Edge-leading chipping...ouch!!

[1315]

So I'm newer, and have a White #2 bunka that I chose to practice with. It was delightfully sharp, but I wanted to compare edges left by a Shapton Glass 4K vs a Belgian Blue.

With the Glass 4K: Since already sharp, I started with 15 edge leading strokes, then tapered off pressure to 10, 8, 4, then a few light finishing strokes. I had been using the magic marker trick to judge angle, but recently read about slightly increasing angle through the progression, so I wanted to try it. Very nice edge, and pretty when scanned under my cheap microscope, but but noticed it was kinda loud on paper.

So I sprayed the BB with some water and ran the same progression. Sounded good on the stone, but got caught up on paper. Uh-ohhh. Took a look, and I chipped the heck out of it on the BB. the Glass didn't do this? I think I ran the same angle on both stones, but for some reason, the BB really bit harder. Maybe I increased angle too much...maybe the edge was too refined and the BB bit into it more (it didn't do this on the prior Blue #1) ...I gotta figure this one out!

 

[M1k3]

Did you round the edges of the stone?

 

[deltaplex]

Was the 15-10-8-4-no pressure strokes to finish per side, per stone?

 

[HumbleHomeCook]

I say don't count strokes but that's just me.

What was your intent with altering the angle as you went on a finishing stone? Just trying to understand.

SG4k and BBW will still remove metal so perhaps the edge was overly thin?

 

[Ruso]

Was the 15-10-8-4-no pressure strokes to finish per side, per stone?

You are doing it wrong, the progression is not power of two.

 

[Benuser]

I say don't count strokes but that's just me.

What was your intent with altering the angle as you went on a finishing stone? Just trying to understand.

SG4k and BBW will still remove metal so perhaps the edge was overly thin?

How about the pressure you were applying? I do see more damage than the chipping. Not sure it was completely deburred before the intended refining.

 

[Barmoley]

How about the pressure you were applying? I do see more damage than the chipping. Not sure it was completely deburred before the intended refining.

That's what I was thinking. Looks like there was a burr that was damaged on BB. Hard to say though, but sounds and looks like it.

 

[Rangen]

I once trashed an edge in a very hard steel knife by using way too much pressure. It didn't look like this, though; it looked torn up. Never saw chipping like that, with so many neat straight lines.

 

[1315]

Wow, thanks for contributing to solve my dilemma. Great ideas.


Did you round the edges of the stone?
-Yep, new stone, but chamfered and smoothed out with the bout that came with it. Also, the Blue #1
sharpened before it didn't chip.

Was the 15-10-8-4-no pressure strokes to finish per side, per stone?
-Yep, per side per stone. Knife was already thinned and sharp, so pressure was about half of what I normally
apply.

What was your intent with altering the angle...
- Was a tip from another sharpening thread, from Kip I think...thought I'd try it. Also, after printing a 15-degree angle on
cardboard, and using it to confirm correct blade angle, I was sharpening at too shallow an angle, so I lifted it to closet to 15, AND tried a slightly increased angle on the progression.

You are doing it wrong...
- You sound like my wife.

Not completely deburred.
- Very possible. I stropped on newspaper with pretty firm pressure, then I dragged it through a large pink eraser, then wine cork. I know deburring on a stone is the preferred method, and I do that, but not with confidence. I seldom see burr, but it does seem most discussions like this always come back to perfecting burr removal.

 

[Stockman]

I would suggest that you make 5 or 6 passes, medium pressure, edge trailing ( not leading ) on one side only and then feel for a burr on the opposite side.
If you feel a burr, then that would confirm that it is only small sections of the burr that have been removed giving the appearance of a damaged edge.

 

[Matt Jacobs]

It sounds like to much pressure to me

 

[Rangen]

I'm wondering whether the eraser and/or wine cork tore off your burr in a particularly bad way. I gave up on those "grab the burr and tear it off" methods long ago, because I got some results I didn't like. That doesn't mean your only other choice is the stones. Strops are another. Abrading a burr away with a nice diamond-pasted strop is a much cleaner method than tearing off the burr. I usually use the stones, but every now and then, a strop is just the thing.

 

[Benuser]

If I want to achieve a micro-convexing I do so with a very light touch on a stone in the 2k range, making sure to have previously completely deburred the edge. Not willing to integrate burr remnants into the new edge. You may further polish afterwards. Use a loupe.

 

[timebard]

When I got my BB I also initially just smoothed the surface with the small slurry stone, however I noticed some inconsistent feeling spots in the surface and wasn't super happy with the results. Using an Atoma to get a more flattened and uniform start, and then using the slurry stone to refine a bit, seemed to help. YMMV though.

 

[natto]

Very possible. I stropped on newspaper with pretty firm pressure, then I dragged it through a large pink eraser, then wine cork.

This might explain the shape of the damage. An edge ground too thin will fail with the first use. Stropping a thin edge with pressure causes heavy flex. And the cork grabbed damaged spots and tore off this funny triangles.

How thin is that edge and how is the flex test?

 

[D J]

Have you tried marking your finger after finding the edge "angle" to keep the consistency