Sharpmaker Questions

D

dryflytrout

Joined
Jan 15, 2017
Messages
293
I have a couple questions about using a sharpmaker.

First, usually I can get a blade sharp with it. I was sharpening a friend's Kershaw in 8cr13mov the other day. I have the medium brown rods, fine white, and very fine white. I don't have diamond or CBN. I could get the one side sharp enough to catch my thumbnail but it skated going the other way. Like I got one side sharp but not the other. I started over about a half dozen times and while it improved, I expected to be able to do more. FWIW it was very dull when he left it with me. I've sharpened 1095, 440c, and even touched up m390 with the same set up and get much better results. I've sharpened other Kershaws and a Byrd in 8cr13mov in the past and ended with a edge that shaved hair from my arm. Any idea what the problem was?

Next, how much difference does only using the corner of the rod vs the corner and flat?
Finally, I follow the instructions that came with the sharpmaker but I've seen others suggest skipping some steps. Can you give me a brief description of the procedure you follow for using an SM.

Thanks.
 
The 'sharp on one side vs. skating on the other side' sounds, at the very least, like a burr that's leaning to one side. It'll catch on your thumbnail when the burr is leaning in that direction. But it will skate from the other side with the burr leaning away from your thumbnail.

It may also be that the burr created is the result of fully apexing from only one side, but not the other. It's possible the sharpening didn't get all the way to the apex on the 'dull' side. This can be further aggravated if the existing edge grind itself was very asymmetrical, i.e., much more obtuse (wider-angled) on one side than on the other - the more obtuse side will take much more work to reach the apex at the desired sharpening angle. Assuming you have a burr on the 'sharp' side, you'll then need to focus on setting a complete new bevel from the other side, until you have a burr that's leaning to the side opposite of where it was first seen.

You mentioned the edge was very dull when you started. If you're only using the brown & white ceramics, they'll take a very long time to set a new, clean & sharp edge on a previously very dull edge. So that raises the possibility and the likelihood the edge hasn't yet been fully apexed from both sides. This is a situation where coarser hones, like the diamond or cbn rods for the SM, could be much more useful.
 
I had a burr on each side. I finished with a few laps on a strop. I forgot to include that before. It's possible I didn't fully apex one side though. I'll try again when I see my friend and get his knife. I do have a diamond stone but not for the SM. I wanted to learn to freehand but I sucked at it and gave up. Maybe I can use that to make sure I fully apex it.
 
The corners are more aggressive than the flats. The edge has contact with just a small surface. So the pressure will be much higher. The flats sides of the rods will give a finer or smoother edge. Which is good for removing the burr.

You bought the UF rods already, but the coarse rods are more important. Because the Medium rods are very fine (finer than you might think about a stone called "medium"). Setting a new bevel, repairing nicks...that's not what the Medium rods are made for.

As the rods tend to load up quickly (especially when used dry) clean them regularly and thouroughly. Especially when you try to apex on the medium rods because you remove a lot of metal then.
A loaded rod will slow down your apexing still more.
 

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