Knife goes dull from 600 to 1500 grit?

MEJ

MEJ

Joined
Jul 24, 2011
Messages
1,283
I have just been sharpening my sage 1 free handed and when i drop down to a 600 grit sandpaper and then test the edge by brushing my thumb over it, i can feel a catchy burr but when i go up to 1500 it seems to go away and lose all its sharpness!

I need some serious sharpening advice?
 
Burrs can get very difficult to find and remove at higher grits, especially if you're doing it freehand. It's possible you still have a burr after your sharpening process. Try using a loaded strop after the 1500 grit sandpaper, it usually sorts out all of my burr problems.

Also, what backing do you use for your sandpaper?
 
I use a cheap wetstone that i dont like... It is pretty flat so i dont think thats the problem. I dont have a strop but i could look into getting one... Is there any other way to remove the bur or should i just get a strop?
 
You can remove the burr with the same sandpaper you used to sharpen it, but you must match the angle of the edge exactly, which is really difficult to do freehand. I prefer soft strops like leather because it conforms to the edge, and I don't have to mind the angle as much.

Also consider placing the 1500 (or finer) grit sandpaper on a mousepad and running the edge (trailing) of the knife on it 2-3 times lightly. Try to maintain the edge angle if not a little shallower. This could mimic the action of a strop and help with the burr. If it doesn't work apply a little more pressure, though I'm not sure if this may cause a burr to appear on the other side.
 
For me 600 to 1500 is to big of a jump. Try going to a 800 and/or a 1200 before the 1500.
 
MEJ said:
I have just been sharpening my sage 1 free handed and when i drop down to a 600 grit sandpaper and then test the edge by brushing my thumb over it, i can feel a catchy burr but when i go up to 1500 it seems to go away and lose all its sharpness!

I need some serious sharpening advice?
Click to expand...

The jump in grit is too much for the level of wear resistance the the steel has. When the steel has high wear resistance it requires close jumps in the grit progression.

Because of this the jump to a higher grit caused rounding of the "teeth" created by the lower grit. Thus a dull knife.
 
knifenut1013 said:
The jump in grit is too much for the level of wear resistance the the steel has. When the steel has high wear resistance it requires close jumps in the grit progression.

Because of this the jump to a higher grit caused rounding of the "teeth" created by the lower grit. Thus a dull knife.
Click to expand...

Alright that is something i would never have guessed... On the other hand this same process worked on my vg-10 delica.

Is that because vg-10 is a good deal softer than s30v
 
Mej - if your sage1 edge is still not cooperating, email plaincut@gmail.com - a good chance that my approach will work. Feel free to post your result+comments along with my reply suggestions.

I did a quick test. Started with a bm 940 s30v 30*inclusive slice tp clean shave-ready. Made a few slices into granite and it's tearing newsprint. Sharpened with wet&dry 600 then a big jump to 2000 (lol, I only have 2 grits), then stropped on bare leather. Slice newsprint cross grain smoothly & tp clean again but probably would get a burn doing dry shave. The whole test took less than 5 minutes, yup a bit longer than driving across the 520.
 
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