Sharpening high hardness and wear resistant steels

[Steel_Drake]

Is there a preferred angle for this steel? This more of a comparison rather than a steel performance test, so as long as all other factors are apples to apples I'm not thinking a lot of thought needs to go into the specifics
I was planning on 28-30° with no microbevel and stropped only on paper to reveal any burring.

I would assume ~15 dps with no micro should be fine, at least unless you notice excessive microscopic apex chipping in your tests.

All edges get tested with dynamic load pressure cut, average of three cuts.

Then draw cut test starting with 7lbs and working up by lbs to a load that reliably cuts three in a row.

If the numbers are comparable*, I go back and hit each media a second time, verifying the initial pressure cut number, then draw to failure on three in a row, with identical static load.

If the initial pressure cut number is not within 15% > the original number, I resharpen and then retest. If it lower than the original, I keep the lower number, retest for the lowest static draw load to three cuts and then proceed with the retention test.

* If the numbers are not comparable the test stops there. I resharpen to verify any trend - if it still exists, the test is over - no retention phase.

This sounds like a reasonable plan to me.

Further speculation:
what if one of the edges is consistently higher on pressure cut and lower on draw cut

- tentative conclusion might be that it is creating a more coarse scratch pattern.

Likewise if one is consistently lower on the pressure cut and higher on the draw

- tentative conclusion is a finer scratch pattern.

I will be interested to see the relative pressure cut numbers, particularly for the Spyderco stones to see how it relates to my own Spyderco M and DMT EEF.

Only if one of the samples is better on both modes would I tentatively claim a better abrasive outcome.

I would expect both the Spyderco and DMT apexes to outperform the King apex on both tests, given that the King 4k is inherently going to produce some apex rounding.

Continuing issues to be considered - if the beginning values for pressure cut are off by more than about 15% (eg 20lb to 23 lbs) of each other, I would fully expect the draw cut retention to be biased in favor of the pressure cut edge that had the most resistance/highest amount of inherent friction. We'll have some numbers either way.

Do you happen to have a Spyderco UF? At the very least, if your lapped Spyderco F produces a pressure cut result too much lower than the DMT EEF, you could always try your Spyderco M using very low force and see if that gets you a more comparable starting number on the pressure cut test. The King 4k is probably going to be worse to start on both, so I don't know if you will need to worry to much about equalizing that one.

 

[Steel_Drake]

A question in different perspective - Won't VC wear Spyderco M AlO?

Probably, but I'm not planning to scatter a bunch of 1500 git VC on my Spyderco M, either

do we get the same cutting speed at 3k? also how is the finish? do these stones have the feel of the norton crystolons?

The SPS-II 240 has a similar feeling to a Crystolon, the 1000 less so, and the stones above 1000 just feel like weak bond waterstones. As for cutting speed, I will just say this: SiC is faster cutting than AlOx generally, and SPS-II stones have virtually zero binder in them, meaning the abrasive density is higher than other waterstones and that they expose fresh abrasive very rapidly, even when used with low force.

Sounds like, and correct me if im wrong, but after say the 400 grit, i need to go to cbn or diamond paste/spray to avoid burnishing or tearing out carbides.

So, to be honest, the best answer we have right now based on empirical research is "maybe."

The conventional wisdom is that you should switch to diamond or CBN above ~1000 grit, but my own empirical testing found that I got comparable results from using AlOx or SiC abrasives to using diamond plates no matter how high I went in grit.

One key point to consider, though, is that I use very weak bond waterstones and use them very muddy, and that isn't really a practical option on an Edge Pro, and as far as I know, Naniwa Choseras are fairly strong bond waterstones that don't shed grit very easily, plus guided systems are also slower than using a benchstone freehand.

Based on all of these factors, I would probably say that you may want to consider getting the DMT stones for your EP for high vanadium content steels, but unless you had some particular reason you wanted an apex finish above ~4000 grit, I wouldn't bother with any strops.

