How Sharp Can a Knife Be?

[IamMatt]

I had to cut up some cardboard boxes and the CRKT Point Guard I had in my pocket was just not doing it, so I thought I would try some of my other knives. Third one was an Al Mar Eagle. It went through the cardboard like it was butter. Same with an Al Mar Hawk. A Sebenza was in fairly close second place.

I had a knifemaker at a show sharpen the Point Guard on his wheel, and it is an improvement, but still nowhere near the Al Mars.

So my comments are:

1) Al Mar blades kick @$$.
2) Reeve blades are damn good too.

And my questions are:

1) Is there something unique about the Al Mar blade geometry or some factor that makes them so much sharper than many other knives?

2) Should a maker/bladesmith be able to but an edge as sharp as my Al Mars on my CRKT or similar knives?

3) Do some makers or manufacturers deliberately make their blades considerably less sharp than they could be, and if so, why? Is there a reason to have your blade less sharp than it could be?

Thanks. Matt

 

[Tightwad]

To me sharpness is a collectionof several factors with none being
more important than the other.

1st. is blade shape which determins how the cutting edge will be presented
to the work.

2nd is blade grind which determins the ease with a which a blade will
pass through the work.

3rd is blade material which determins how much and how long an edge
the blade will have / hold in the work.

4th is handle shape which detrimins the effetiveness of the force applied
to the blade along with blade control.

5th is edge angle which determins the matter seperation ability of the blade.

This combination ,as an example, is why the Al mar out cuts the other
knives mentioned. It combines all of the features in a more effective way
than many other knives. I've always found that the best cutting knives
seldom are "unusual" in both blade design and material. Old well proven
designs outshine newer hi tech designs everytime in actual use.

As to the sharpest knife I've every seen.... it was made from obsidian glass
with an edge you could not see . I would cut well before the main body
of the blade touched the work.

 

[Roger Blake]

The Al Mar's have a thinner blade that is flat ground. The thin blade makes a big difference. I noticed long ago that my knives with a thinner blade cut better. The thinner bevel angles also help alot but I would not change them on the Al Mar. The AUS-8 Al Mar uses takes a great edge too. My Al Mars, I had two, started to develop vertical play after a year of use.

I notice that older non tactical type knives out cut the tacticals which I chalk up to the thicker blades on tacticals.

 

[Alidisaster]

<b>Sharpness</b> is relative to what you are cutting. I shave with a straight razor - and in the conventional sharpening test (shaving hair from arm), it doesn't do as well as my Frost Sloyd whittling knife! But the Frost knife is useless for shaving a 'whet' beard. My Swiss Army Mariner knife has a serrated blade that seems blunt under most sharpening tests - but cuts rope better than the Frost knife.

If you are comparing polished edges - try the barber's test. Wet a thumbnail and draw (no pressure) the edge across your thumbnail. Repeat this. On the second attempt, a truly sharp polished edge will 'drag'. More drag - sharper edge. The reason you do it twice is to 'knock off' any micro-wire-edge - which shouldn't be there on a polished blade anyway.

Incidentally, my Frost knife cuts wood better than any other steel I've used. It has a saber grind, >1/8" blade with the wickedest point I've ever seen - great for fine detail carving in seasoned hardwoods. I've been using it on seasoned holly and it cuts with the most fantastic 'shrrrk' sound. This has the added benefit of putting people off from picking it up and fiddling with it.