Sharpmaker - Kershaw "Needs Work" Help - get to hair popping

[matt321]

... just consider all those "wasted" strokes as offering to the sharpening gods anyway.-Cliff

This is something I've wondered about before, i.e. the effect of the inability to hone at a precise angle either with a guided system or freehand.

If the angle for each stroke varies normally about the intended target, then you get a bell shaped curve reflecting the actual stroke angle and the number of occurrences. The mean of the distribution would be the target angle and the standard deviation would be a measure of the inaccuracy in hitting the desired target.

The distribution would be symmetrical and half of the strokes would be less than the target angle and half would be greater. So by this theory half the strokes are always wasted.

Guided systems would have a tighter distribution around the target, but still half the strokes are wasted according to the above logic. So when the Sharpmaker Rods are perfectly aligned, only half the strokes count. If the stones are biased to an angle less than the knife bevel, then even fewer than half would reach the edge.

 

[Cliff Stamp]

So by this theory half the strokes are always wasted.

Consider the metal removed with each stroke.

-Cliff

 

[Frank Hillary]

dextersp1

Have you got the UF white rods? I can only sharpen my Opinels to realy shave with the same steel using the UF rods. The standard white rods wont do it for me.

When sharpening shorter blades I hold the tops of the brown sticks together with a ruber band to reduce the angle by 5 degres. Then I go over to the white stones.

You may have to do some stroping after the stones if you really wanna that very sharp edge.

I also found that with some of my Opinels burs form on some part of the blade and not on others. I reckon that it was local overheating during grinding.

With Opinels I find that the stainless blades vary a bit in hardness. Some are harder than others. Guess its crappy quality control. If I get a realy good one it cuts like crazy but others are not uqite as good tho not bad.

Regards
Frank

 

[dextersp1]

Frank Hillary,
I don't have the UF rods but I might try stropping.

 

[Cliff Stamp]

Even the medium rods should be able to produce a fine shaving edge which should also push cut newsprint. In fact this is even possible with an x-coarse DMT hone or an 80 grit AO belt. The only reason the edge will not shave is that there is a burr remaining which needs to be removed.

Finer abrasives will naturally tend to form smaller burrs, but with proper sharpening techniques you can minimize burr formation even on steels which are prone to burrs. About the biggest sharpening challenge I have seen is on the CRK&T AUS-4A blades. If you can get them to form crisp edges then pretty much nothing is a problem any more.

-Cliff

 

[Frank Hillary]

Hi Cliff,

I take your point but how do you remove the bur created by a course stone without dulling the edge?

Regrads
Frank

 

[Cliff Stamp]

Burr removal does not really change depending on the grit of the edge. It is minimized by doing a prehoning step of removing all weakened metal, then using the smallest amount of force possible, so make sure the hones are clean, finally if absolutely necessary, elevate, hone, then reduce and reset the edge.

-Cliff

 

[Frank Hillary]

Hi Cliff

Thanks for your reply. Thats what I have been doing but sometimes it does not work for me and it should because I am a toolmaker.

Reagrds
Frank

 

[Cliff Stamp]

With some steels it is problematic, with the CRK&T's very soft AUS series blades it often took me 2-3 tries to get the edge crisp when I started working with them. If it fails to work then the best method is to clean the edge right off and start over rather than keep working with the burr.

-Cliff

 

[Frank Hillary]

Hi Cliff,

Thanks fro that. Ialso finsd some burs very dificult to remove. What I have done til now is to finish on a vry fine hone and then if I want acourse edge go back to a course stone.

Reagards
Frank

 

[Cliff Stamp]

That is another way, however in general I would take care in such cases as what tends to happen is a lot of deformation as the stones progress. I have noticed an extreme difference in edge retention from truely crisp to deformed edges, it is much greater than the typical difference in steels. Because the cheap steels like AUS4A are often left so soft they are difficult to sharpen to a true burr minimized edge and thus their edge retention in use is far lower than their actual optimal.

-Cliff