Method for determining knife blade quality

[criticalbass]

I'm not an expert on knife blades. I do own several knives of varying quality.

Some time ago I noticed that if one holds a sharp blade next to his ear and rubs a thumb across (not along!) the sharpened edge, it makes a sound.

In my experience, a raspy ring comes from high quality blades, and lower quality blades produce a sort of dull scraping sound.

I have tried this on quite a few blades. Doesn't seem to work unless the blade is pretty sharp, and may not work for everyone.

Since I have already admitted lots of ignorance regarding knife blades, has anyone else noticed this?

(I considered going into knifemaking years ago. Did some reading and visited several knifemakers. Also went to a few club meetings of knife makers. Came away with nothing but respect and admiration for the craft, and decided not to invest the time and money it would take to make high quality knives.)

 

[BrandonM]

Blade thickness would make a ton of difference in the auditory tone produced. I don't think there is any validity to a sound test. To many variables.

 

[criticalbass]

Blade thickness would make a ton of difference in the auditory tone produced. I don't think there is any validity to a sound test. To many variables.

You had me more than half convinced. I started digging for my Knives of Alaska set (thick as a hatchet), which I seem to have misplaced, but in the search came up with five filet knives ranging in quality from great to junk. All are near the same thickness (thin).

I made sure they were all sharp and tried the auditory test. The best ones made a scratchy ringing sound, and the lower quallity ones didn't. This may just be "psychoceramic" with me, but I'd like for someone else to give it a try. By best ones I mean those that hold an edge the longest.

 

[dennishoddy]

Lol, I couldn't hear a subtle "ring" if you ran a bastard file across it.

 

[Fyrtwuck]

Knives as tuning forks....hmmmmmm

 

[mike miller]

Hey don't make fun of the tuning fork. Jerry Larison makes a big chopper which he has incorportated the handle as a tuning fork so when it hits the sweet spot you can tell it.

 

[criticalbass]

Dennis, without my hearing aids I am damned near really deaf, but my right ear is better with high frequencies.

So far, nobody seems willing to dig into their knife stash and see if the results are anything like what I have observed.

 

[Capm_Spaulding]

I research the knife if it is made from a big company, or I ask the person what they used if it is hand made. Technique wise... Idk other than a paper test or something. "Quality" is a relative term when it comes to knives, if you want a finer, sharper edge, or longer durability. s30v steel is the best in my opinion and I don't generally buy anything else as it is a really good in between. but that's just me, it's all what you like really. One of my favorite knives is one my dad ground down from an old Chevy bumper, it has held a better edge than anything I've owned and it's been well abused. After a certain point, it's kind of like saying my Lambo is better than your Ferrari, they both beat the hell out of what everyone else drives so it is simply preference at that point unless you want to be the absolute king lol

 

[ez bake]

Not true.

"Quality" of a knife steel is subjective in the first place (it's far more complex than Good vs. Bad), and some steels have specific properties that are more/less desirable to the owner - stainless, toughness, edge-retention, abrasion-resistance, etc. and the quality/level of heat-treat will affect this even more so.

Quality and type of sharpened edge will change the sound it makes when dragging your thumb across (I assume you mean perpendicular to the edge - even then be careful, I've got some knives that will dig in even if going across the plain of the edge-apex).

With my knives, should you want to tell if it's got a quality edge on it drag your thumb across it and if your thumb is bleeding, it's a good edge

 

[Droberts]

if your goal is a quality blade start by refusing to purchase one unless you know the exact metal that was used and what hardening and tempering process the blade went through. if that information is not available look elsewhere.

if you want a high quality knife to use for the rest of your life find a bladesmith and have him make you one out of 1095 steel, differentially hardened and tempered correctly.

using the sharpness of a blade as a single metric for quality is the wrong way to do it.

edit:
here's an example of what im talking about.
[Broken External Image]