How to find the original edge angle on a knife

[Brosenfeld86]

I was wondering how to find the original edge angle before beginning the sharpening process? Is it necessary on all knives? or does the 20 degree angle work for most knives other than single bevel knives? Thanks!

[Rhino]

There is an angle guide in that Tormek Anglemaster.  It is all those slots on the side of the rectangular card part of the Anglemaster.

Or you can buy an Angle Guide.

Of course, if the knife has been sharpened too much, the original angle would have been ground off so you will never know by measuring.  Maybe there is an area of the blade that has not been ground too much, like near the handle.

Assuming you still have enough of the original angle, you can use the market method to set the stone.  But this is not the answer to the original question - which is determining the angle.  But, once you set the stone and you know the contact points, the Anglemaster should give you an idea of the angle.

I wouldn't worry too much.  I saw a video of how some name brand knives are made.  The final sharpening was done freehand so there will be some descrepency in angle from blade to blade even with the same manufacturer if they are freehanding the final angle.

[Brosenfeld86]

Thanks for the response! Should I find the original angle of every knife I sharpen before sharpening it? I've been sharpening most kitchen cutlery at 20 degrees, should I first find the angle it's already at? Thanks again!

[Herman Trivilino]

I don't think it's all that important that the angel match the original.  It's difficult, anyway, to determine the original angle on a thin knife.

As we've discussed here before, one of the advantages of having a Tormek is the ability to experiment with different angles.  I'm surprised by how much difference I get in performance with just a small change in the angle.

The angle that works best depends on how you use the knife, and also on the features of the steel itself.  Different edge angles will affect not only how well the knife performs but also on well the edge holds up.

[Mike Fairleigh]

If you're also talking about edges outside of the kitchen, it also pays to gain an understanding of various types of grinds.  Each has strengths & weaknesses for different jobs.

You could put a "20 degree" edge on 5 knives, but if each one is ground differently as follows, they will excel at different jobs more than the others.

[mike40]

Interesting question and answers. All helpful info.

[grepper]

If you wish to maintain the same angle that the knife currently has, I'd use the marker method as Rhino suggested.  It's quick, easy, and accurate.  BTW, if you slop over onto the side of the blade with the marker, a little alcohol will remove it.

If it's your own knife, how's it been performing?  Does it dull too quickly?  Maybe you don't care because resharpening is only a Tormek away.  Or, maybe you may wish to try a more blunt angle.  Not filleting to your satisfaction?  Maybe a thinner bevel. 

There are some general recommendations:
http://www.sharpeningsupplies.com/Tips-for-Selecting-the-Right-Bevel-Angle-W44C116.aspx
http://www.sharpeningsupplies.com/Detailed-Discussion-on-Knife-Sharpening-Angles-W28C60.aspx

Sharpen to 20 degrees, and then hack up a bunch of carrots, potatoes and some over ripe tomatoes with a tough skin.  Or maybe a plum or some spinach and some rosemary.  A kumquat?  How'd it do?  Now try the same thing at 15 degrees. 

Of course you would probably not want to sharpen a cleaver to 15 degrees and then start whacking and hacking on a chicken.  It would dull quickly with such a thin bevel.

If it's your own knife, then you can make it be whatever you like the best. 

[Rhino]

When I was a kid, we cooked just about every meal from raw material.  Sometimes we butchered a chicken and butterfly it - cutting to the left and right of the backbone and flattening it.  Fish heads have to be cut off and descaled.  The butcher leave bone and fat on the meat and it had to be trimmed.  The family was big and everyone was growing and there are aunts and uncles who help with cooking.  Ground beef can be made in a jiffy by chopping. 

Knives were sharpened regularly and put to hard use 3 times a day at least.

It was not done for fun.  We don't hate it, but it was just another chore.  We had just one knife for everything.  and a few small paring knives.  That's it.  You wait your turn when cooking - until the other person finish with the knife.

Under that circumstance, a more robust angle would eliminate multiple sharpening.

Now I am older, I buy boneless this and that and the kitchen knives rarely sees a bone.  I don't take apart chickens.  So I enjoy a sharper and more delicate blade.  Also, I have multiple knives for different situations.  I have three chefs knives, one cleaver, one axe, filet knives, a tin snip for really cutting something hard.  I sharpen each to different angles depending on how I use it.  I only cook for fun.  If I am tired, I go out and eat something cheap.

Now I use sharper and more delicate angles on most knives saving the axe and tin snips for big jobs that hardly ever comes.

What the others posters say is really true.  There is no right angle.  It depends on your personal usage, how much fun you are getting from a sharp knife, how much use, how many knives you have.  Have fun and experiment.  That's the luxury of owning a Tormek.

[Herman Trivilino]

Here's a cross-section of another common type of kitchen knife.  For example the Victorinox, which is a very thin knife.  These knives are so thin I can't see the bevel with the naked eye so I can't use the Angle Master gauge or the marker method.  I haven't had to sharpen mine yet but when I do I think I'll do a 15^o bevel on each side, for an edge angle of 30^o.

Someone, I think Ken, commented that he'd heard that good knives have bolsters.  I wonder if this is a truism from the older days when we didn't have the modern types of steel alloys and surface treatments necessary to make a good knife that was also really thin.

Thin knives are nice in the kitchen as they cut through stuff easier, and of course the steel must be rigid enough to withstand the cutting and chopping of veggies.

[Rhino]

Speaking of original grind angles, I am not impressed with my new Sabatier chef's knife.  The sharp edge was not a smooth curve from the factory.  There were some straighter curves connected by sharper curves.  I am going to regrind that knife a little bit when I get the chance.

The high carbon (capable of rusting) metal was beautiful though.  Very sharp and easily honed.  I would buy it again.  Plan to buy a few more next year.

[jmforge]

If you're also talking about edges outside of the kitchen, it also pays to gain an understanding of various types of grinds.  Each has strengths & weaknesses for different jobs.

You could put a "20 degree" edge on 5 knives, but if each one is ground differently as follows, they will excel at different jobs more than the others.

That is really not a very accurate representation of a full height convex grind. More like a full height flat grind with a VERY thick convex edge. 

[Mike Fairleigh]

Yes.  Not my art but I think it illustrates the differences in edge geometry and makes it easy to understand how one would work better than another for specific tasks.