Sharp knives ...

[Ds J]

Good Evening Folks,

Just a few thoughts on the sharpness of knives:

- many (and maybe most?) knives are some form of dull

- some knives are sharp enough to get everyday kitchen chores done to some extent - most of these are still dull

- a dull knife has a shiny line on the cutting edge when viewing the cutting edge in light, or

- it has a ridge/burr where the cutting edge was bent; one easily feels it by pulling a nail over it from the spine of the blade towards the cutting edge, and over the cutting edge

- testing the sharpness of a knife by cutting through paper does not guarantee a sharp knife - it can be done with a fairly blunt blade

- a sharp knife will "bite" into a finger nail when scraped across the nail, ie: (VERY CAREFUL NOW!) put the cutting edge of the knife on your finger nail that the knife creates a a 90 degree angle with the finger; lightly scrape the edge of the knife across the finger nail while maintaining that angle; if it glides over the nail it is blunt; if it bites into the nail it is on the sharper side

- a knife that shaves arm hairs is fairly sharp

- a knife that slices easily through plastic (a cheap shopping bag suffices) is fairly sharp too

- a really sharp knife will chop through a human hair when the hair is held at only one end.   

[270win]

Good Evening Folks,

Just a few thoughts on the sharpness of knives:

- many (and maybe most?) knives are some form of dull

- some knives are sharp enough to get everyday kitchen chores done to some extent - most of these are still dull

- a dull knife has a shiny line on the cutting edge when viewing the cutting edge in light, or

- it has a ridge/burr where the cutting edge was bent; one easily feels it by pulling a nail over it from the spine of the blade towards the cutting edge, and over the cutting edge

- testing the sharpness of a knife by cutting through paper does not guarantee a sharp knife - it can be done with a fairly blunt blade

- a sharp knife will "bite" into a finger nail when scraped across the nail, ie: (VERY CAREFUL NOW!) put the cutting edge of the knife on your finger nail that the knife creates a a 90 degree angle with the finger; lightly scrape the edge of the knife across the finger nail while maintaining that angle; if it glides over the nail it is blunt; if it bites into the nail it is on the sharper side

- a knife that shaves arm hairs is fairly sharp

- a knife that slices easily through plastic (a cheap shopping bag suffices) is fairly sharp too

- a really sharp knife will chop through a human hair when the hair is held at only one end.   

The question is how best does one get your knife sharp, especially for us novice knife sharpeners.

[Ds J]

The question is how best does one get your knife sharp, especially for us novice knife sharpeners.

There is a saying along the line that one gets fast service, which is good, but not cheap. Or good service, but not fast, etc. One does not get cheap, and good, and fast.

Sharpening goes along similar lines.

It is about the combination of tools, technique and time. Good equipment tends to be expensive, technique takes practice, one cannot learn to sharpen quickly. Cheap equipment can work, but takes time and technique; etc.

More info sometime later.

[Treeman]

The question is how best does one get your knife sharp, especially for us novice knife sharpeners.

There is a saying along the line that one gets fast service, which is good, but not cheap. Or good service, but not fast, etc. One does not get cheap, and good, and fast.
Sharpening goes along similar lines.
It is about the combination of tools, technique and time. Good equipment tends to be expensive, technique takes practice, one cannot learn to sharpen quickly. Cheap equipment can work, but takes time and technique; etc.
More info sometime later.

*******************************************
Sharpening knives is far more complex than just putting a edge on a piece of metal, steel. My son like most boys is collecting knives, they are usually bought by the eye, or appeal to a boys sense of dangerous looking.
Most have no place of manufacture or brand name, some say Taiwan or China, there are a few that were gifted from the old guys that have America, Britain, Sweden and Switzerland on the blades.
The no name brands are usually impossible to sharpen pass a sharp edge and to a fine edge, the steel is just to soft and folds over or is just to soft to get that thin as to be sharp.
Then there are the Okapis of old they got a good edge, but only good, but the rusted overnight. The diving knifes did not rust, but that means they to soft to sharpen - stainless is soft.
The Opinal is a great steel and sharpens to a razer edge, but rusts so easily because of the high carbon content.The Puma blades are slightly less prone to rusting than the Opinal but cannot get the same fine edge.
The new Chinese steel is a remarkable, for R18 you can buy a blade that barely rusts, holds a edge to shave with and sharpens well at a 20Deg angle. Problem is they all have handles from the horror handle shop, cheap wood riveted on or plain plastic handles orange or yellow. The blades are usually razor blade thin as well.
So type of steel is important.