 

[BluntCut MetalWorks]

A sort of OT but I will stick/stash my new video here

A reminder for my future self, however open/share to public... It is in rambling mode, hence patience & humor are required to watch/endure this 25 minutes video

[video=youtube_share;cfoEOLwOMGQ]http://youtu.be/cfoEOLwOMGQ[/video]

 

[BluntCut MetalWorks]

When I use EP for high cv steels, stock 320 produces good working edge. 600 (10um) mostly polish some more but less durable edge. So, with Chosera (assuming high abrasive density - from what I heard), 1K (~12-14um alumina) would be a ok finest non-dia/cbn stones. Ideally 600-800grit chosera probably still in excellent zone for plowing/profiling (low burnishing %) the bevel.

My fancy 1K waterstone even struggles with 65rc D2 (it has about 0.75%V), so consideration should be for combination of cv & hardness. For same pressure amt, hardness limits depth of cut, so burnish will kick in sooner.

Ive read through this, and im probably more than ignorant to alot of the metallurgical jargon. The knowledge you all have is staggering.

I currently have an edge pro, with the chosera set from chefknives to go. Chosera 400, 1k, 3k , 5k and 10k.

Sounds like, and correct me if im wrong, but after say the 400 grit, i need to go to cbn or diamond paste/spray to avoid burnishing or tearing out carbides. Its counterproductive to go through my usual grit progression with m4 or s110v. I dont want to spend time on unnecessary steps, or doing something that degrades my edge.

Should i put money into strops and pastes, or get dmt 2x6 to use in my edge pro.

Im profecient with the edge pro, and thought i had sharpening steel down, but i see there is another level of sharp I'd like to get to.

 

[Wowbagger]

One key point to consider, though, is that I use very weak bond waterstones and use them very muddy, and that isn't really a practical option on an Edge Pro, and as far as I know, Naniwa Choseras are fairly strong bond waterstones that don't shed grit very easily, plus guided systems are also slower than using a benchstone freehand.

The Jende 120 stone for Edge Pro, basically a Shapton, tends to get weak bonded and very loose (don't know if I would call such a coarse stone that is white "muddy"). It was much less so when new. Then I put it away wet in a Tupaware box with other damp stones, not submerged / no water other than what had soaked into the stones in use. The next day or maybe two days later I took it out and used it again and it was pretty different . . . loosing grit much more readily. Personally I hate that; I don't want to wear it out quick so I leave it out by its self to dry as much as possible between uses.

Anway I thought I would put that out there for whom ever might benefit from it. The wider stone in the photo is a Shapton 220. It works great for me but it doesn't have the same characteristics as the Jende 120.

 

[Wowbagger]

patience & humor are required

Bluntcut,

I find that to be the best approach to life in general.
Thank you SO MUCH for the video. I am looking forward to it.

 

[Wowbagger]

PS: First off that thin knife is what I like. I agree. Can do a lot / most things with such a knife.

And steering. Yes I think that was a lot of my trouble with my limited experience with S110V, one blade, my main test is trimming hard rubber. Apparently, from what I gather from your video, there is side loading force from the solid block of rubber and the apex is flexed to the side where the thin curl is coming off and the edge, which had a relatively thick blade (0.030 inch behind the edge ) and ~15°per side could not accommodate the flexure without apex damage. It did feel like super fine chipping . . . or as I called it in the past posts "felt like the carbides fell out of the matrix".

My ZDP-189 can take it in stride though and perform better.
?? ? ?
My M390 with a thinner blade behind the edge has no problem with the task and cuts for ever. Well many, many, many cuts for the M390 as opposed to one or two cuts and is dead which is what the S110V did.

Interesting the info that the more the edge is refined the more chance the steering can cause damage due to errors in edge geometry . . . I am pretty sure that is right. Is that what you were saying about refining the edge and that the initial coarse apexing was going to be about as good as the cut was going to ever be? That is what Ankerson seems to be going with as well.

I am eating this stuff up. Please . . . I am bowing as I say it . . . if I may . . . with respect . . . be so bold as to suggest that you make a list of things you wish to talk about before the video (talking points) so that we do not miss out on anything.
Thank you,
THANK YOU !

 

[BluntCut MetalWorks]

Wowbagger - thanks much for good words + plenty of patience + suggestion.

