick and then took the photo. He used the point of an exacto knife to pry the burr up. We tried the same thing with the corner of a DE razor blade but it wasn't stiff enough to turn the LOW over. A single edge razor blade was and we were successful in standing the LOW up in the same fashion that Grepper had. Here's Grepper's picture with our remarks; 

                         

The LOW seems to be the first layer of burr laid down and it seems to be really well stuck to the side of the edge. It's also well attached to the edge apex. Subsequent grinding passes just seem to add to the volume of the burr. To support this theory we ran the following experiment. First we set the rest on our Kally at a fixed angle and then sharpened a knife and removed all the burr including the LOW. We did no leather refinement to the edge which seems to always be good for another 30 or 40 points but still the edge measured 150 and 155 and even though the belt we used was 80 grit.
Then we ground this already sharp edge again. But first we colored the edge  black (grind side) with magic marker to make certain that the belt removed metal all the way to the edge. We made just one very light pass on just one side of the edge. There was no detectable burr present. Then we took a picture of the ground side.

                         

Not much to see other than the residual of the black marker buried in the grooves of the original grind marks.  So we flipped it over for a picture of the opposite side of the edge;

                           

And there we find a nicely formed LOW. Any subsequent and additional passes with the belt will add to the volume and height of this burr. As the burr is flipped back and forth during the grinding process it grows until it can be readily felt with a thumb. In the picture above, we couldn't feel it. If you strop the LOW on leather pad or belt it usually won't come off. If you persist and are finally able to remove it, a significant amount of tooth will be lost in the process. We are working with Grepper on ways to efficiently remove the LOW while preserving tooth and some methods do show a lot of promise. More on that later but in the meantime, we have identified the enemy. Grepper recently reported in an Exchange thread sub 100 BESS scores on a very average knife. In that case, proof that the enemy can be defeated.

Over the years, I have ownd three belt grinders. All of them happen to use 1x42” belts. I have believed that the larger 1x42 belt size was better suited for more serious work than the smaller 1x30 belt size. Last night I discovered the you tube channel of Cliff Curry (Curry Custom Cutlery). He has done some serious work with several 1x30 belt grinders, including changing bearings; truing wheels, and mofifying a Harbor Freight unit to work with the Viel scissors attachment and a DC variable speed motor. 

I was impressed enough with his videos to begin to think my position on 1x30” belt grinders. I like the smaller size Tormek T4. Is my opinion of 1x30 belt grinders not well founded?

Ken?

Over the years, I have ownd three belt grinders. All of them happen to use 1x42” belts. I have believed that the larger 1x42 belt size was better suited for more serious work than the smaller 1x30 belt size. Last night I discovered the you tube channel of Cliff Curry (Curry Custom Cutlery). He has done some serious work with several 1x30 belt grinders, including changing bearings; truing wheels, and mofifying a Harbor Freight unit to work with the Viel scissors attachment and a DC variable speed motor. 

I was impressed enough with his videos to begin to think my position on 1x30” belt grinders. I like the smaller size Tormek T4. Is my opinion of 1x30 belt grinders not well founded?

Ken?

Experiments on Knife Steeling

Quality honing steels are made of wear-resistant steel hardened to 65-67 HRC and chrome-plated.
Rockwell Hardness Difference Comparator tells us that steels are by at least 50% harder than the typical kitchen cutlery for which they're designed. The sharpening steels are designed for low-alloy stainless kitchen cutlery and mainstream knives, but limited as to the types of steels they will abrade, and are useless for high-end wear-resistant steels.

The two types of steels are smooth and grooved.
Smooth, also called polished steels, are used for deburring and re-aligning a rolled edge.
Grooved, also called ribbed, sharpening or honing steels used for light sharpening. These sharpening steels grinding power is rated by their “cut”: regular, fine and ultra-fine cut. You may think of the grooved/ribbed steels as single-cut files with the teeth running parallel with the rod, but with one important difference - the surfaces of the fine-cut ribs are smooth, and they increase rate of metal removal by reducing the contact area and increasing the local pressure rather than abrasion, which explains their remarkable burr-free honing action.

