Testing for Sharpness

[CliffCurry]

As sharpening skills increase and the amount of available arm hair has diminished   I have sought out new tests that allow the amazing edge keenness achievable with the WEPS to be shown.

My standard baseline test has always been push cutting news print but feel that its time to up the ante.  Heres a nice demo of dull vs sharp as a baseline similar to what I use…

I did do this in the past for fun once, its impressive to see…

And this one looks fun to try…

Ofcourse for “feel” the Murray Carter method, but caution should be taken to listen CLOSELY to what he says…

For an “ultimate” level testing is harder without special jigs n gear.  Heres a well done example of higher end results we can achieve on the WEPS…

Please share your own methods that you use for testing….

2 users thanked author for this post.

Mark76, Alan

[Snecx]

Shaving arm hair is my favourite method. I think I caught this habit from Clay in his sharpening videos.

[CliffCurry]

Yeah you can tell a lot just from arm hair by how it “pops” 🙂
All depends how far down the rabbit hole you go….forgot to link Frans van de Kamp’s awesome vertical slice of a cigarette paper!

[Anonymous]

I’ve seen some cheating in these Videos… eg. I saw a cigarette that was placed on the top of a stick, but not really, it was placed down in a bored hole in the top of the stick, I’ve seen a dozen granny smith apples lined up on a wooden beam , and each was sliced in half with a single stroke in one motion… the problem with that is all the apple were pushed onto a 3/4 inch embedded dowel in the table… giving the allusion that the apples were just sitting there.. More magic illusion than anything.. no doubt the knife was sharp, but when a demonstration uses slight of hand or trickery, it says something about the validity.

I now  know what a sharp knife is, I also know it can be sharper, it can always be sharper… but my edges have gone from a 4 to a 7 on a scale from one to 10. It may take me the rest of my life to move that scale one or two placed. I’ve moved that scale three places in the last two months thanks to the WEPS and some research, helpful people, and understanding.

Bill aka ET

[CliffCurry]

Glad your having fun Bill, I was thinking of you(and others) when I posted this so you could have a few new ideas how to test for increasing levels of sharpness as your knives continue to progress.  Hopefully people will share more if they know of them…

To my own shock my kitchen knife wouldnt pass the free standing folded paper test so guess what I was working on today.  That ones a bit tougher then it looks, or maybe my paper is damp…yeah thats it, damp paper! 

[Anonymous]

There is another issue.. getting sharper is always a good thing but at some point, there has to be a point where a sharp knife needs attention every time you use it.  There are steels that are extremely hard and offer good steel retention, but they are also more susceptible to chips and nicks.  So not only is there a sweet spot with the sharpening set up, There is also a sweet spot in the specific use or potential hazards of a knife that is too sharp in the normal function of its purpose. e.g. slicing and chopping. One offers a gentle termination, and the other offers a high impact termination.. use a hard very thin sharp edge on a carrot, allow it to strike through and hit a chopping board and your 9* or 10* angle can bend and chip away, if it’s at 64/65roc.  So is there a consensus about hard steel, acute angles, and function.. Chopping and slicing are two completely different disciplines. Both will like a sharp edge, but when does the purpose effect the choice of how you sharpen a knife.  You can always use a less hard steel, that can handle impact but soft steel wont be as sharp, and maintain that sharpness. Usually I find that a middle of the road ( anything ) one that has a wider range of function , does a poor job at either end of the spectrum. Where as a knife that is specific for chopping should be designed and sharpened for chopping. I knife designed to slice through flesh, should be specific for that purpose. If a flesh slicing knife will see bone, then that knife should be designed for that purpose.  You would not use a butcher’s cleaver with a 9* degree angle. you would not get through a single rack of pork chops.

 

[Anonymous]

AS far as these test of sharpness go….its a demonstration of sharpness. but its a very poor example of function,

I don’t go out of my way to cut through a piece of cigarette paper…or even slice through a phone book page. there is no reason to do so… its an impressive trick. But the reality is, you can do that with any sharp straight razor.. but would you use a straight razor to cut pork chops, or chop carrots? No.

So understanding function is the first consideration in the sharpening process… Selecting the right steel for a specific purpose is part of the knife selection phase. the buying step.

If you are gong to use one knife for a multi purpose knife, it will be just ok.. for general tasks in the kitchen, But having a knife specific for each task will be much better in that specific function. Just some observations.

Bill aka ET.

