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PT50- Slight Mods
Forum: Relevant General Discussion
Last Post: EOU
7 hours ago
» Replies: 38
» Views: 519
It's Summer
Forum: Knife Making & Bladesmithing
Last Post: Mark Reich
8 hours ago
» Replies: 4
» Views: 57
Edge Straightening Tools
Forum: Relevant General Discussion
Last Post: EOU
Yesterday, 09:55 AM
» Replies: 3
» Views: 64
EDGE RETENTION/ROLLING PA...
Forum: Edge Sharpness Testing
Last Post: grepper
06-14-2018, 05:14 PM
» Replies: 28
» Views: 804
Meat Plant Research
Forum: BESS
Last Post: KnifeGrinders
06-08-2018, 12:57 PM
» Replies: 15
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Opinions and advice on my...
Forum: Edge Sharpness Testing
Last Post: Mark Reich
06-08-2018, 09:58 AM
» Replies: 20
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Edge retention by hardnes...
Forum: Edge Sharpness Testing
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06-08-2018, 01:20 AM
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shaving sharp
Forum: Relevant General Discussion
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05-31-2018, 06:38 PM
» Replies: 6
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EDGE STABILITY IN BUTCHER...
Forum: Edge Sharpness Testing
Last Post: KnifeGrinders
05-24-2018, 10:40 PM
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4000th Post Challenge
Forum: Knife Making & Bladesmithing
Last Post: Mark Reich
05-24-2018, 08:38 PM
» Replies: 6
» Views: 421

 
  Edge Straightening Tools
Posted by: Mike Brubacher - 06-14-2018, 02:10 PM - Forum: Relevant General Discussion - Replies (3)

Here's a question for KG and anyone else who might want to kick in. I watched a video recently of this product being used in a meat processing facility.

[Image: 420010_1200.jpg]
Is this the sort of edge straightening tool used in Australian plants KG? This one happens to be made by ERGO. If you're familiar with this or similar tools would be interested in hearing what you know.

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  It's Summer
Posted by: Mike Brubacher - 06-14-2018, 02:02 PM - Forum: Knife Making & Bladesmithing - Replies (4)

You can tell that's its Summer. No crossing guards at the elementary school in the morning and the grass always looks like it needs to mown now. You can also tell by the decreased traffic on the BESS Exchange. People have been cooped up all winter sharpening knives and now it's time to head outdoors where you can use them. We'll keep the home fires burning here until the leaves start falling so everyone have a good and safe Summer!

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  shaving sharp
Posted by: Ken S - 05-26-2018, 10:33 AM - Forum: Relevant General Discussion - Replies (6)

Earlier this week I had a minor heart attack. I give high marks to all of the capable and friendly people who cared for me.

My one regret is that I was not carrying a hair popping sharp pocket knife with me. The most painful part was when all the adhesive contact tapes for the monitoring were pulled off. I wish I had shaved all my chest and arm hair. 

A more practical solution would have been for the medical staff to have offered to shave it early in the procedures.

Ken

ps All is well. I was given a clean bill of health.

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  PT50- Slight Mods
Posted by: Mark Reich - 05-24-2018, 01:16 PM - Forum: Relevant General Discussion - Replies (38)

I recently finished my first spool of media for my fabulous new PT50. Congratulations EOU, the PT50 is really a lot faster and easier to use than the original KN100! 

I had a couple small issues with the PT50A. I don't know how the PT50B is different, so this may or may not be applicable.

I don't always have a pair of reading glasses around when I need them, so I was having a little difficulty with a couple things. 

First, it wasn't easy for me to always get the edge of the blade in the slot of the blade rest. Sometimes I would drag the edge across the hard plastic, which probably doesn't make any difference to a 150 edge, but I've been working with fine edges lately. The rest also seemed a little tall, so I decided to customize one of the two knife rests that were included.

I took the magnet off so I could accurately cut the height down to the bottom of the groove, and super glued a wafer of cork on top, which can't affect even a super fine edge. Not having to hit the slot just makes things way easier for me. 

 [Image: FDpnPvS.jpg] 
It wasn't always easy for me to get the media under the plastic nut on the yolk because of the groove machined into the yolk. I just thought it would be easier if I didn't have to back the plastic nut out of the groove, so I ground the groove off flush.

[Image: 89ffFGd.jpg]


A couple things- It was easy to grind the groove off perfectly with the bottom of the yolk on the table of a grinder, but I wanted the extra traction of the scratch pattern being horizontal instead of vertical. This was a little trickier, because I had to lay the yolk on it's side, which is round, and eyeball it. I'm not sure how much difference that makes, but I barely need to snug the lock screw, so it seems to work considerably easier to me.