Butchers and chefs typically have 2 steels: one polished and one grooved; while meat plant workers usually are equipped with a single duo/combination steel that has both polished and grooved faces.

Spring-loaded twin smooth steels aren’t as good because they hardly hit the edge - it's natural to draw your blade too deeply, so the twin rods ride against the shoulder of the primary bevel, rather than the edge; in meat plants they are chiefly used to clean off grease deposits from the blade.

Renowned sharpening steels brands are F.Dick, D.Russell and Isler.

Butcher’s polished and grooved steels



Combo steel


STEELING TECHNIQUE

Both the polished and grooved steels are necessary for a chef or meat worker to get through the day. Steeling technique is different for the polished and grooved steels, and correct steeling is a major skill needed to maintain the sharp edge.

A very sharp edge is maintained for hours of cutting by steeling on the smooth (polished) rod. But there comes a time when the edge apex gets weak from repeated realigning with a smooth steeling rod over that time; it rolls much too easily, even under pressure from your thumbnail, and the smooth steel rod can't fix that. That's when the meat worker abrades the edge apex off with the grooved sharpening steel and resets the edge. Then again just the smooth steel is doing the upkeep.

The smooth steel is also used to deburr a freshly sharpened edge. Some advanced users actually prefer steeling over stropping, on the knives that respond to it, as there's less risk of rounding the new apex this way, as can happen on a loaded strop.

Steeling is always done edge-leading.

Smooth rod technique for edge re-aligning (recovering a rolled edge): 2-4 heel-to-tip light passes alternating edge sides, at the edge angle.

Grooved rod technique for resetting the edge: 4-10 heel-to-tip firm and brisk strokes alternating edge sides, at the exact or slightly higher angle.

Video: https://youtu.be/itS-KhyEK7w


SCANNING ELECTRONE MICROSCOPE (SEM) STUDIES

In his Experiments on Knife Sharpening Prof. John D. Verhoeven studied use of smooth steels in deburring on a stainless steel hardened to 60 HRC.

Todd Simpson (scienceofsharp.wordpress.com) shared his observations on use of honing steels for edge re-aligning.

Prof. Verhoeven
Prof. Verhoeven found out that the best deburring with a smooth steel is achieved by 2 back-and-forth light passes alternating edge sides, and the result depends on whether the burr is off a #600 or #1000 grinding wheel.

#600 – large burr
"The SEM micrographs show that the action of the steeling on the 600 grit blades is one of wrapping the burr formed by the wheels around to one side of the edge and deforming it up against the face. The net effect is a slightly straighter edge with significantly reduced roughness in face views and a more uniform and slightly thinner average edge width in edge views."

#1000 – small burr
The smooth steels do deburr, but:
"The steeling process does not offer an improvement in edge quality with respect to edge straightness, edge roughness or edge width over that obtained with the fine 1000 grit."

Increasing number of passes causes ledge breakout as the edge of the blade is very susceptible to fracture as well as plastic deformation in the steeling process.
"…with 15 b&f passes it was very common to observe breaking off of ledges of material along the edge… Reducing the number of b&f passes to 2 dramatically reduced both the density of such ledge break-out regions along the edge as well as the size of the ledge regions… In summary, the effect of the number of passes was fairly clear, the lowest number of passes studied, 2 b&f passes, produced the best edges."

It was also shown that too high a steeling angle, higher than 10 degrees over the edge angle, is detrimental to fine edges - e.g. for a 20 dps edge, a steeling angle of over 30 dps will be detrimental, while within 20-30 dps is alright.

Unfortunately, Prof. Verhoeven’s data have little practical application because they cannot be extrapolated onto kitchen cutlery and meat processing knives which typical blade hardness is near 55 HRC as opposed to the 60 HRC used in his study, while the HRC60 blades are hardly ever steeled in real life.