[Anonymous]

I am having fun….:)

 

[CliffCurry]

Bill, I learned much by watching videos done by Cliff Stamp.  He has high level knowledge and applies it at a ground floor level with rigorous testing.  You may enjoy those…

The general idea(someone correct me if Im getting this wrong) is to narrow the bevel angle….for whatever knife, steel, or specific used…until it fails either by buckling or chipping during use.

The solution:  Increase the angle by a degree or 2 and test again…until it doesn’t and viola you have found the optimum angle for that knife/steel/use.  Cool beans? 

[CliffCurry]

As far as a practical, easy to do test for sharpness, to determine a level of refinement in the apex of a secondary bevel?   I still like the whittling hair test…just dont pull it out of your wifes head(she seems to not like that so much!)

Kitchen knife I was doing some testing on tonight.  Im happy with the results of new technique!

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3 users thanked author for this post.

wickededge, Mark76, Gib Curry

[Mark76]

I do use my girlfriend’s hair . It’s much thicker than mine.

Molecule Polishing: my blog about sharpening with the Wicked Edge

3 users thanked author for this post.

wickededge, CliffCurry, Gib Curry

[tcmeyer]

This is a re-post from the “stroping” thread:

The best test I’ve found is inspection with the USB ‘scope.  I look directly down on the edge and focus on the apex, then slowly move from heel to tip.  A truly sharp edge will reflect no light.  Even the smallest burr will show up as a glint along the edge.  If the edge looks good at 50X and I really want the sharpest edge possible, I will go to 180X and reinspect the full length again.  Of course, each blade get the paper slicing test before sending it home.

I will also inspect for a centered apex by holding the ‘scope dead vertical and watching for differences in the width of the bevels.  If it looks wrong, I’ll roll the ‘scope from side to side to get a better view.

BTW, I often use the ‘scope as a measuring tool by capturing an image and measuring features with the software.  For instance, my wife has a very expensive wrist watch and one of the very small pins attaching the band to the watch fell out and disappeared.  With the ‘scope I measured the hole diameter and found it to be 1.511 mm.  Figured that the 11 microns was probably measuring error and ordered some 1.5mm rods on Amazon, saving about $90 in repair costs.

1 user thanked author for this post.

CliffCurry

[Anonymous]

Im on a high end watch forum…those pin,s no matter what the watch is are very inexpensive, in fact most jewelers will put one in for free as a good will gesture. But I get your point..

Also I use the scope in the same context looking down at the apex and then going side to side to check for symmetry.

ON a side note, Ive been doing some research on high end Japanese knives, and their sharpening techniques, many true Japanese knives are sharpened asymmetrically, making them for a specific hand ( left hand held, and right hand held.)  Most of the 300 to 700 dollar knives are built with a right hand asymmetrical edge. if you want your 500 dollar knife to be left handed it will cost you another 20 dollars or so. ( I’m left handed , so this is a careful consideration ) .I’m looking to buy one of these knives, but at 500 to 700 dollars, I have to do a lot of homework first… BTW there are 1500 and 2000 dollar knives out there too.  I’m not sure I can appreciate a good quality knife but I’m going to see if a 500 to 700 dollar knife will be better than any of my 30 dollar knives.  I might find the right knife for 300 dollars too. there has to be more to a 500 dollar knife than snobbery. I’ve learned a few thing about Western design and Japanese design. I also know that China is not Japan, and places Like Ebay sell knock off Japanese knives that ” Look authentic ” but fail miserably in the quality and structure of the knife.. Even the handle of a western knife is different..  a WA  handle is not by design a HO handle, balance and weight are two other important factors… cladding is another.. good knives can rust, stainless is an ok steel  but has many faults. If we are talking edge quality with function, you can make any steel sharp, but how will it perform? carbons will always bee sharper and hold their retention, but they require much more attention to their use. Japanese chefs spend a lot of time learning how to use a Japanese steel knife.

The End..

Bill aka ET and also OCD

[tcmeyer]

Hmmm…

• Bill is 70.  I am 71.
• Bill is left-handed. I am left-handed.
• Bill calls himself ET.  I was an ET in the Navy.
• Bill has degrees in two disciplines: mechanical engineering and photography. I have a PE in two disciplines; mechanical and electrical engineering (sorry, no degree).
• Bill is OCD, and I am ADD (which is why I’ve no degree).
• We both have way more money in photographic equipment than we make use of.
• Bill has a corvette.  I always wanted a Corvette.

Kinda creeps you out, doesn’t it?

[tcmeyer]

[Author]

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