Able to get some knives shaving sharp and others not as much?

[Skane24]

I’ve been able to get quite a few knives shaving sharp, steak knives pocket knives etc, however I’m struggling to get any of my chef knives shaving sharp, they slice through paper easily, angle is anywhere from 15-20 degrees depending on the knife.

I’ve noticed that softer steels seem to get more sticky sharp than harder steels, I’ve been using a KME, diamond stones, 140-1500 then strop with kangaroo leather with green compound. Is there a reason why I’m struggling with chef knives so much? I get a full burr from heel to tip on the chef knives, bevels are even.

Any advice is appreciated, thank you for your time.

 

[3D Anvil]

Since you've gotten a full burr, you've apexed the blade. If it's not very sharp, the problem is either that you haven't fully removed the burr, or you've rounded the apex while attempting to remove the burr. Are you stropping by hand, or using KME strops?

 

[Skane24]

Since you've gotten a full burr, you've apexed the blade. If it's not very sharp, the problem is either that you haven't fully removed the burr, or you've rounded the apex while attempting to remove the burr. Are you stropping by hand, or using KME strops?

Using kme strops, I pretty much only use the weight of the strop+ a tiny bit more, to make sure to not round the apex, when doing the grits, I always use 6 upward strokes per side when finishing, then 5, 4, etc etc then move onto the next grit, and then do the same.

 

[Obsessed with Edges]

Depending on the steel type (what is it?) used in the chef's knives, the green compound stropping may not be ideal for it. That's the first variable I'd look at.

In steels with much wear resistance, green compound on leather can sometimes just burnish or round the apex a little bit. It works well on simpler carbon steels and low-alloy stainless steels like 420HC. But with something a little more wear resistant, i.e., with hard carbides, other compounds might be better suited for those.

 

[Skane24]

Depending on the steel type (what is it?) used in the chef's knives, the green compound stropping may not be ideal for it. That's the first variable I'd look at.

In steels with much wear resistance, green compound on leather can sometimes just burnish or round the apex a little bit. It works well on simpler carbon steels and low-alloy stainless steels like 420HC. But with something a little more wear resistant, i.e., with hard carbides, other compounds might be better suited for those.

Alrighty, is there any type of compound that would be better suited for those steels? I have the CBN emulsion kit but don’t use it much. I can also just try to use just stones, and do upward strokes with less and less pressure to remove 99% of the bur.

I’m gonna try to do a few knives these evening and see where I get. I really appreciate everyone’s help!

 

[Obsessed with Edges]

Alrighty, is there any type of compound that would be better suited for those steels? I have the CBN emulsion kit but don’t use it much. I can also just try to use just stones, and do upward strokes with less and less pressure to remove 99% of the bur.

I’m gonna try to do a few knives these evening and see where I get. I really appreciate everyone’s help!

Steels with sort of middle-ground wear resistance, i.e., with more wear resistance than simple carbon steels or low-alloy stainless, respond well to aluminum oxide compounds. Those would include polishing pastes like Flitz, Simichrome and stick-type buffing compounds in grey aluminum oxide or white ('white rouge'). Those work especially well on fabrics like denim, canvas or linen.

Steels in that middle-ground category, like VG-10 for example, are sometimes used in fairly high-end kitchen / chef's knives. That's why it's important to know which steel you're dealing with, in choosing good stropping options for them. The CBN emulsion you already have might be a good place to start - it should handle such steels easily as well.

And by all means, do as much as you can with the stones, before going to stropping. Stropping is always more effective on edges that are truly ready for that step, but will struggle if the edge isn't quite ready. Edges that're still a little too blunt or thick will tend to be rounded off by stropping.

 

[Skane24]

Steels with sort of middle-ground wear resistance, i.e., with more wear resistance than simple carbon steels or low-alloy stainless, respond well to aluminum oxide compounds. Those would include polishing pastes like Flitz, Simichrome and stick-type buffing compounds in grey aluminum oxide or white ('white rouge'). Those work especially well on fabrics like denim, canvas or linen.

Steels in that middle-ground category, like VG-10 for example, are sometimes used in fairly high-end kitchen / chef's knives. That's why it's important to know which steel you're dealing with, in choosing good stropping options for them. The CBN emulsion you already have might be a good place to start - it should handle such steels easily as well.

And by all means, do as much as you can with the stones, before going to stropping. Stropping is always more effective on edges that are truly ready for that step, but will struggle if the edge isn't quite ready. Edges that're still a little too blunt or thick will tend to be rounded off by stropping.