I decided to shoot the video while I was chillaxing in 58F ocean water - coherent thoughts disappeared by the time I thawed ...

 

[Chris "Anagarika"]

Luong,

The thin paring reminds me of certain AEBL paring .
So basically you're saying having the thinnest apex isn't always the best. A stronger geometry that still cuts will perform much longer because the apex area has more support, i.e. 3 micron apex might last longer than 0.5 micron one (not abrasive finish, the actual apex width/thickness/diameter if you will).

This echoes with most experienced sharpener that hair whittling edge won't last and Jason's advice to finish DMT C and the1 micron strop for general use.

Much to ponder upon. This thread with the ideas exchanged with much respect to each other should perhaps be a sticky.
Thank you (to everyone too that contributed to the discussion & testing).

 

[ice-pic]

Hi Luong
Thanks for the video with your thoughts.
I like to do a sawing motion when using knives if possible,this always helps me.The 10v does have
that "toothy" feel to it that lots of people notice.
I find most of the damage my knives incur is from slaming into the cutting board as the knife breaks out the other side of what I am cutting.
Sawing motion reduces this since it is easer to slow down just befor the blade breaks through.Also and this is hard to control is during food prep
things can get hectic and a knife laying on a cutting board can easly get bumpted into another knife,a glass or any number of hard objects and those fast smacks into
immovable objects spell instant chip,or microchip.
I need to watch the video one more time before I comment further.Kind of rambleing a little myself
Jay

 

[HeavyHanded]

I try to cut on my board at an angle so the apex isn't hitting dead on, seems to help with longevity.

The 10v blank I sharpened up on DMT coarse at 15°/side and stropped hard on a Washboard with the diamond/SiC honing compound, then a handful of light passes. Crazy sharp but still very catchy, was treetopping leghairs 1/2" above the skin in large quantities, liberating 1/8" wide strips dead across the grain on newsprint.

This be some good steel...

 

[Wowbagger]

I like to do a sawing motion when using knives if possible,this always helps me.The 10v does have
that "toothy" feel to it that lots of people notice.
I find most of the damage my knives incur is from slaming into the cutting board as the knife breaks out the other side of what I am cutting.
Sawing motion reduces this since it is easer to slow down just befor the blade breaks through.Also and this is hard to control is during food prep
things can get hectic and a knife laying on a cutting board can easly get bumpted into another knife,a glass or any number of hard objects and those fast smacks into
immovable objects spell instant chip,or microchip.

See that is where I get screwed up . . . or I'm screwed up . . . I have a great deal of use for push cutting. Where I trim rubber it is easy to over shoot and slam into the machine not only damaging the knife edge but the finish of the machine or damaging expensive parts. I tend to grip the knife like a carver. No chance of over shooting but a push cut must be done because there is little room for a sawing motion.

That and I just don't feel like a blade is sharp if it won't push cut like a magic wand. When I want to saw I grab a saw. As far as "slamming into a cutting board" I rock the knife on the belly so the edge is in contact with the cutting board before it leaves the work / food.

Bumping into another knife or a glass. AAAAAYAH ! Simply . . . DO NOT DO THAT . . . it is going to damage the edge.

signed : hopelessly addicted to polished push cutting edges. My Dad once told me "Kid . . . the day I have to ride a bicycle to work is the day I quit working". I ride a bicycle to work everyday to do my part to protect the planet's atmosphere . . .
but . . .
the day I have to use only rough toothy edges is the day I find another hobby.

Diamonds and stropping . . . I'm gesturing like I am poking my finger down my throat like a little school girl . . . now I'm switching to valley girl voice : "I mean gag me with a spoon !"
[video=youtube;sTKPxu55lXs]https://www.youtube.com/watch?v=sTKPxu55lXs[/video]

 

[Wowbagger]

This be some good steel...

aaaaaaah not quite so fast . . . I want to know how it does trimming slivers off hard rubber. My 110v could cut hair, whittle hair, catch on hair. Petered out in the real world.

Vid trimming hard rubber or it didn't happen.

 

[HeavyHanded]

aaaaaaah not quite so fast . . . I want to know how it does trimming slivers off hard rubber. My 110v could cut hair, whittle hair, catch on hair. Petered out in the real world.

