Steels, sharpening, edge angles?

[Macintosh]

Been learning myself up on blade steels just enough to get myself into trouble. For the most part have always used knives with “genuine steel” blades, ie unspecified steel. Ive used some of the replaceable
blade knives and really dont care for them. Some knives Ive liked better than others, but dont really know which knife has which steel so cant really “look for” similar. On a Christmas whim I recently picked up one of the Ridge s90v knives for my wife and got one for myself to try at the same time—good black friday deal so I figured what the hey, Id try it. AFAIK its the only knife ive ever had with a really hard blade steel. I assume this is a cheaper version of s90v, which Im guessing makes it fairly brittle. Is this something that can be optimized a bit via edge angle? Would love any tips or wisdom on the topic of sharpening this type of steel for best result.

 

[fwafwow]

I’d check out bladeforums.com. I’m sure folks here can help, but that place is full of people who should.

 

[S-3 ranch]

Use diamond only to sharpen @ 20* angle
then strops with diamond paste
s90v imo is hard to sharpen but does hold a edge well with maintenance

 

[Macintosh]

Use diamond only to sharpen @ 20* angle
then strops with diamond paste
s90v imo is hard to sharpen but does hold a edge well with maintenance

What does “with maintenence” mean?

 

[Wrench]

I strop a few swipes every time I use it. They stay so sharp it's scary.

 

[yfarm]

Have always struggled with the angle and don’t want to mess with the angle device. Use a Smith 3001 10” diamond and hold the knife steady and move the sharpener against the edge, can actually feel the bite when you are the right angle. 2 or 3 swipes and you are done. Cleaning large pelagic fish, cutting thru bones keep it at the cleaning table. Have a small folding version goes in my pack for hunting, Knives of Alaska sell a small folding version that has a flat blade rather than the rod on the Smith, works easier.

 

[sndmn11]

20-25deg for that knife and it should behave like any other steel.

Create a burr
Rub the burr off
Polish the edge to the apex

I think people struggle with sharpening because they create a burr, and that burr will cut paper as well as shave hair on one side of the blade. When cutting meat/boxes/etc the burr folds over and the knife is dull.

When rubbing the burr off, you will be able to feel it in one side of the blade, then when you work that side with your sharpener, you'll feel the burr flip to the other side of the blade. You can also test this by shaving hair on one side, flipping the knife over and it will feel different when shaving. The goal is to keep rubbing/grinding/polishing until you can't feel the burr on either side. Then you are cutting on a true apex and a super steel knife will really shine.

"Maintenance" would then be a quick strop on both sides with light pressure.

 

[Macintosh]

You all strop with leather and a diamond paste, just leather, something different?

 

[intunegp]

CPM S90V is made by Crucible Particle Metallurgy and there isn't really a "cheaper version" unless the manufacturer has marked a different steel as S90V incorrectly. What can drastically change the performance of a given steel is the heat treat protocol...whether it was done correctly and whether the steel was brought to it's optimum hardness range. Many companies don't get this right.

S90V should be fine anywhere from 15-20° per side. As sndmn said make sure you're fully forming a burr on one side of the blade and removing it on the other. Stropping will help with burr removal. Diamond pastes have become the norm for stropping super steels, but because they are abrasive (even though at a super fine grit) you are continuing the sharpening process when using them. It is also easy to roll over an edge and actually reduce sharpness via stropping, especially with diamond compounds. Leather, cardboard, and wood are probably the most common strop materials whether using compounds or not.

Mastering sharpening is something that just takes practice and experimentation. What works for someone else might not be the solution for you. What works on one knife might not work as well on another. Try some different angles, different stones, and different strops and find a setup/process that works well for you.

 

[fwafwow]

You all strop with leather and a diamond paste, just leather, something different?

I have this - $8 on Amazon. Not diamond paste, but it works.

https://www.amazon.com/gp/product/B07941KX8R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[sndmn11]

You all strop with leather and a diamond paste, just leather, something different?

Cardboard, leather, ceramic. Gossman has s nice steel tool and I use the Spyderco triangle.

With use the feather tiny fingers of the edge get off line or roll. All you are doing when you strop is polishing to realign them, you aren't trying to remove material.

 

[Macintosh]

... What can drastically change the performance of a given steel is the heat treat protocol...whether it was done correctly and whether the steel was brought to it's optimum hardness range. Many companies don't get this right....

This is precisely what I meant--I dont know, but given the price relative to other knives I've seen using same/similar steel I assumed there were some corners cut somewhere. Just wondering if a situation like that would indicate a wider angle would be beneficial?
Thanks all--good advice, I have some basic tools but dont have a dedicated strop or any abrasive paste so have never really tried those in any real way. Will pick something up and get practicing. Keep it coming if there is more, but appreciate the replies very much.

 

[Macintosh]

Cardboard, leather, ceramic. Gossman has s nice steel tool and I use the Spyderco triangle.