So, I’ve managed to get a chefs knife shaving sharp, broke out the microscope, made absolutely sure to fully apex and form a nice big burr, then shaved the burr down each grit, then stropped after 1500 diamond stone.

I hate to admit this but, I thought one some of these tougher steel knives there was “less” or a “smaller” burr, and I don’t know if I was 110% fully forming a burr. I broke out the microscope to confirm 110%.

Managed to shave and whittle hair, however I’m still having a little trouble fully easily push cutting paper towels hah!

Can I achieve a push cutting of paper towels, tissue paper etc with the gear I currently have?
I’m still relatively new to all of this, and still learning

I appreciate everyone’s patience and advice!

 

[Obsessed with Edges]

So, I’ve managed to get a chefs knife shaving sharp, broke out the microscope, made absolutely sure to fully apex and form a nice big burr, then shaved the burr down each grit, then stropped after 1500 diamond stone.

I hate to admit this but, I thought one some of these tougher steel knives there was “less” or a “smaller” burr, and I don’t know if I was 110% fully forming a burr. I broke out the microscope to confirm 110%.

Managed to shave and whittle hair, however I’m still having a little trouble fully easily push cutting paper towels hah!

Can I achieve a push cutting of paper towels, tissue paper etc with the gear I currently have?
I’m still relatively new to all of this, and still learning

I appreciate everyone’s patience and advice!

Push-cutting gets easier with thinner blade geometry and narrower edge angles. Once you start going lower than 15° per side (30° inclusive), there's a noticeable jump in ease of cutting. Depending on the steel and its capabilities for edge-holding, you might be able to go down to 10°-12° per side or so. But some simpler, less hard steels may be a little too flimsy at the edge at such narrow geometry, depending on what you're doing with them in use.

Some better steels can form very strong & stubborn burrs, even at fairly high hardness of HRC 60 or so. Kitchen cutlery in VG-10 is an example of this at times, and can take more work to clean up the edge after sharpening. The burrs themselves reveal the attributes of the steel (strength, toughness or brittleness, ductility) oftentimes. So a lot can be learned about the steel and its heat treat by watching how the burrs behave.

 

[3D Anvil]

Using the CBN emulsions, or lapping films, will take you to that last level with the equipment you have.

 

[garry3]

Geometry is king with my kitchen knife's. No amount of edge refinement can overcome poor geometry. Thin behind the edge and a bit of convex edge bevel is what I prefer. If I get to acute and refined with the edge angle the knife will get sticky on the board. I will back off on edge refinement and or angle.

A harder steel is easier to sharpen, gets sharper and holds it better. I prefer the plain carbon steels in the low 60's rc but they are not for everyone. I haven't tried all the stainless out there though like AEB-L, HAP 40 and ZDP-189. I probably won't because I enjoy sharpening the plain carbon steels and can't justify the extra cost with some of those steels when less expensive steels perform so well. If I worked in a professional kitchen that opinion would probably change.


I leave the softer steels with more obtuse edge angles and more tooth. I think those type of edges last longer with the softer steel. They still benefit from being thinned behind the edge and a convex edge or just knocking the shoulders off of the edge bevel gives me the same effect as a convex edge.

 

[cudgee]

Push-cutting gets easier with thinner blade geometry and narrower edge angles. Once you start going lower than 15° per side (30° inclusive), there's a noticeable jump in ease of cutting. Depending on the steel and its capabilities for edge-holding, you might be able to go down to 10°-12° per side or so. But some simpler, less hard steels may be a little too flimsy at the edge at such narrow geometry, depending on what you're doing with them in use.

Some better steels can form very strong & stubborn burrs, even at fairly high hardness of HRC 60 or so. Kitchen cutlery in VG-10 is an example of this at times, and can take more work to clean up the edge after sharpening. The burrs themselves reveal the attributes of the steel (strength, toughness or brittleness, ductility) oftentimes. So a lot can be learned about the steel and its heat treat by watching how the burrs behave.

Very informative post. I just reprofiled a cheap made in Japan stainless steel mini-cleaver style knife. As an experiment went down to 12 degrees per side and finished on 1000 grit ceramic rod. It will slice anything and has been a great little kitchen knife so far, be interesting to see how it holds up. But just have to give it a few swipes on the ceramic rod to bring it back to really sharp.