*Special Note* If you grind the groove off the yolk, do not forget to blow the screw hole out with compressed air! There will be metal filings in the hole, which will ruin the plastic threads. Also, the edges of the top groove will be sharp after grinding, so make sure to ease them with fine sandpaper or a buffer.

Just my 2¢.  YMMV

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  Meat Plant Research
Posted by: KnifeGrinders - 05-21-2018, 09:35 PM - Forum: BESS - Replies (15)

We are lucky that the meat plant has allowed to publish part of our research we did for them.
Meat plants are secretive about everything that gives them a competitive advantage, and as soon as they realize benefits of BESS sharpness testers, they become reluctant to share, especially about the savings.

The article published in the Australian Meat News has about 1/4 of our findings, due to the magazine format and restrictions imposed by the meat company.

The company runs 2 meat plants, an abattoir and training in meat processing, website www.becampbell.com.au

The meat plant in Sydney, Australia processes 2300-2500 pigs a day, from the carcass to ready retail products, portioned and packed.
Knives are used in 3 operations:
- boning;
- dividing cuts; and
- portioning slicing.
This research was on boning knives.

PDF spread >>

[Image: AMN1.png]
[Image: AMN2.png]

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  Edge retention by hardness, carbon content and wear-resistant alloys
Posted by: KnifeGrinders - 05-19-2018, 05:23 AM - Forum: Edge Sharpness Testing - Replies (3)

In the below chart we've put together SET-tested steels which composition we know.
SET Results are sorted from the best to the worst.

Even without fancy graphs, just looking at the numbers, it is clear that edge retention correlates primarily with the content of wear-resistant alloys, then with the carbon content, and finally with the HRC.

[Image: steel_comparison1.png]

However, when we look at the resistance to initial rolling in the first 5 impact cycles, we see that, though wear-resistant steels do withstand rolling by about 30% better, there is no correlation between the wear resistance and resilience to initial rolling.

[Image: steel_comparison_Phase1.png]

The high-vanadium edge sharpness quickly moves beyond the shaving range to just sharp. In the first impacts a 10% vanadium edge apex rolls to the same extent as a 3%, and both the 3% and 10% vanadium edges lose their initial keenness almost at the same rate as a mainstream knife. Considering that the impact assembly weighs just 150 grams, isn't that astonishing?
Higher wear-resistant blades win as stayers, but are equal sprinters.
As one of our readers has commented: "Which may explain why s110v loses it's keenness rather quickly but is able to keep a working edge for a long time"

To make things worse, you cannot steel "supersteels" back to shaving sharp as you can with softer steels – they are too hard for this, and the bent apex stays there as a tiny scraper.
For this reason, professional meat cutters prefer mainstream steel for their knives, as a meat plant veteran commented: "When working in the boning rooms as a boner, after sharpening my knife it needed to shave after steeling for necessary sharpness to work with. Steeling is necessary to get through the day."

It is getting really intriguing what Mike's SET testing of the A2 steel hardened to a range of HRCs will show.
The main lesson we've learnt so far is not to assume anything, yet I wonder if the A2 data will show similar pattern of equal initial keenness loss, but better long-run retention with the increase in HRC or not.
A2 is a high carbon and primarily Molybdenum steel, and if the pattern is different, it will tell us that what we've seen is vanadium-specific and shouldn't be generalized to other wear-resistant alloys.

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  BESS in Industry
Posted by: EOU - 05-17-2018, 04:25 PM - Forum: BESS - Replies (10)

As many of you are aware the BESS enjoys a growing roll in industry. While many of the industrial applications we are engaged in are easily recognized some would surprise you. Many have certainly surprised us. We've recently finished talks and will begin joint testing for edges used commonly in agriculture. The potential design and purpose of  these edges is lengthy but, in cooperation with our international manufacturing customer, we'll begin with a single and very common tillage tool used by farmers across the US and Canada.

We'll be testing for optimum initial sharpness as well as measuring edge degradation in field use. We anticipate that our new SET unit will be utilized as part of the optimization effort as well.

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  Edge Rolling in High Vanadium Knives
Posted by: KnifeGrinders - 05-17-2018, 06:14 AM - Forum: Edge Sharpness Testing - Replies (5)

Edge Rolling in High Vanadium Knives Sharpened with
Aluminium Oxide versus CBN/Diamond

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PLAN

The plan is to use the SET method (Structural Edge Testing) to test edge resistance to rolling in high vanadium knives with vanadium content ranging from 1% to 10%, sharpened with Aluminium Oxide versus Cubic Boron Nitride (CBN) & diamond abrasives.
 