With use the feather tiny fingers of the edge get off line or roll. All you are doing when you strop is polishing to realign them, you aren't trying to remove material.

"feather tiny fingers of the edge"--if I understand, there is no burr to realign at this point, and on a very hard steel the edge itself probably isnt rolling per se, but the fine scratches from abrasive sharpening result in something like a micro-serration on the edge, so you are realigning the tops of those?

 

[intunegp]

Just wondering if a situation like that would indicate a wider angle would be beneficial?

Not necessarily. Edge retention and perceived sharpness will increase as your angle gets lower. The trade off is durability. You just have to find the sweet spot for your uses. If you sharpen at 20° and find that the edge doesn't chip or roll with use, try 18° next time. If it does try 22°. You can continue to push this (wider or narrower) until you find the balance of edge retention and durability that suits you.

At the end of the day, if the steel is poorly heat-treated, it may never perform as well as even lesser steels that are heat-treated well. All you can do is find the optimum angle for a given knife for your use case.

 

[sndmn11]

"feather tiny fingers of the edge"--if I understand, there is no burr to realign at this point, and on a very hard steel the edge itself probably isnt rolling per se, but the fine scratches from abrasive sharpening result in something like a micro-serration on the edge, so you are realigning the tops of those?

I skimmed a couple pages on this website and it seems well done https://scienceofsharp.com/2014/04/16/the-honing-progression/

These are good pics https://www.knifey.net/blogs/knifey/knife-sharpening-myths-and-misconceptions

Sharpening Handbook

www.sharpeninghandbook.info

I think the micro serration concept is good to visualize, I don't know if it is from fine scratches or the carbides or from the knife getting used more frequently at a certain part of the edge but that part is irrelevant. The edge ends up with feather tips/microserrations and yes, you are realigning those through either microscopic abrasion or bending them back into place.


Here's some good photos https://prosharpeningsupply.com/blogs/knife-tool-sharpening/knife-sharpening-under-the-microscope

Freehand Sharpening with Microscope Pics

Took some pics this weekend of my sharpening process. Pictures are 1 mm wide and 1 mm high (edited with correct picture size, thanks Matus). Process for each stone was to raise a burr on one side, flip the burr, and then reducing the burr until I couldn't feel it with my fingers anymore. I've...

www.kitchenknifeforums.com

 

[Macintosh]

@sndmn11 thank you, those pics are great to visualize.

 

[Macintosh]

Man, I knew I wasnt well-versed in this stuff but just trying to learn a little I realize I have a whole lexicon to learn, etc. Reading some of these links is like a foreign language.

 

[Lawnboi]

Man, I knew I wasnt well-versed in this stuff but just trying to learn a little I realize I have a whole lexicon to learn, etc. Reading some of these links is like a foreign language.

Got get yourself a steel that’s a little easier to learn on. Trying to sharpen a cheaper s90v knife for a starter is like trying to learn to drive in a race car.

Good factory geometry is a big deal as well. Most knives you buy have crap edge geometry to begin with, and without straightening that out on a machine (easy) or by hand (harder) you will never get to the potential.

You have a lot of avenues to explore. Machines like wicked edge, stones, sandpaper, leather strops, diamond compound are all options.

It all depends what you want to spend. I can maintain an edge on my main Aebl steel game knife with some 5$ automotive sandpaper and a strop, but even that only lasts so long, eventually I reprofile the edge on a machine (I use tsprof)

Honestly best thing you can do is get a decent knife in an easier steel, use it in the kitchen till it’s dull and then practice.

Most don’t know how sharp you can get a knife with a proper edge.

 

[Macintosh]

Thank you. I do have a pile of other knives including some I know are softer (mora knife, etc) not to mention chisels, etc and stuff I've used to sharpen those in the past including some good quality stones plus a flat that I've clamped grit paper to to sharpen chisels. I'm not starting from scratch, just not assuming anything, but for sure will start slow trying to refine things.

 

[hereinaz]

I went down this rabbit hole years ago.

Get the angle right, clean up one side till you get a burr along the whole edge. Flip the blade and do the second side until you get a burr along the whole edge. I will hold the knife and run it against the “stone” or clamp the knife and run the stone against the knife. I do fine it easier with some knife/stone combination to do one or the other.

If the edge isn’t messed up or the blade geometry wrong from the start it doesn’t take much to create the burr. Slow steady full strokes on a good stone make fast work. Slow is smooth, smooth is fast or however that goes.

Go to polishing the bevel. Reverse the strokes on hone on a leather strop with compound until the burr comes off. I find the burr will come off as a dark line on the strop. I rotate sides as I strop.

The hardness of the blade just changes how much gets removed with each and requires a higher quality “stone”.

Also recognize that the razor edge of a blade will “roll” over cutting bone. So hitting it with a “steel” can straighten the edge and it will cut again. It’s why butchers use the round steel rod and why barbers use the strop as they work.