Vid trimming hard rubber or it didn't happen.

Game on!

 

[ice-pic]

In defense of me?? I must say I haven`t always been like this,it is something I have just started to realize.
My blades stay sharp longer if I can use a reciprocating action when using a knife.This is not always practical I know but it takes practice.
I do not cut much rubber.

 

[Wowbagger]

My blades stay sharp longer if I can use a reciprocating action

Yes I think Ankerson proved that beyond a shadow of doubt.
The Chef just told me she saw Jacques Pepin cutting stuff and dropping onto the cutting board and there are times when ONE MUST DO THIS. She said he was cutting potatoes.

I can cut potatoes without all this knocking of my edges.
But . . . I'm no Jacques Pepin
and no The Chef for that matter.

Sigh . . . I suck.

 

[ice-pic]

I have a 1/16" Teflon sheet I use sometimes over cutting board,I am planning to make a thicker one but they are costly,
and I am not sure they work.

 

[BluntCut MetalWorks]

To be clear - on what I was conveying in video.

Apex thickness/radius is the shoulder width of the intersection between 2 planes (aka cutting bevel). It doesn't matter whether this is a flat top or rounded or 50dps nano/2um bevel - envision this a perfect geometric shape.

Teeth/jaggedness & surrounding the cutting edge are just complex geometry, which (if you like) could map into a multi-level apex thicknesses. Nano peak points = sparse apex level 0; level1=ledges of teeth; levelN = trough/teeth-base. Easy to see level0 needle/scallop points with nano thickness will damage quickly. This is a case where extra complexity is just bogdown factor of low value.

Project cutting dynamic to hydrodynamic. If the bow of the ship allows low torqe side-2-side flex, will steer this ship in circle. Super thrust will break the bow.

** Edge Performance Optimization **
Geometry that support tasks and techniques that yield best result.

Using skillful techniques to get best result is a bonus. Babying/timid usages to get result = something is wrong with either the blade and or user. So if impacts are part of usage, use geometry that supports impact -> if steel forced inefficient geometry, lol yeah - use a better (in context of intended tasks) steel if avail.

** benchmark **
biases on too thin/thick/jagged; low/high edge shaping skills; forces amt/vector; validation; etc... So on.

 

[ice-pic]

If I may;
** Edge Performance Optimization **
Geometry that support tasks and techniques that yield best result

Means to me bevel angle should be chosen for task at hand.Such as 30dps for Axe,and 15dps for parer knife.

** benchmark **
biases on too thin/thick/jagged; low/high edge shaping skills; forces amt/vector; validation; etc... So on.

Means to me not sure here but too thin a knife with jagged edge or curled edge will direct cutting force vector to destructive direction.

 

[BluntCut MetalWorks]

Chris,

Yeah - yours aebl paring is very thin as well (I can't recall in my mind now - lol).

For aebl paring thinnest apex where degradation is by wear, could be 1-2um wide. Of course depend on tasks & technique & pressure, etc..

General DMT C + 1um strop probably produces toothy edge - so longevity hinge on factors ^ above. Sub micron peaks could degrade rapidly and if failure mode is roll/deformation, performance could drop quicker than intended. Having a gut feeling (hahaha by empirical experience) what thinnest apex be - could aim for ideal strop rounding the apex, to ensure edge is no longer in damaging range - i.e. in wear mode. Jason B's has more sharpening experience than I, so producing these kind of edges are probably just an inherent instinct to him :thumbup:

Luong,

The thin paring reminds me of certain AEBL paring .
So basically you're saying having the thinnest apex isn't always the best. A stronger geometry that still cuts will perform much longer because the apex area has more support, i.e. 3 micron apex might last longer than 0.5 micron one (not abrasive finish, the actual apex width/thickness/diameter if you will).

This echoes with most experienced sharpener that hair whittling edge won't last and Jason's advice to finish DMT C and the1 micron strop for general use.

Much to ponder upon. This thread with the ideas exchanged with much respect to each other should perhaps be a sticky.
Thank you (to everyone too that contributed to the discussion & testing).