Sharpening high hardness and wear resistant steels

[Wowbagger]

they sharpen anything.

that's what grabbed me

They have a much better feel than a regular diamond plate

The feel of diamond plates and the smattering of oversize grit here and there is what keeps me away from the plethora of diamond plates that I already have. That said I was using a little one last night but just to sharpen a "carbide" box knife blade. The lumps of grit and the progression makes me do the rabbit in the head lights stare . . . I mean 1200 and then the next step up is 8000 . . . ohhhhhhhhh K.


I'm referring to the little plates in this set. I was just free handing with them.



you can see all the little ones I have in this photo



I was sharpening this thing (the one that says "carbide" on it.
I might like some real stones with diamond as part of the make up if it was a significant volume of diamond.

 

[Steel_Drake]

The maxamet mule finally arrived, and while I haven't yet had time to get into any detailed testing, I do have a few comments to share that may be relevant to this thread:

1) Those suggesting that maxamet would be more difficult to sharpen than a ceramic knife were totally incorrect. The maxamet mule takes, at the absolute most, twice as long to apex on the SPS-II 1000 than my knives in CPM-M4 do, whereas the ceramic knife took at least 6 times as long to apex on the same stone.

2) A quick check on how effective AlOx is at grinding maxamet at all:

These first two images show the scratch pattern left by a SPS-II 240 on the edge bevel:




And this is the scratch pattern left by a King 1000 with ~100 pps starting from the above:




And this is the scratch pattern left by a King 1000 with ~200 pps total after the SPS-II 240:




I think images show pretty clearly that a King 1000 can and will grind maxamet, and furthermore that the number of passes required to make the 240 -> 1000 grit jump is not qualitatively different from the number that would be required on CPM-M4.

I will also note that (after deburring) I was able to obtain an apex off the King 1000 that would easily slice newsprint, pushcut it with the grain, and which had some ability to do crossgrain pushcuts. This would appear to be pretty compelling evidence that a King 1000 is capable of grinding maxamet and capable of getting a good quality apex on it.

Of course, none of that speaks to the specific proposition I'm planning to test, but it certainly is interesting. It will be at least a few weeks before I can shoot and edit the video required to compare the behavior of edges on the maxamet mule finished on a King 4000, SPS-II 3000 and DMT EEF.

 

[ice-pic]

Lots to digest here let alone understand.
I just reserected my old dissecting B&L stero microscope.
!0x eyepieces and 1.3,3,and 7.5 objectives.That gives me 750 times magnifaction and a real good look at the edgeds on my knives.
Can`t take pictures or measure yet but I have started to look at my 10v knife every day after using in the kitchen and looking for changes
or nicks or other wear patterns.
Not really trying to find anything just looking.
I really likt this 10v 68hrc .

 

[BluntCut MetalWorks]

OK, I stack pics of maxamet & m4 edge after King1K. In spite of resolution/magnification between pics, it's quite obvious maxamet carbide haze is dense & thicker and edge is more serrated/toothier.

The maxamet mule finally arrived...


M4

...

Ice - Thanks and glad your eyes aren't super-man, otherwise 10v edge would disintegrate by xray staring

 

[ice-pic]

LOL I try not to stare.
I was wrong on my magnification calculation 7.5 times 10 equal 75 times mag.
No Xrays there.

 

[Steel_Drake]

OK, I stack pics of maxamet & m4 edge after King1K. In spite of resolution/magnification between pics, it's quite obvious maxamet carbide haze is dense & thicker and edge is more serrated/toothier.

Luong,

The blade in CPM-M4 had not been sharpened on an Atoma 140 and SPS-II 240 immediately prior to the King 1000, unlike the Maxamet mule, so I don't think it is particularly surprising that the scratch patterns of those much coarser stones wasn't fully removed yet.

Just to double check that, I will resharpen the Maxamet mule later today on the King 1000 to get some images of the scratch pattern left by the King 1000 starting on the same basis as the CPM-M4 blade pictured above. In any case, the question was not whether it would take longer to sharpen Maxamet on a King 1000 than CPM-M4, but rather whether a King 1000 would grind Maxamet at all, as I have in the past seen people contend that a King 1000 won't work at all on such a steel.

 

[BluntCut MetalWorks]

Most magnification devices often state mag in area rather than linear, so 100x area = sqrt = 10x linear.

LOL I try not to stare.
I was wrong on my magnification calculation 7.5 times 10 equal 75 times mag.
No Xrays there.