Todd Simpson
Todd's observations are extremely valuable, and not only because SEM studies of knives are rare.

"I've only looked at steeling on a few hard knife steels and carbon steel utility blades.
What I observed is that honing rods (including polished steel) primarily cut a micro-bevel; however, there is some burnishing or "pushing around" of steel occurring as well. My speculation is that unlike softer steels that are work-hardened by steeling, the hard steel is "work-softened" and it's only that soft steel (near the apex) that can be pushed around."

In our understanding, what Todd sees on the SEM, is the time when the edge apex gets weak from repeated realigning with a smooth steeling rod and when the edge must be reset with a grooved sharpening rod by abrading off the apex.

The following SEM images made by Todd are of a dull edge, steeled on smooth and grooved steels – in both cases metal removal and micro-bevelling are obvious; Todd gave the blades 10 strokes on the steels before taking them to the SEM.


Dull edge


Smooth steeling


Grooved (abrasive) steeling

OUR EXPERIMENTS

We studied deburring and re-aligning using a 10" F.Dick Combi Steel (polished/fine-cut).

Deburring was studied on SWIBO knives of HRC 57-58.

Recovering a rolled edge was studied on common brands of professional meat processing knives of HRC 55-56, and SWIBO knives of HRC 57-58.



All knives and blades were sharpened at 15° degrees per side (dps); we maintained the constant angle of steeling by placing the steel on a base angled at 15 degrees from the vertical, and holding the knife/blade as near vertical as possible while drawing it along the steel.



Effect of steeling was estimated by a BESS sharpness tester PT50A.
Controlled edge rolling was done on the BESS SET Structural Edge Tester.
Video: https://youtu.be/EdGOSWjrM0E

DEBURRING

Deburring was studied on SWIBO knives (HRC 57-58) sharpened at 15 dps on #200, #400, #600 and #1000 CBN wheels on Tormek.

Steeling was done edge-leading on the smooth (polished) faces of the F.Dick Combi Steel, at the edge angle, in two modes:
- by 2 heel-to-tip light passes alternating edge sides; and
- by 2 back-and-forth light passes alternating edge sides (total 4 passes each side).

Edge sharpness was measured off the wheel before steeling, then after the steeling done in the first mode; the edge was then steeled in the second mode – improvements in sharpness scores can be interpreted as the burr reduction.



* The #1000 edge, steeled by 2 back-and-forth passes each side gave the best sharpness of 179 BESS on the smooth steel; the burr is not visible any more.

By the BESS reading we can tell that after steeling the #1000 edge has a weak wire edge, because actual edge sharpness is better than what the we see on the instrument display – this edge push-cuts Tally-Ho cigarette paper longitudinally, which is indicative of a sharpness of 110 BESS or better, and the fact that the sharpness tester shows a worse score tells us that the very edge apex gets crushed over the test line – when the apex gets "mushroomed" in the point of testing, this allows to apply more force before the test line severs, giving a falsely higher score on the display. As an illustration, the following SEM image shows a "mushroomed" edge apex:


By courtesy of Todd Simpson

Even though on our SWIBO knife of HRC 57-58 we could not fully repeat Prof. Verhoeven’s results he obtained on HRC 60 s/s blades using #600 and #1000 wheels, the smooth (polished) steeling does help to deburr after #1000, probably by what Prof. Verhoeven described as "wrapping the burr formed by the wheels around to one side of the edge and deforming it up against the face".

We’ve carried out one more experiment to check effect of steeling on the grooved fine-cut faces as described above in the Steeling Technique for resetting the edge.


The last deburring technique makes the edge shaving sharp, and can be used in the absence of more advanced deburring means.


