Sharpening Questions

B

BuckMcStrokes

Joined
Jan 12, 2014
Messages
3
So.... I am just really getting into sharpening and blade work.... I have sharpened my knife several times and it is sharp, but I tried something new and got some 1500, 2000, 3000 wet dry and a board. started with my diamond stone then arkansas stone, both smiths, then went to polishing with the wet dry. It came to mirror edge but as I went on it seemed to not feel as sharp... It cuts well but stopped catching hair as I went on... anyone have any ideas?
 
Do the paper test and see how it does. You may have over sharpened the knife.

"Catching hair".... you mean cutting hair?

Really sharp knives are difficult to check rubbing your finger across the blade as I typically do. A slightly toothly edge actually feels sharper to my hand, but I know that the the polished edge if done properly will be much like a razor blade.
 
It wasnt shaving but you could feel in cutting I guess lol.... I cut some paper that was pretty thick (package for one of the stones)... it took some pressure but cut straight. I feels really smooth and i can run my finger on it with cutting it but I dont do it hard... I think i had it around 18* i would figure it would be pretty damn sharp...
 
Sharp is a fully apexed edge at any grit. Did you use the sand paper on a hard surface or soft?
 
I used it ona hard rubber... I tried it today on different paper but its not cutting.... I think i ended up removing to much edge and made more of a wedge... I am going to try again when I get off tonight and see what I can do.
 
The finer the abrasive the more exacting YOU must be. When you make mistakes at a very fine level you easily round and blunt the edge, it will still feel sharp but as you have noticed it will loose some of its finer cutting ability.

Try using edge trailing strokes only on the paper.
 
Sandpaper needs to be absolutely flat, make sure of that first before you worry too much about technique, I do agree with edge trailing strokes though.
 
I second making sure the wet/dry is flat. Wrap is as tight as possible around something like a piece of glass or steel plate, your Arkansas would make a good base as well. anything with give will compound the possibility of softening the edge at higher grit. Avoid "hunting" for better feedback by elevating the spine - trust your angle and give it time to grind down to the finer abrasive - feedback will increase as you get on the apex.
Another trick of mine is to lightly lower the spine every few passes to recalibrate on the shoulder for a half stroke. Working the bevel should feel relatively quiet until you reach the new apex. Hitting the shoulder or apex will increase felt feedback and you can use that to get a feel for where you are on the bevel, how rounded or flat it currently is.

If the paper is tight enough you can use a back and forth stroke, same as a solid benchstone as long as your angle control is reasonably solid. Becomes more challenging as the abrasive gets smaller but will certainly keep you honest.

This video is sandpaper on a Washboard, but is comparable to wrapping the paper around a stone or similar.

https://www.youtube.com/watch?v=YxdzCV-JkMc
 
The paper + hard backing + trailing strokes will work a LOT better if the paper is fully flush (ideally stuck/glued) to the hard backing. Anything that works to keep the paper from curling up or lifting or moving under the blade is beneficial. I've used some temporary adhesive (DAP Weldwood Multipurpose Spray Adhesive; see below) to coat the back of the paper, let it dry to a tacky feeling, then press it to the hard backing (hardwood/plywood or glass works very well; the smoother, the better). Then use trailing strokes as recommended. This is my preferred setup for stropping as well, with plain paper + compound on the hard backing. Very, very crisp edges when done this way. I recommend the temporary adhesive, because this is much easier to peel up and replace the paper when necessary. The adhesive stays relatively tacky for quite some time, and I haven't needed to re-spray each time. Just peel old paper off, and re-stick a new sheet.

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David
 
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