The goal is to obtain experimental data for the ongoing discussion among knife enthusiasts whether sharpening high vanadium knives with abrasives other than CBN and diamond enhances their edge propensity to rolling.
There is no smoke without fire, and the more people own high-end knives, the more we hear about this. The most plausible explanation is that the common abrasives weaken steel matrix around the vanadium carbides – being too soft for the vanadium carbides they only abrade the steel around the vanadium carbides rather than polish them.
 
A priori expectation is that we will see no significant difference in edge rolling before some threshold content of vanadium. Obvious practical application would be to allow the common abrasives for sharpening steels with lower than that vanadium content, and use exclusively CBN and diamond for higher.
 
Vanadium carbides are not the only high wear resistant carbides - niobium, cobalt, molybdenum and wolfram (tungsten) carbides also are, and should respond similarly to abrasives.

SET METHOD

Structural Edge Tester (SET) is a method and device developed by Edge On Up for testing edge stability. In a nutshell, the edge is subjected to controlled rolling, the extent of which is quantified.
Edge sharpness tester used in the study: PT50A Industrial.

[Image: SET_tester.JPG]

Impact 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.

[Image: SET_testing10.JPG]
[Image: SET_Cycle.png]
The impact roller is lowered at "A", then moved (rolled) over to "B" and then back to "A".
A-B-A is one cycle. 

See our video on YouTube https://youtu.be/EdGOSWjrM0E

Our standard SET testing procedure is to measure edge sharpness after every cycle for the first 5 cycles (Phase I), then after every 5 cycles to 50 cycles (Phase II), and then (i.e. from the 50th to 100th cycles) after every 10 cycles (Phase III).
Where by the 100th cycle the edge hasn’t blunted to 500 BESS, we continue rolling, measuring sharpness every 20 cycles till reach 500 BESS.

Sharpness of the majority of knives (apart from CPM “supersteels”) nears or exceeds 500 BESS, i.e is rendered blunt, by the 100th impact cycle, allowing us to watch the full life cycle of the edge within one 11-minute test.

The testing procedure yields additional information about events happening in the edge through the three distinctive phases:

·        Phase I “Elastic deformation” from the 1st to the 5th impact cycle, when sharpness is measured after every cycle – considering that interval between subsequent impact cycles is about 30 sec, this break in impact allows the edge to partially recover from rolling. This phase takes about 2.5 min.

·        Phase II “Elasto-Plastic transition” from the 6th to 50th impact cycle, where the edge gets 5 impact cycles between sharpness measurements – edge is challenged for resistance to plastic deformation. The elastic deformation transits to plastic here. Weaker steels simply crash in this phase. This phase takes 5 min.

·        Phase III “Plastic deformation” from the 51st to 100th impact cycle, where the edge is continuously rolled 10 times before each next sharpness measurement, testing the edge stability to permanent rolling. This phase takes about 3.5 min.

Key indicators:
§ Overall average sharpness over 100 impact cycles;
§ Average sharpness in the Phase I (elastic deformation) - calculated as an average of sharpness scores in the first 5 impact cycles;
§ Sharpness by the end of the Phase II (elasto-plastic transition) – calculated as an average of 3 sharpness scores: after 40, 45 and 50 impact cycles;
§ Number of impact cycles to turn the edge blunt at 500 BESS (resistance to permanent rolling).

Overall, each SET test takes 11 minutes to estimate life cycle of the edge.

SELECTION OF KNIVES
 
For the purpose of a comparable selection, we selected steels with minimum content of other than Vanadium alloys. The table below illustrates how we picked steels from the knives in our disposal – those in bold were selected for this research.

[Image: selection2.png]

As a CONTROL TEST, to see if the sharpening abrasive as such imparts any difference, we sharpened in the same way a vanadium-free but high-carbon knife in SR-101 steel (Busse Swamp Rat knife), its chemical composition follows.
[Image: SR101.JPG]
[Image: control_comp.png]

SHARPENING METHOD
We know from our previous SET tests that the results depend on the edge angle and initial sharpness.

All knives were sharpened and honed the same way on Tormek T-7 and T-8 machines at the same edge angle of 12 degrees per side (24° included) and to the same sharpness within 80-100 BESS.
Sharpness of 100 BESS is midway between safety razors and utility blades; for those new to BESS - the lower the score, the sharper is the edge, e.g. a safety DE razor scores 50 BESS, and utility blades 150-200 BESS.

Edge angle was ground with the help of our computer software for Tormek and verified with a CATRA laser protractor.

[Image: applet1.png]
[Image: laser_12dps.JPG]

The first sharpening was made with Tormek stock 250 mm aluminium oxide wheels, and honing on the Tormek leather wheel with the Tormek honing paste, known to be chiefly of aluminium oxide particles averaging 3 microns in size.
Edge bevel was ground on a freshly trued SG-250 wheel (#220), and edge set on a dedicated SG-250 wheel graded to #1000 with a diamond plate.

