Sharpness obtained with different steels

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Ouch2001

Joined
Jan 7, 2001
Messages
21
I'm just wondering what steels can be sharpened to the best edge. I've noticed that some of my knives seem to take and incredible edge only to degrade rapidly while others take a great edge and seems to stay there for a while. My Spyderco Viele w/ VG-10 seems to be one of them. I cut up a load of boxes recently and when I was done the edge was still shaving sharp.

I'm wondering if someone has compiled a list of steels and their obtainable edges. I've read on the forums in many posts that some steels will only take a certain edge, say sharp (sliceing paper) vs. really sharp (shaving) vs. scary sharp (able to cut a free hanging hair). This I think would allow me (a novice) to gauge my sharpening techniques. If my BM735 w/ 154CM blade is capable of a scary sharp edge and I'm only getting a really sharp edge, then I have something to work on but if thats the best edge 154CM can take I've done pretty good. Hope my request is clear. TIA for all the reply.
 
Ditto that request. My Microtech LCC is what I consider to be a very very sharp knife. My William Henry Wharncliffe Evolution with VG-10 steel is even sharper. Is it possible that some steels allow for a finer edge?
 
Some alloys are very fine-grained and take a razor edge with many different honing techniques and equipment. In general the non-stainless steels are pretty easy. This includes 1075, 1084, 1095, A2, O1, 52100 and Carbon V. The stainless steels are subject to having larger and harder carbide grain and can be more challenging to sharpen. Alloys with vanadium and/or tungsten like AUS-8, AUS-10, VG10, and BG42 are examples that get scary sharp with dependably. Some high-purity, moderate carbon content alloys like 420HC and Sandvic 12C27 easily take very sharp edges (particularly 12C27).

The difficult group are the harder stainless alloys that have a lot of chrome and/or molybdenum like 440B, 440C, and ATS34 can be hard to sharpen. It depends a lot on heat treatment. It particularly helps if these are cryo treated to reduce grain side. I often find 440 series alloys that truly take diamond hones to do anything good with.
 
Taking an edge and holding an edge are two totally different things.
With adequate technique, you even can sharpen butter (just deep freeze it before honing).
Keeping an edge is a VERY complicated matter, worth several PhD-thesis. Depending on steel, its heat-treatment, cutting angle, edge finish, material you cut, method how you cut and several more parameters...
Happy sharpening
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Ted
 
I've generally found what Jeff Clark has found. I ran into this pretty unexpectedly. I noticed that I was able to put an incredible edge on a particular 8A knife I had. Because 8A is obviously a cheaper steel, I was surprised that this knife's edge beat out all my ATS-34 blades' edges. Somewhere along the line I figured out that the addition of vanadium was the unifying factor in stainless blades taking an incredible edge, and then I saw the theoretical basis about how vanadium refines the grain structure.

Joe
 
I am a fan of carbon (low chromium) steels for the reasons Jeff so succinctly explained. They are easier to create and maintain super sharp edges. The grain size of the steel is important when you are talking about the properties of metal at the very small scales of the final cutting edge.

Heat-treatment of the steel is the most important parameter to determining the final working properties of the edge. But as Ted points out, 'sharpness' depends on a whole bunch of other factors besides just the steel alloy.

No woodcarver I know uses tools made from 'stain-resistant' steels. In woodcarving, the highest degree of edge sharpness is required for push cutting. High chromium steels usually create tools that will not get as sharp as carbon steels (in my opnion only). 420V and other particle metallurgy steels may change my opinion about that, but 420V is many times more expensive than the simple carbon steels.

In this current thread I said these sort of questions are like going down the rabbit's hole to Alice's Wonderland: Another Steel Question

Things get really weird and confusing.

Ted, I think you may have just redefined the term 'butter knife'
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Paracelsus
 
While I agree that there is a difference in obtainable sharpness for various steels in regards to the level of polish they can take - very few people would be able to tell this difference as it is beyond a level of sharpeness to which most knives are ground.

Many people have problems with the high alloy high hardness steels because of the method of sharpening and/or the abrasive. Soft abrasives like AO will not cut these steels well and frequently cause high pressure to be used during sharpening which makes the situation worse by creating a large burr.

Diamond hones will sharpen all steels easily, even the hardest most wear resistant ones and used with low pressure will vastly reduce the extent of formation of a burr.

I have never seen a steel, and I have seen many, that I could not make shave very easily nor do many things that are commonly used to grade sharpness (push cut through newsprint, slice through a vertical roll or newsprint etc. ).

But I know from talking to several makers like R. J. Martin, I cannot sharpen knives as well as they can, so for them there may be a difference in obtainable sharpeness, for me I have yet to see one.

However I am planning to upgrade the abrasives I have later this year (1200 and 2000 grit diamond benchstones, 8000 grit japanese waterstone, sub micron belts, buffer etc.), and work on my sharpening technique. Maybe I will see a difference then.

-Cliff
 
Sharpening technique is an interesting parameter indeed. The shapest edge I have ever obtained on a knife was on a knife that I made out of 440-C. I wanted to ship it out to the new owner right away and after getting fed up with the stones I was using, I pulled out my grinder. I am a very new knife maker (I have finished 4 knives) and I was apprehensive to sharpen a knife on a grinder. But, in a very short time I had the ebst edge I have ever put on a blade, and it was "only" 440-C steel.

By hand, the sharpest edge I have ever put on a blade was on an AUS-8 MAC brand kitchen knife, but the thin blade was a big factor too.

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"Come What May..."
 
THANKS! That "splains" alot. I am largely ingorant of steel characteristics but recently picked up my first 8a blade. It is incredible! It sharpens easily to hair-popping sharp and takes a great deal of abuse before noticeable dulling. Many better characteristics than MUCH more expensive steels. (It won't be my last 8a!!)
 
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