three finger sharp?

[eccvets]

nm nm nm

 

[somber]

I don't know what you mean, but Murray's hands are very rough, and my hands are very, very soft (I have something called Ehler's-Danlos Syndrome) and we both get the same 'results' when he checks a knife with the three-finger test, and then when I check a knife with the three finger test.

edit: you're not moving a little to feel it cut, you're moving a little and if you're doing it properly your nerves simply tell you, "Hey, buddy, you're gonna regret this move."

You know right away when it's done properly on a properly sharp knife.

 

[Javelin]

Its called "tickling the dragon" if i remember right, though three finger test just sounds less awkward lol

I like this test because I like an aggressive cutting knife. Don't get me wrong, I take my edges to where they'll whittle hair, but if not also aggressive its just not where I like it. Every try to cut open a piece of plastic or a potato chip bag and have that polished edge just slide over the materiel and not cut unless you put a little pressure on it? I hate that.

 

[KennyB]

I don't know what you mean, but Murray's hands are very rough, and my hands are very, very soft (I have something called Ehler's-Danlos Syndrome) and we both get the same 'results' when he checks a knife with the three-finger test, and then when I check a knife with the three finger test.

edit: you're not moving a little to feel it cut, you're moving a little and if you're doing it properly your nerves simply tell you, "Hey, buddy, you're gonna regret this move."

You know right away when it's done properly on a properly sharp knife.

Seems like kind of a tricky test because how much pressure to use, how much wiggle to use and what it should feel like is all kind of relative. It'd be nice to have a blade that Murray sharpened and do it on that to see what it should feel like.

I just gave it a shot on my Izula, didn't really put a whole lot of pressure on it, pretty much what I feel like I would put if I just wanted to touch something with my finger. Wiggled a bit, and it felt like it was cutting a little and like it'd slice right through with a little more pressure.

I dunno if I'd want to do that all the time. Kind of seems like one of those things that people do when they develop their own way to feel an edge out with just their fingers. I like to use the side of my index finger ( the side next to my thumb ) and put the knife edge on the inside, angled up so that I can slice the dermal ridges, so it's easy to tell if a blade is sharp if I can feel it catching and making those little micro-cuts, and if I went too deep or something the angle I hold it at make sure it wouldn't be a serious cut.

 

[meako]

ahhh yes grasshopper. that would be the " bleeding dragon crouching tiger roaring with pain test".

 

[somber]

Seems like kind of a tricky test because how much pressure to use, how much wiggle to use and what it should feel like is all kind of relative. It'd be nice to have a blade that Murray sharpened and do it on that to see what it should feel like.

Murray will sharpen any knife for $35, which includes priority shopping. If you watch Carter Cutlery's video on push cutting toilet paper you can see some hood examples on how this test is actually performed - I think you might be conceptualizing it incorrectly.

 

[Luis G.]

Murray will sharpen any knife for $35, which includes priority shopping. If you watch Carter Cutlery's video on push cutting toilet paper you can see some hood examples on how this test is actually performed - I think you might be conceptualizing it incorrectly.

You can get Murray to sharpen for $25 (including shipping if I am not mistaken) through an offer he extends to subscribers to his tips, generous offer given this is done by hand.

 

[cziv]

From the link on page 1 of this thread:

For anyone who doesn't know, the three finger edge test is where you place three fingers on your edge and VERY lightly wiggle them back and forth. If your edge is "Murray Carter" sharp, your fingers should feel the edge bite into the pads and prevent you from further wiggling them on the edge.

I don't see a word about moving the fingers "along the blade." If this quote is accurate, the test would be like dragging one's thumb or finger "across" the edge which is a whole different test and presents no danger of slicing you at all. If you make it 3 fingers, then it's even less likely to bite into tissue, since the weight is now distrubuted across the fingers.

I just did it as decribed above and wiggled my fingers "across" the blade of a new Spyderco Military and the fingers just bounced across the blade. Copy paper tells me more about my edge than this one. I may be doing it incorrectly but I followed the directiions and with a very sharp folder. :yawn:

 

[unit]

I believe "back and forth" refers to a motion oriented alond the edge (not "side to side")

The method is not widely understood IMO but neither are many other "tests" for gauging sharpness. It is all about what gives you the feedback you need to assess your results relative to your needs. In that capacity I think it is like many other subjects regarding sharpening (there is no "right" or "wrong", there are only methods that work best for some individual's needs/wants/desires).

Like him or not, the man's results are hard to fault.

 

[eccvets]

so for a succusful test, you would actually want the blade to sink in and actually cut into your fingers just a tiny bit?

 

[singularity35]

... It is all about what gives you the feedback you need to assess your results relative to your needs. In that capacity I think it is like many other subjects regarding sharpening (there is no "right" or "wrong", there are only methods that work best for some individual's needs/wants/desires).

You get to the heart of the issue once again Ken.

 

[unit]

so for a succusful test, you would actually want the blade to sink in and actually cut into your fingers just a tiny bit?

As I understand it the blade cuts into the dermis but not through it. With very light pressure you can feel the "bite"...too much pressure and you bleed. I imagine the tester would want to feel the bite with *minimal* pressure....it is not going to be everyone's method of choice

Obviously it is all relative to the pressure used and the condition of the skin (not unlike the educated thumb, the fingernail, shaving arm hair, etc.) ...all relative, yet perfectly acceptable to various craftsmen throughout history

There have been lists for gauging sharpness posted on these forums...I am not sure a single method has ever been mutually accepted by all. Some are quite interesting though.

 

[TwinStick]

I was curious about this method as well. I watched Paul Tsujimoto (Toooj) check knives using this method. Not one i would do, but i am just an enthusiast, not a pro like him.

 

[Ankerson]

As I understand it the blade cuts into the dermis but not through it. With very light pressure you can feel the "bite"...too much pressure and you bleed. I imagine the tester would want to feel the bite with *minimal* pressure....it is not going to be everyone's method of choice

Obviously it is all relative to the pressure used and the condition of the skin (not unlike the educated thumb, the fingernail, shaving arm hair, etc.) ...all relative, yet perfectly acceptable to various craftsmen throughout history

There have been lists for gauging sharpness posted on these forums...I am not sure a single method has ever been mutually accepted by all. Some are quite interesting though.

A guy checked one of my knives once, Military in S30V and pretty much sliced off the tip of his thumb and I told him it was Extremely sharp before I handed it to him.

I guess he didn't understand what sharp was.... He does now though...

In other words there ain't no way I wouldn't even think about putting 3 fingers on one of my edges.

 

[Jason B.]

The 3 finger test is just like the old thumb test but with 3 fingers so more of the edge can be examined at once. You do not move your fingers down the edge of any Sharp edge while testing but you do let it bite you just a bit. A fresh utility razor would be a good example of the level of sharpness and give you a base to go off of for feel.

If you cut yourself while feeling a edge then your doing it wrong.

 

[akula83]

Me too!

Hehehe once again you're right Marc, I missed "the whole length of the blade". I do like to do the catch a ridge thing. I like to feel how aggressive a cutting edge I wind up putting on my knife. The middle of my index finger becomes a maze of microcuts when I sharpen a lot.