[Image: T7.JPG]
[Image: Grading1000.JPG]
[Image: Grading.JPG]
grading to grit #1000

Honing angle was controlled with our FVB for Tormek-7 and computer software.
First round of SET testing was run on these knives.

[Image: applet2.png]
[Image: FVB.JPG]

The same knives were then re-sharpened on Tormek-compatible 254 mm CBN wheels, and honed on a dedicated Tormek leather wheel impregnated with 3-micron diamonds.
Edge bevel was ground on a CBN wheel #400, and edge set on a CBN wheel #1000.
For honing on Tormek with diamonds we normally use a rock-hard felt wheel, but this time used the leather wheel to hone the same way as in the first sharpening.
Second round of SET testing was then run.

[Image: T8.JPG]


To match sharpening done with aluminium oxide and CBN/diamond, in each sharpening we set the edge with 2 passes on the #1000 aluminium oxide or CBN wheel, and were giving the edge the same amount of honing of 2-3 slow passes across the leather wheel, alternating sides.

With this setup, in sense of achievable sharpness I didn’t find aluminium oxide much inferior to CBN or diamonds in sharpening high vanadium steels, though definitely slower in bevelling – having ground the edge angle on a coarse SG wheel, we set the edge with two passes alternating sides on the SG wheel graded to the grit #1000, and honed/deburred with 2-3 slow passes on the leather wheel with the Tormek honing paste – in all cases the sharpness we got was within 80-100 BESS.
It was faster to bevel the edge angle on a coarse CBN wheel, but by setting the edge with the same two passes on the grit #1000 CBN wheel and honing with 2-3 passes on the leather wheel with 3- micron diamonds we were getting the same sharpness.

DATA

All knives are sharpened at an edge angle of 12 dps, to initial sharpness near 100 BESS.

Link to raw data >>

[Image: Key_Indicators1.png]

3% VANADIUM PHENOMEN

“Curiouser and curiouser!” as said Alice in Wonderland.

Numbers tell us that edge rolling does depend on whether we sharpen with aluminium oxide or CBN/diamond, and CBN/diamond gives better lasting sharpness than aluminium oxide, but correlation with the vanadium content is not linear – instead, there is a dramatic rolling in edges with vanadium content of 3% sharpened with aluminium oxide.

DATA INTERPRETATION AND CONCLUSION

Control 0% vanadium (SR-101) – the control test shows some improvement in edge resistance to rolling when CBN/diamond abrasives are used, which is interesting in itself, however the main thing it gives us for the purpose of this research is the baseline difference between the CBN/diamond and aluminium oxide abrasives, so that any numbers less-than-or-equal-to are not related to alloys composition.

Vanadium 1% (D2) - CBN/diamond abrasives moderately improve sharpness over aluminium oxide, with no difference in the initial period.

Vanadium 2% (PGK) - CBN/diamond abrasives have little to no advantage over aluminium oxide, seen only in somewhat prolonged edge life; initially the edge sharpened on aluminium oxide shows even better elasticity and sharpness (Phase I).

Vanadium 3% (Elmax) - CBN/diamond abrasives show high advantage over aluminium oxide, the edge stays sharp by 4 times longer. In saying so we are talking of relative difference, and positive effect of the CBN/diamond as such is not that much different from its neighbours of 2% and 4% vanadium (as seen by the absolute sharpness scores) – it is the aluminium oxide worsened edge retention that makes the numbers so high.

Vanadium 4% (CPM20CV or M390) - CBN/diamond abrasives have moderate advantage over aluminium oxide, clearly noticeable both in the initial period and prolonged life of the edge.

Vanadium 9.8% (Vanadis 10) - CBN/diamond abrasives have moderate to high advantage over aluminium oxide, the working edge lasts 1.5 times longer.

3% vanadium is the threshold content, where sharpening with CBN/diamond becomes preferred over common abrasives.

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  What is proper sharpness?
Posted by: SHARPCO - 05-13-2018, 01:40 AM - Forum: All About Edges - Replies (10)

I believe that whatever is appropriate is the best.

What about the sharpness of the knife?
DE razor sharp blade is the best?(50 BESS)
What is the most ideal BESS value you think?

Of course, this will depend on which knife is used for what purpose.

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  EDGE RETENTION/ROLLING PART II
Posted by: EOU - 05-09-2018, 10:13 AM - Forum: Edge Sharpness Testing - Replies (28)

This thread is a continuation of Edge Retention/Rolling Test Stand.

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