 

[BluntCut MetalWorks]

SD - thanks for doing all this tests & shared results :thumbup:

Try sharpen maxamet on king stone under running water (that's right, don't let it mud up to prevent lapping process to under cut the footing of carbides on surface). I can scratch 10V surface with sand, so it's feasible to sharpen with sand but impractical + very far from optimal result. I agree, king stone will yield result somewhere in between. otoh, quite a few posts above stated diamond abrasive produces better result. Furthermore, water jet will cut hardened 10V/maxament and even 95% solid block of tungsten carbide, well feed rate will be extremely low and grit consumption will be very high - because cutting relies on remove enough binder/matrix so impact can knock carbides away.

I've a king6K (very hard stone) - with 10v, it will glaze over in a few passes. When explicitly scrap up with mud, it will do some polishes in gap between carbides.

Luong,

The blade in CPM-M4 had not been sharpened on an Atoma 140 and SPS-II 240 immediately prior to the King 1000, unlike the Maxamet mule, so I don't think it is particularly surprising that the scratch patterns of those much coarser stones wasn't fully removed yet.

Just to double check that, I will resharpen the Maxamet mule later today on the King 1000 to get some images of the scratch pattern left by the King 1000 starting on the same basis as the CPM-M4 blade pictured above. In any case, the question was not whether it would take longer to sharpen Maxamet on a King 1000 than CPM-M4, but rather whether a King 1000 would grind Maxamet at all, as I have in the past seen people contend that a King 1000 won't work at all on such a steel.

 

[Chris "Anagarika"]

Most magnification devices often state mag in area rather than linear, so 100x area = sqrt = 10x linear.

Thanks Luong, I didn't know that. Thought the madnification is linear rather than area ... Learn something new!

 

[Steel_Drake]

SD - thanks for doing all this tests & shared results :thumbup:

No problem. My focus is on learning and in order to learn it is necessary to experiment and share the results.

On that note, here is a couple of microscope images of the Maxamet Mule sharpened on a King 1000 when not starting from a much coarser scratch pattern:




One of the surprising things I've noticed with this mule so far is that it seems to take a much higher push-cutting sharpness off a ~1000 grit stone than I'm used to. I'm not sure if this is the result of the very high hardness of the blade, or because I'm using a wider edge bevel angle than I unusually do.

Try sharpen maxamet on king stone under running water (that's right, don't let it mud up to prevent lapping process to under cut the footing of carbides on surface).

Do you mean that the King 1000 will not be able to work on Maxamet if you don't use it muddy? I always use all my waterstones muddy, I actually flatten them with an Atoma 140 immediately prior to each use to pre-generate a mud on them.

it's feasible to sharpen with sand but impractical + very far from optimal result. I agree, king stone will yield result somewhere in between.

Whether and how far from optimal the apex produced on AlOx or SiC waterstone is vs. diamond is exactly what I will be testing. So far, I haven't seen any obvious issues with using AlOx, SiC or diamond at 1000 grit but the real test will be in the JIS ~4000 range.

I've a king6K (very hard stone) - with 10v, it will glaze over in a few passes. When explicitly scrap up with mud, it will do some polishes in gap between carbides.

I've never used a King 6000. I do have a King 4000 (which is also fairly hard) that I will be using for the test, but in general I prefer the SPS-II 3000 or Naniwa Aotoshi 2000 to the King 4000 as I prefer extremely muddy waterstones.

 

[Wowbagger]

I prefer extremely muddy waterstones.

Why ?

I'm the opposite . . . I immediately wash off any build up. In my sharpening world the nagura is for "erasing" metal swarf out of the pores of the stone. Only.

What advantage do you find from the slurry ? I have always wondered what the attraction was other than some intermediate polishing between stones but seems to slow down actual cutting of the blade material to produce an edge as fast as possible.

thanks

 

[Steel_Drake]

Why ?

I'm the opposite . . . I immediately wash off any build up. In my sharpening world the nagura is for "erasing" metal swarf out of the pores of the stone. Only.

What advantage do you find from the slurry ? I have always wondered what the attraction was other than some intermediate polishing between stones but seems to slow down actual cutting of the blade material to produce an edge as fast as possible.

thanks

I prefer extremely weak bond waterstones because they expose fresh abrasive more rapidly than stones with a stronger bond, and do so even when used with very little force (I don't use much force when I sharpen). I don't care about the stone needing to be flattened frequently or that it is consumed quickly, I care only that it exposes fresh abrasive constantly to keep the cutting speed high, and that it makes a slurry easily even under low force.

