All About Pocket Knives

I see in this section many threads about various ways to achieve a sharp edge. What I do not see is how you are testing that edge to determine if it is sharp.

So, boys and girls, what is your favorite method for testing the edge of a newly sharped blade?

Thank you.

Kevin

I usually take a piece of paper and slice the edge. That's sharp enough for me. ftd

I pull it across my thumbnail. If it grabs, I'm good.

Steve Warden wrote: ↑Sat Oct 26, 2019 12:10 pm I pull it across my thumbnail. If it grabs, I'm good.

Yup, the old thumbnail test for Me.

I see if it will shave the top of my forearm dry.

I treat it worth the pad of my thumb. If it feels , then I see if it’ll shave arm hair. If it does it’s good.

What the Colonel said ^. I might not go to shaving sharp, depending on the knife, anticipated use and steel. Seems some of the "super steels" will lose shaving sharpness with a few days or weeks of use...then hold an acceptable / user edge, for a long time. I don't fret over shaving sharpness...at the expense of metal.

Good ideas, all of them.

When I first started I used slick magazine paper. Fold up about 1/2” and test against that. Then I progressed to the yellow pages. Then to cash register tape. I now use 3” thermal cash register tape. It comes in rolls so it is easy to carry and use. It is not quite flimsy but you need a sharp edge to slice it. I try the edge about an inch from my fingers.

Kevin

Steve Warden wrote: ↑Sat Oct 26, 2019 12:10 pm I pull it across my thumbnail. If it grabs, I'm good.

X2.

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Mike

I do the thumbnail test. Pull the entire length of the blade choil to tip across my thumbnail with the blade perpendicular to the floor and thumbnail slanted at about 45 deg. Just the weight of the knife and blade on the nail holding the knife at the very end opposite the blade tip.The blade should stay put as I move it and not slide off the nail. Dull spots on the blade will cause the blade to slide off the nail.

I also do the arm hair shaving test if I want a shaving sharp edge.

Same here as several have said already. I use the "pad" of my thumb to feel the edge. With a little experience feeling various edges you can tell how sharp it is. I also use the hair on my arm to test for shaving but rarely sharpen my knives to that point. I just don't find a shaving edge to be needed and sometimes it's a detriment.

I did encounter one knife, a custom fixed blade my son bought at a gun show, that was so sharp it cut my thumb when I felt the edge. Sharpest knife I ever saw!

Ken

At home I usually use phone book paper for the initial test but my favorite way to test sharpness is to cut some shrink wrap while it's tightly wrapped around a pallet. We have hundreds of shrink wrapped pallets at my workplace on any given day.

Once I get the blade sharpened to my satisfaction I'll take the knife to work with me and do a final test on some shrink wrap. The shrink wrap is delicate and it responds well to any imperfections that I might have missed along the edge. Fortunately, I rarely need to do any follow up honing but I use the final shrink wrap test to confirm that.

Pad of thumb. I have very thin skin and I can tell if it is sharp enough for me to smile, very quickly this way. On a related note, I am not very good at achieving this sharpness.
On an unrelated note, it seems to me that knives lose sharpness to a degree, just sitting. Am I nuts?

tongueriver wrote: ↑Sat Oct 26, 2019 4:43 pm Pad of thumb. I have very thin skin and I can tell if it is sharp enough for me to smile, very quickly this way. On a related note, I am not very good at achieving this sharpness.
On an unrelated note, it seems to me that knives lose sharpness to a degree, just sitting. Am I nuts?

Probably, but that is beside the point!
Seriously, I haven't noticed that, but I imagine that the steel would be more prone to oxidation on a microscopic level when it is that thin.

Colonel26 wrote: ↑Sat Oct 26, 2019 12:47 pm I treat it worth the pad of my thumb. If it feels , then I see if it’ll shave arm hair. If it does it’s good.

Exactly the way my Dad taught me!

tongueriver wrote: ↑Sat Oct 26, 2019 4:43 pm Pad of thumb.

Same here.

tongueriver wrote: ↑Sat Oct 26, 2019 4:43 pm Pad of thumb. I have very thin skin and I can tell if it is sharp enough for me to smile, very quickly this way. On a related note, I am not very good at achieving this sharpness.
On an unrelated note, it seems to me that knives lose sharpness to a degree, just sitting. Am I nuts?

I’ve noticed some of my knives do seem to lose sharpness spring around and some don’t seem to. I have no idea why but I have noticed that.

Colonel26 wrote: ↑Sat Oct 26, 2019 9:46 pm I’ve noticed some of my knives do seem to lose sharpness spring around and some don’t seem to. I have no idea why but I have noticed that.

That's because them boys are sneakin' 'em and trying to cut barbwire with 'em.

jerryd6818 wrote: ↑Sat Oct 26, 2019 10:08 pm

Colonel26 wrote: ↑Sat Oct 26, 2019 9:46 pm I’ve noticed some of my knives do seem to lose sharpness spring around and some don’t seem to. I have no idea why but I have noticed that.

That's because them boys are sneakin' 'em and trying to cut barbwire with 'em.

Hmmmm. I do see them ogling my edc Knives occasionally. You might not be far off!

I recall a thread in BF years ago in which many people posted that their knives did loose sharpness over time when in storage. Some were people who claimed to be good at sharpening and then knew the level of sharpness that they brought the edges to. Then after a year or two, this level of sharpness was no longer present.
A few metallurgists discussed the edge at the molecular level but could not account for the observed dulling.
When doing 'slice the hanging paper' test, how far from your pinch grip on the paper do you slice ? Someone has said 1". I try at about 3" on newsprint.
kj

After sharpening I push the edge of the blade into my thumb nail, on the flat, thoughtfully.
Blade at an angle. If it is sharp it will catch immediately.
I try this at the tang and several places up the blade to the tip. I try the other side. Same method.
If it slides I go back to the stone until I get the results I want. A sharp edge.
I can't tell you the last time I shaved hair on my arm. I'm not interested in that.
I tried to cut paper awhile back after sharpening. I was surprised it didn't cut it very well. I don't care.
I put my wonderful knife in my pocket and moved on.

I think blade edges will loose a fine cutting edge in storage. Just noticeably less sharp. I remembering this happening to me. Once.
It probably has happened without my noticing it. Of course I have no explanation for it.

Great thread. It's nice to see sharpening discussed.

I cut a ripe tomato. If it cuts easily it's sharp. If it doesn't, resharpen.

There ya' go. Tomatoes are a good test.

1967redrider wrote: ↑Sun Oct 27, 2019 1:35 am I cut a ripe tomato. If it cuts easily it's sharp. If it doesn't, resharpen.

I have done that when sharpening at Farmers’ Markets. Sometimes with a pepper. Except for the waste of food, a great visual test for customers to witness.

Kevin

Cutting a tomato is a lot like slicing bread. A "toothy" edge works better than a shaving edge. Same for cutting steak.

Ken