Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Wire Edge Prevention
#21
Smile 
(09-14-2018, 03:36 AM)Ken S Wrote: KG,

Someday your last sentence will read, “We had to invent a test for them”.

Impressive work.

Ken

Ken, the cohort of 50-60 year old youngsters on this forum lack the manners and humour of your generation  Blush
http://knifeGrinders.com.au
Reply
#22
KG,

That's the problem when the exchange opened membership to those 50-60 year old youngsters! Smile

Ken
Reply
#23
In the beginning of the SET development, Mike experimented with perpendicular load on the edge.
Here are excerpts from the page 4 to 6 of the post Edge Retention/Rolling Test Stand http://www.bessex.com/forum/showthread.p...240&page=4

FLAT IMPACTOR (flat end of a steel rod)
2140 grams = about 4.7 lbs load on a hardened 5/16" steel rod did not effect the burr-free edge of a mid-range Henkel chef's knife - the same BESS reading of 160 BESS and unchanged optical microscopy.

[Image: Test_Stand_Weight.JPG]

RADIUS IMPACTOR (round of a steel rod)
"If you recall, in our earlier test with the 5/16" rod end this amount of weight didn't affect the edge. With only the radius of the 1" diameter rod contacting the edge now, it did and substantially so..." - seen both on the sharpness tester (from 150 BESS to 700) and under x140 magnification.

[Image: test_stand_load.jpg]

FURTHER TESTS with the rod
1000 grams load rolled the edge of 150 BESS by 325 points (measured 475 BESS). "Once again we can see the rolled edge at 140X."

Steve, the Mike's flat impactor tells us that a load of 2+ kg (4.7 lbs) on your brass plate is absolutely safe for a burr-free edge.
The question remains whether we can detect wire edge on the plate, or have to use some sort of radius impactor.
The above flat impact is similar to your plate, and the radius impact can be done on a pipe or rod placed horizontally. Copper, brass and lead or soldering tin are readily available in plates, pipes and rods and should be safe for the de-burred edge. I will have time for testing tomorrow, and you please keep us posted on your findings.

I will also test the PEX plastic pipe, used in deburring stubborn burrs on mainstream s/s knives. For those new to this technique, you scrub the edge perpendicular to the length of the PEX pipe - first in one direction, and hone the opposite side of the edge, then in the other direction and hone the other side of the edge.
Last year I tried the PEX plastic pipe as an aid in deburring high-end knives with no success, but it still may be useful for detecting the wire edge.
http://knifeGrinders.com.au
Reply
#24
I had forgotten about the flat impactor tests, thanks for pointing that out. That was using significantly more pressure over a smaller area than what I've been doing, so my puny tests are probably not of much interest. But, I did some testing on S90V today, and am listing the results here. About the only conclusion I can draw from them is that I either need to get better control of my testing procedure or leave it to pros like you.

For each BESS sampling, I did 5 tests, all near the same point on the blade (straight, non-bellied portion).

Test #1:
Sharpened on Wicked Edge at 20dps, progression: 800, 1000, 1500 diamond, then medium, fine ceramic. Total sharpening time as about 5 minutes. Followed by brass-plate pressuring at 2~4 pounds (estimated).
BESS: 151, 263, 178, 210, 222
* It was a quick sharpening, but I wasn't expecting a burr - the readings indicate that I probably had one.

Test #2:
Back to the WE, just did 1500, medium, fine, then followed by 30 edge-trailing medium-pressure passes on one side only with the medium ceramic to force a burr, followed by the brass plate pressure.
BESS: 262, 242, 259, 172, 227.