I prefer to use waterstones with a thick mud on them because because it minimizes burr formation when using edge-leading or scrubbing passes, evens out the edge bevel finish aesthetically, increases the effective grit of the apex finish, and it seems in my experience that it is much easier to get a waterstone to keep exposing fresh abrasive as you sharpen if you start with a totally fresh and sharp layer of abrasive on the stone to start.

 

[Wowbagger]

I prefer extremely weak bond waterstones because they expose fresh abrasive more rapidly

it is much easier to get a waterstone to keep exposing fresh abrasive as you sharpen if you start with a totally fresh and sharp layer of abrasive on the stone to start.

Thanks.
I have a new appreciation for my old Norton 220. It does just as you say.
I thought it was a defective stone and stopped using it. Man is it soft. Makes a ton of coarse mud.

PS: look . . . do it yourself nagura stones. Ha, ha, just kidding. I just made small stones out of my old large Nortons when I got my Shaptons.

 

[cap'njake]

Thanks.
I have a new appreciation for my old Norton 220. It does just as you say.
I thought it was a defective stone and stopped using it. Man is it soft. Makes a ton of coarse mud.

PS: look . . . do it yourself nagura stones. Ha, ha, just kidding. I just made small stones out of my old large Nortons when I got my Shaptons.

What did you use to cut them with?

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Steel_Drake]

I've got a few more microscope images to share of some higher grit finishes on the Maxamet Mule. Again, each of these images shows a ~2.2mm length of the edge.

First up is a DMT EEF:


Sigma Power Select II 3000:


King 4000:


Naniwa Aotoshi (aka "The Green Brick of Joy") 2000

 

[ice-pic]

Those are great photos to me the King 4000 looks the keenest.
In fact I believe those edges are the best I have seen.
I hope to get close
The scratch patterns on my 10v edge are at least twice as coarse as the ones in your post.
I can only go to 1000 grit diamond WE system. Dragging my fingernail along the edge I
don`t feel a thing,but under the microscope I can see microchips that I can only guess at the size for now.
Maybe 1 or two micron.
I am going to purchase 3 Micron Diamond Stone and see what the results are.

 

[BluntCut MetalWorks]

Steel-Drake, thanks for follow up with nice images of maxamet edge after finished certain stone/grit.

My guess from angle perspective above, this would be around 80-85° (where camera is perfect vertical / perpendicular / 90°). Topographically obvious, EE surface is most flat/smooth vs others are bandy/lumpy/jagged. Without EM FOD, we can use brain to lower the viewing angle to less than 30°. Then much easier to see non-diamond affected surfaces are highly irregular dictated/sculptured by carbides. These same process, supposed/EE (or failed to/others) to create/shape the apex as flat as possible for given abrasive diameter.

For fun, you can enlarge these surfaces by a million times. Which surface would has best fluid dynamic? Or look other way, which surface trap most fluid?

 

[Wowbagger]

Duplicate

 

[Wowbagger]

What did you use to cut them with?

Cheepy Joe round rod hacksaw blade that comes with cardide grit fixed all around the rod.

I just scored the stone in a line all the way around a couple of mm deep then placed the stone over some wooden blocks and stuck it with a hammer to sheer it a lond the line of stress kind of like one "cuts" glass. Look in an old brick layers manual how to do it. I pretty much made it up as I went along but I think I saw my Dad do it once.

I think an improovement on the saw blade would be to deeply scratch a V notch shaped line all around to focus the stress more along a narrower line. My round bottomed line spread out the stess to cause lack of precision and a jagged line on a stone or two. Over all it did work consistantly just not cleanly.

Some just take their stone to a tile guy and have it cut through and through on a water cooled diamond tipped cicular saw table saw.

 

[HeavyHanded]

Cheepy Joe round rod hacksaw blade that comes with cardide grit fixed all around the rod.

I just scored the stone in a line all the way around a couple of mm deep then placed the stone over some wooden blocks and stuck it with a hammer to sheer it a lond the line of stress kind of like one "cuts" glass. Look in an old brick layers manual how to do it. I pretty much made it up as I went along but I think I saw my Dad do it once.

I think an improovement on the saw blade would be to deeply scratch a V notch shaped line all around to focus the stress more along a narrower line. My round bottomed line spread out the stess to cause lack of precision and a jagged line on a stone or two. Over all it did work consistantly just not cleanly.

Some just take their stone to a tile guy and have it cut through and through on a water cooled diamond tipped cicular saw table saw.

A tile wet saw cuts right through them. I've also used a diamond sawsall blade with a lot of water and it works well too, but takes a lot longer.