The angle of sharpening is also important,12 - 17 degrees being very fine sharp but not so durable and 23-24 degree edge good for hunting fishing. Ax's are at 25 degree +

For a quick sharpen the Warhog type sharpeners give satisfactory edges that last well enough, the key word is "ok-ish"
A oil stone is the old go to and can match any form of sharpening if user knows stone grades and knows howto use the stone.
For me, the Lansky is a lovely cheat method that makes a pro of any Tom, Dick or even Helin it just gives a brilliant edge. Read the instructions, they are worth reading.

[Ds J]

Some pointers regarding sharpening:

As Treeman says, good steel is a must. Most cheap knives are not worth the money because they cannot hold an edge. Hard steel holds an edge but takes longer to sharpen. Victorinox has one of the finest knife steels on the market. Buck has good steel, and Leatherman is very good too. On kitchen knives I prefer the well known Swiss and German brands like  Zwilling and Victorinox, Swedish brands are usually excellent- Frost comes to kind. For commercial purposes (where everyone abuses the company knife) I usually advise Brazilian or Spanish brands like Tramontina, Mundial or even Arcos. These are not everything that is available- there are just a few.

Belt sanders are ok for fast work but they tend to eat and/or burn the steel. Mechanical sharpeners like Pansky and Warthog take some time to get used to, however they are worth having in the house. Oil and water stones take time to learn proper technique. Pull through systems that work with ceramic or steel cross pieces can only destroy a knife - give them to skoonma, or use them on really bad knives.

I currently use sanding paper (400 - 800 grit) on a piece of soft leather, glued to a straight piece of wood. This results in a slightly rounded cutting edge, much like a katana, at an angle of roughly 17 degrees. I also polish the cutting edge on a strop after sharpening.

Last thing for now: it is more important to keep a knife sharp (regular honing) than to sharpen it.

[oafpatroll]

I currently use sanding paper (400 - 800 grit) on a piece of soft leather, glued to a straight piece of wood. This results in a slightly rounded cutting edge, much like a katana, at an angle of roughly 17 degrees. I also polish the cutting edge on a strop after sharpening.

^ This is what I learned from my cabinet maker great grandfather for sharpening woodworking tools and use for my knives. I glue wet and dry paper to a thick piece of bullet proof glass I got from a tip outside a bank branch that was being refurbed. For the strop I use and old thick leather belt that mysteriously shrunk some time back. I loop it over the burglar bar in my workshop window and have a different grade of polishing compound on each side. For quick touch ups at the kitchen counter I have had very good results with the 30 year old Lansky set I was given for a birthday present. For field use I have medium and fine Lansky triangular section ceramic sticks. No good for sharpening a blunt knife but a few strokes will get a dulled one back to shaving sharpness with gear that i can carry in a shirt pocket.   

[oafpatroll]

Of all of the chores I have I find sharpening to be the most 'meditative' if that's even a thing. 5 minutes in and my mind is a blank canvas.

[Ds J]

I currently use sanding paper (400 - 800 grit) on a piece of soft leather, glued to a straight piece of wood. This results in a slightly rounded cutting edge, much like a katana, at an angle of roughly 17 degrees. I also polish the cutting edge on a strop after sharpening.

^ This is what I learned from my cabinet maker great grandfather for sharpening woodworking tools and use for my knives. I glue wet and dry paper to a thick piece of bullet proof glass I got from a tip outside a bank branch that was being refurbed. For the strop I use and old thick leather belt that mysteriously shrunk some time back. I loop it over the burglar bar in my workshop window and have a different grade of polishing compound on each side. For quick touch ups at the kitchen counter I have had very good results with the 30 year old Lansky set I was given for a birthday present. For field use I have medium and fine Lansky triangular section ceramic sticks. No good for sharpening a blunt knife but a few strokes will get a dulled one back to shaving sharpness with gear that i can carry in a shirt pocket.   

Have you tried putting the strop on a flat surface as well, and using the same motion as with the sandpaper?

I use a cutthroat from time to time and the regular back-and-forth curved motion like in the movies rounds the cutting edge too much.

[oafpatroll]

Have you tried putting the strop on a flat surface as well, and using the same motion as with the sandpaper?

I use a cutthroat from time to time and the regular back-and-forth curved motion like in the movies rounds the cutting edge too much.

I haven't but will most certainly give it a try. There seems to be no end to what you can learn about something as apparently straightforward as sharpening.