Test #3:
Resharpened same as test #2.
BESS: 124, 199, 158, 143, 147

Test #4:
Stropped on wood-mounted leather coated with Chromium Oxide, alternating sides.
BESS: 106, 111, 126, 90, 85

Test #5:
Applied brass plate pressure.
BESS: 113, 104, 92, 102, 118

Test #6:
Getting frustrated with the brass plate, I raised it a notch by slice-cutting on the corner with fairly low pressure.
BESS: 116, 90, 107, 124, 69

Test #7:
Since the strop can better the BESS readings, I figure it can also create a burr. So, I stropped with heavy pressure one side of the knife 30 passes on the CrOx strop.
BESS: 117, 119, 84, 114, 107

Test #8:
Applied brass-plate pressure as before.
BESS: 141, 108, 110, 128, 104

Test #9:
Did a brass-plate draw-cut, as before.
BESS: 131, 137, 121, 122, 142

Not really tests, but for completeness...
Then I restropped on CrOx, BESS: 110, 97, 116, 100, 109
Then I broke down a small cardboard box, BESS: 127, 146, 125, 180, 115

FWIW, I should probably do a similar test on a different steel; for me S90V is a steel that never gets dull, but also never gets sharp. I think S30V would have been a smarter choice to start with, but frankly I'm at a loss in understanding what's happening here. My guess is that operator error is having the largest influence.

I'll be very interested in hearing how you fare with your experiments, plastic might have the right properties for this.
Reply
#25
Knowledge of what does not work is as important and difficult to get as the positive.
Thanks to your tests, we can forget the plates and move to testing the pipe/rod that should show clearer the difference between the burr and a clean apex by reducing the contact area and increasing the load per point.

Funnily enough I was also thinking of S90V or S110V to begin with, but following your tests... you are right, ELMAX or S30V should be a better start.
http://knifeGrinders.com.au
Reply
#26
Yeah, agreed - just not nearly as much fun.

I'll run a shorter series of tests tomorrow and post the results. I think I'll put a brass sleeve over a dowel so it can roll and draw the blade over that. I just pulled out an S35VN Native5 for this, and I'm planning on measuring 1) Freshly sharpened, 2) With a stropped burr (hopefully) applied, and 3) After drawing across the brass sleeve. If there's anything you'd like me to add to that, let me know.
Reply
#27
Interesting stuff Mr. Steve. Do you see advantages to this method over optical microscopic observation of the edge?
Reply
#28
(09-14-2018, 11:16 PM)grepper Wrote: Interesting stuff Mr. Steve.  Do you see advantages to this method over optical microscopic observation of the edge?

Yeah, for me at least - I believe that my edges aren't lasting as long as they should, but I don't see any burr, even at 200x magnification, so between that and the fact that my BESS readings vary quite a bit over the length of the blade, I think I might be leaving some burr on the edge.  If that theory is correct, then my efforts to deburr aren't working, or are creating a burr themselves.  It could just be my lack of microscope skills (or my vision, which isn't great), but I'm looking for something a little more foolproof (and for me, quicker - like an idiot light instead of a gauge).  So, when I read KG's post about the pressure of the BESS media crushing the burr and affecting the reading on soft steel, it really caught my attention.  Maybe I should just start using soft steel...
Reply
#29
I ran my tests this morning, here are the results:

S30V Native 5 Sharpened at 15dps on Wicked Edge

Sharpened Stropped Burred Rolled Burred2 Rolled2
Sample #1 84 81 117 122 129 127
Sample #2 130 118 108 139 94 135
Sample #3 113 121 127 121 129 168
Sample #4 87 98 121 139 127 153
Sample #5 101 126 124 131 154 141
Mean 103 108.8 119.4 130.4 126.6 144.8
Std Dev 17.0 16.8 6.6 7.8 19.1 14.4

Notes:
Sharpened = Straight off the WE, progression 600, 800, 1000, 1500 Dia, Med, Fine Ceramic, 14, 7, 5, 3.5, 1, .5 micron diamond paste on balsa strops.
Stropped = 30 alternating-sides freehand passes on CrOx on leather.
Burred = 50 one-side-only heavy pressure passes on CrOx leather.
Rolled = 5 passes approx 1lb pressure on free-rolling 1/4" brass sleeve (cylinder)
Burred2 = 30 medium-pressure passes on 5 micron diamond paste on leather on WE - same angle as sharpening angle.
Rolled2 = Rolled

Notes:

- I think I must not be hitting the apex on some of my steps (though I raise a detectable burr with all of the stones), overall even my sharpening results were disappointing.
- The Burred2 was visible under 200x magnification (so to your point Mr. Grepper, I don't see advantages at this stage of my knowledge).
Reply
#30
Shoot, I spent time aligning all of those columns, and they "de-aligned" once posted. Sorry.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)