Is my knife really sharp?

[nksmfamjp]

I have been knife sharpening with my Spyderco Sharpmaker again. I can get my knives pretty sharp, but I'm somewhat unclear if they are sharp coming off the sharpener.

So, the first thing I did was grab the marksalot and my optivisor that has like 20x magnification on the top end. this helps me see that the whole blade edge is being dressed and that the burrs/damage are invisible to 20x, but how do I know if it is really sharp?

How do you do it? I've tried paper and can tell cutting vs ripping, but it seems like I should be able to see this better.

 

[Coyote Shadow Tracker]

I got the same sharpener and our knives come out scary sharp. Now it depends a lot on the steel that you are trying to sharpen. Some steel is tougher to sharpen than others but hold the edge longer. ATS-34 (154CM), and the SV30 & SV90. Now if you get a Carbon Steel like 1095 or 52100 like in Marbles Knives sharpen rather fast and are scary sharp.
You may have some really good steel in your knives and just need to take a lot more strokes on the Ceramic Stones.
OR the steel in your knives just won't hold a super sharp edge.
You also need to look at the degree of angle sharping the blade. Some blades & steel do better with a certain angle.

As far as knowing how sharp it is, well if you pick it up and touch the blade and cut yourself it's sharp DON"T DO THAT. We have an older Marbles knife in our collection and have to warn anyone that looks at it to hold it. Had several people admiring it and try to touch the blade to see if it is sharp and cut themselves.
We have a 2K Digital Microscope but don't look at the edges. You can look at the "Hairs" of steel on the edge. I know all our knives so just know if they are sharp. Also do the paper test.
What brand knives are you trying to sharpen, and do you know what steel is in them?

 

[Darryle]

Do a thumbnail test, if they catch on the nail, they'll cut.

I use a JET wet sharpener at work, I do the thumbnail test and every edge that passes that test will cut, regardless of what material you are trying to cut.

 

[victor3ranger]

I have been knife sharpening with my Spyderco Sharpmaker again. I can get my knives pretty sharp, but I'm somewhat unclear if they are sharp coming off the sharpener.

So, the first thing I did was grab the marksalot and my optivisor that has like 20x magnification on the top end. this helps me see that the whole blade edge is being dressed and that the burrs/damage are invisible to 20x, but how do I know if it is really sharp?

How do you do it? I've tried paper and can tell cutting vs ripping, but it seems like I should be able to see this better.

It's getting fairly sharp when it can clean shave in one stroke.

 

[Critter Picker]

I love my Spyderco sharpener. I use the shave method to check sharpness.

 

[renagde]

If you can whittle a hair, it's sharp. I can get my knives so sharp on my Wicked Edge that I can take a hair follicle and whittle it like a twig.

 

[Weaver93]

I use the stupid test. Inevitably shortly after sharpening a knife I will cut myself. If the cut is so clean that it only shows itself by weeping small blood droplets and burning like sin it is sharp. If the cut is gaping and bleeds profusely the blade needs a couple more passes on the stone.

 

[oldfortyfiveauto]

Been using both an Edge Pro and a Tormek. The thumbnail test works for me.

 

[Bob Wright]

I drag my fingerprints across the blade and look down the blade edge to see if it has zero shiny spots as I sharpen. Those shiny spots are either dull or nicks.

 

[HSmithTX]

If it will shave the tops of the ridges off your fingerprints you are done sharpening. Check this using your optivisor. When dead sharp the edge feels 'sticky' like it wants to stick to your fingernail or your fingerprint. It might not feel super sharp with how careful you have to be compared to a rougher edge but it is sharp. This is what I call scary sharp. The edge itself will also look like a mirror in your optivisor, you need relatively good steel to start with and depending on how good the steel is the edge will hold for a long time or it won't hold up that long. On really good steel this edge will last a LONG time, just 2-3 LIGHT strokes on each side on your steel rod will get it back to scary after dressing several deer or a couple of hogs and you won't even remember the last time you sharpened it. On lesser steel this is also the longest lasting edge you can get but how long it lasts depends ultimately on the steel.

 

[victor3ranger]

I have 2 secret things that will make knives like razors but I need someone who has access to old school high voltage lights

 

[VinceMule]

try slicing bread instead of paper, world of difference between what you think is a sharp knife and a sharp knife!

 

[P7M13]

I use the ripe tomato test.
If I can shave slices off a ripe tomato without doing anything more than barely pressing straight down on the blade, I'm happy.

 

[VinceMule]

Try the slice of loaf bread