RECOVERING A ROLLED EDGE

Common brands of professional meat processing stainless steel knives were sharpened at 15 dps (30° included) on Tormek, edge set on #1000 CBN wheel, and deburred on a paper wheel with 5 micron diamonds (#3000).
Grinding angle of 15 dps was set with the help of our software for Tormek http://knifegrinders.com.au/05Equipment_scripts.htm

Deburring was done on the paper wheel at a 0.4° higher angle, i.e. at 15.4 dps; honing angle was controlled with our software for paper wheels
http://knifegrinders.com.au/11Shop_PWsupport.htm
As we found out in a separate study, this is the best deburring angle for these knives. Honing with fine diamonds at the exact edge angle usually produces a weak wire edge on mainstream stainless steel knives of HRC 55-58, detectable by BESS sharpness scores higher than they should be because of "mushrooming" the weak wire edge against the test line in the point of testing – honing at a little higher angle eliminates this problem by cutting off the weak apex.

Edge angle was verified with a CATRA laser protractor



Controlled edge rolling on the BESS SET Structural Edge Tester was done by series of 5 cycles to the 50th cycle, and then from the 50th to 100th cycle by series of 10 cycles; overall each blade received 100 rolling cycles.

Rolling cycle explained
The impact roller is a linear bearing slant at 10° to the horizontal base or in other words at 80° to the plane of the blade clamped vertically.
Standard impact assembly weight is 150 grams.
The impact roller is lowered at "A", then moved (rolled) over to "B" and then back to "A".
A-B-A is one cycle.

After each series of rolling, edge sharpness was measured, and the edge was steeled by realigning technique described above i.e. on the smooth (polished) steel by heel-to-tip light passes alternating edge sides, and the sharpness measured again.
Our preliminary tests have shown that the best sharpness recovery after rolling on the SET tester is achieved by 4 alternating passes on the smooth steel – and this was the standard through all experiments.

The edge was reset once after the 50th rolling cycle by the edge-resetting steeling i.e. on the grooved fine-cut steel by 4 heel-to-tip firm strokes alternating edge sides, and finishing on the smooth steel with 1 heel-to-tip light pass each side. After the last 100th cycle we did one more steeling on the grooved steel to see if there is any change in response to abrasion.

To better the data validity, we were taking sharpness measurements on 2 points of the blade, obtaining two sets of numbers and averaging them in each case.

Earlier, we had the same knives tested on the BESS SET Structural Edge Tester without steeling, and used that data as the baseline.

Knives used in this experiment:


We’ve got masses of numbers, averaged them across all the three knives, and built a graph.
Results are very interesting.
Link to raw data >>
Link to averaged data >>

The below graph is built on average sharpness scores of the three knives: SWIBO, GUISSER and VICTORINOX – the grey baseline shows average edge rolling without steeling, and the blue line shows average edge rolling with steeling; grooved abrasive steeling is shown by the red arrow.



The most interesting findings:

500 BESS is the score of a blunt knife – without steeling all of the tested knife brands reached this benchmark within the first 50 rolls, while with steeling none of them has blunted even after 100 rolls.

Following edge reset on the grooved steel, sharpness recovery by smooth steeling increases by 2-3 times.
Abrasive (grooved) steeling resets the edge apex back to the elastic state.

Systematic steeling prevents the edge apex transition to irreversible plastic deformation.

Our experiments have also shown that higher HRC is associated with better response to smooth (polished) steeling, while lower HRC – to grooved (abrasive) steeling. In other words, softer knives of HRC 55-56 perform better with frequent grooved steeling, while harder knives of HRC 57-58+ perform well with smooth steeling and can be dulled by overuse of the abrasive steel.

Mike Brubacher, the inventor of the BESS Edge Sharpness Testers and SET Structural Edge Tester has noted that "... edges that have been rolled up to 200 points, we are able to restore those edges to their original sharpness reading simply by stropping and straightening the edge on a solid surface."
We cannot observe this on the SET tester because of the more than 200 points impact, but in real life steeling does return the rolled edge back to shaving sharp.

Steeling recovers the rolled edge through these mechanisms:
- straightening structural elements of the apex by realigning some and deforming others up against the face;
- micro-bevelling through adhesive wear on smooth steels, and abrasion on grooved;
- work hardening.


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