Angles to use? (sharpening questions)

drrickso

drrickso

Joined
Nov 5, 2014
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I "think" the factory edges on all of my knives are all more than 30 degrees inclusive, and was wondering if I should just aim to put a 30 degree incl on all of my blades, or if some will call for > or < 30.

Will blade steel make a difference on what angle I should use? If so, is there a chart somewhere that gives guidelines on what types of edges could be achieved per steel?

Should I just follow the factory angles (I'd like to make them sharper than that, so I hope not)?

What's considered the lowest I can get away with without compromising the integrity of the blades?

Do I need to do combinations of angles to get the best results (ex. start with 30, end with 40)?

Thanks!
 
drrickso said:
I "think" the factory edges on all of my knives are all more than 30 degrees inclusive, and was wondering if I should just aim to put a 30 degree incl on all of my blades, or if some will call for > or < 30.

Will blade steel make a difference on what angle I should use? If so, is there a chart somewhere that gives guidelines on what types of edges could be achieved per steel?

Should I just follow the factory angles (I'd like to make them sharper than that, so I hope not)?

What's considered the lowest I can get away with without compromising the integrity of the blades?

Do I need to do combinations of angles to get the best results (ex. start with 30, end with 40)?

Thanks!
Click to expand...

In my experience, anything between 25 and 30 inclusive is a very good average on just about any steel. Depending on use and steel type, one could run the inclusive much more acute, but on common cutlery steel, anything in the low 20s and lower will begin to show a lack of lateral strength (though will cut very well as long as done with care). A good deal of this is also going to depend on the thickness behind the edge, but in general.

In my experience, using angles much above 30 inclusive does not improve durability to any appreciable degree, even on machete and hatchet, and will begin to impede good cutting characteristics.
 
awesome- thank you! I'll start to get everything down to 30 incl, and go from there.
 
HeavyHanded said:
In my experience, anything between 25 and 30 inclusive is a very good average on just about any steel. Depending on use and steel type, one could run the inclusive much more acute, but on common cutlery steel, anything in the low 20s and lower will begin to show a lack of lateral strength (though will cut very well as long as done with care). A good deal of this is also going to depend on the thickness behind the edge, but in general.

In my experience, using angles much above 30 inclusive does not improve durability to any appreciable degree, even on machete and hatchet, and will begin to impede good cutting characteristics.
Click to expand...


I'll add to this that once you have that 25-30 inclusive edge, a dull apex can quickly be restored to working-sharpness by sweeping the hone 1-2x at a slight increase in angle to realign the edge or form a microbevel. A similar effect is obtained via stropping, namely a 25-30 inclusive bevel-angle with an apex (and I mean <0.01" at the edge) that is actually closer to 40 inclusive. You wouldn't want to persist too long in restoring the edge by simply raising the angle, but it can keep your knife cutting well until such time as you can re-establish the more acute bevel with appropriate equipment.

Alternatively, first make sure that the knife you have is the appropriate thickness (or thinness) behind the edge-bevel for your use. If your knife experiences very little lateral or impact stress yet is ~0.030" at the edge-shoulders, it is too thick. Not only is cutting-efficiency impeded, the bevel is also so wide (~0.06" if sharpened at 15-dps) that it requires much more effort to restore the edge as it dulls or to bring the angle down to a more desirable cutting geometry. If the knife were thinned by half to 0.015" at the shoulders (i.e. "behind the edge"), this may still be stronger than is needed (most damage occurs within the edge-bevel in normal use) and the edge-bevel is only ~0.03" wide, much quicker to restore.
 
I tend to go more for durability in my knives and use the most obtuse edge that still cuts efficiently. It depends a lot on the steel and the thickness of the blade. Generally i only go below 30 inclusive on my kitchen knives.
 
For performance, the thickness behind the very edge is decisive, not the very edge. One of my best performing kitchen knives is a very thin, soft carbon Nogent with an inclusive edge of some 45 degree -- due to a one side microbevel of some 30 degree. By the way, I sharpen my carbon Opinel in the same way but that one is a bit thicker behind the edge.
 
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