Sharpening Kitchen Knives

C

CattleMaster247

Active Member
Hey Guys,
So I have been sharpening a lot of knives lately for family and friends, and have been fortunate enough to work on some high end cutlery which are a true pleasure to sharpen. I sharpened 2 of my father's high end chef knives and 2 of his utility knives. Got them razor sharp, I then stropped the knives to finish. One thing he brought up is they were extremely sharp but had an issue with cutting a tomatoe. I believe that I probably progressed to far into my stone arsenal. I finished with a shapton glass 16k stone. At what point should I progress to with my stones for kitchen cutlery, and also to strop or not?
 
The angle of your sharpening is more likely the culprit. also a large Chef is not the best for Tomato's.

About a 5-7 inch slicer with a edge taken to about 15 degrees at 600 grit , Then stropped or buffed does the job great.

Laurence

www.rhinoknives.com
 
Hey Laurence,
Your quick replies and sound advice are much appreciated. If you don't mind I have a follow up question or 2 to add. Do you know of a good book or tutorial DVD that would illustrate/explain the different styles of knives and the correct finishing grits and bevels for the knifes. I am more interested in the kitchen cutlery than the folder's, tactical, hunting, etc, but any information is helpful. I had a post a month or so back, in regards to the difference in types of sharpening stones, in which I had a response from you that was very helpful. This question ties into my previous sharpening one's. Do the different types of sharpening stones, have any relationship to which to use for different style knives? Thank you again.
Dugan
 
Dugan,
A stone is a stone! You can sharpen all manner of blades and carbon or stainless on the same stone. Finer grits are for thinner knives to some degree &
A big thick bladed knife tends to have a courser finished edge.

Let me find my copy of a book that should help you quite a bit. Will post back when I can.

Laurence

www.rhinoknives.com/
 
Here ya go Dugan,
The Razor Edge Book of Sharpening. By John Juranitch.

Excellent, insightful and full of facts about sharpening and knives in general. A true sharpening Manual.

Laurence

www.rhinoknives.com
 
Laurence,
Your are the man, as always the information is much appreciated. I looked into the book you recommended will have it Tuesday, seems to be exactly what I was looking for. Also I took, my Kramer by Zwilling utility knife, and used your suggestion on the angle and grit, and now cutting tomatoes is effortless.
Dugan
 
Dugan,
I'm glad to help when I can, Many spend countless hours telling me, Go here, Read this, Try that, This is how I do it. till it soaked into my thick head.:biggrin:

The Giants before us in knife making led they way for many. The very least I can do is to return when I can what was so freely shared with me.

You will get a lot out of that book. I still refer to is often.

Laurence

www.rhinoknives.com/
 
You can also check youtube for Saltydog and knives. He's a chef and sharpens his to the point they'll fall into a tomato under their own weight.
 
Old thread but may still be useful.

Sounds like you've got too many steps in your sharpening progression. If you're going to 16k I'd guess you're using around 5 stones (400-1k-5k-8k-16k). The finer stones tend to provide less feedback and so make it easier to wobble the angle, especially with the narrow bevels on double beveled kitchen knives. The longer you spend sharpening on the stones the more any wobbles will compound as well. This may be the source of the tomato problems as the rounded edge won't break the skin. I'll assume you've got the basics down of ensuring you're at the edge before moving on to the next stone.

What are you stropping on? For kitchen knives a good rule of thumb is the harder the substrate the better as there is less chance that it will deform around the edge and round off the edge. I use thin leather glued to a board and balsa loaded with compound.

The quality of the steel and it's intended usage will dictate to an extent the type of edge. For typical mass produced knives a 1k edge that has been properly deburred is about as far as I would go. Deburring can be seen as key as any burr left will quickly fold leading to very rapid edge degradation.

For higher quality knives a 3k-5k edge is as far as I go for most double beveled knives for routine sharpening. When a knife is new I usually play around with angles and finishes to see what the knife will take, and what will be supported given the usage. When you mention high end which knives are you referring to?
 
You might also look at "An Edge In the Kitchen", which deals specifically with edge geometry,
sharpening and use of kitchen knives.
 
CattleMaster247 said:
One thing he brought up is they were extremely sharp but had an issue with cutting a tomatoe.
Click to expand...

The thing I don't understand about this idea, which I have heard many times, is how/why is sharpness defined in such a way that it is high but the knife can't cut a tomato? If the knife was sharpened in a way which would cut the tomato then would it make sense to say it was less sharp?

In regards to cutting a tomato, this should easily be possible with an extremely fine edge, in fact it should be easier at a high finish for example have a look at Salty's videos on very high finishes knives cutting tomatoes :

[video=youtube;QOQtOKhsC3w]http://www.youtube.com/watch?v=QOQtOKhsC3w[/video]

A critical issue in going to very high finishes, especially stropping is that the apex should not be rounded over which leads to an edge which slips/slides and won't cut a piece of rope for example. However if properly sharpened the cutting ability should steadily increase. As a simple experiment, take a piece of 3/8" hemp (or leather or whatever), sharpen it with a x-coarse dmt (or similar) and make a cut in say a 2" draw and record the force. Now repeat this with a finer finish and the force will decrease. The force keeps decreasing and at some point the knife will cut without a draw.

However before the conclusion is jumped to that high polishes are ideal and that everything should be high polished, there is often a large increase in edge retention with most coarse finishes :

-http://www.cliffstamp.com/knives/forum/read.php?3,37143

 
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