What's wrong with my Sharpmaker technique?

[MacTech]

I've noticed something about my Sharpmaker technique that's....strange

i can get a PE knife bloody sharp (no pun intended) using the corners of the Sharpmaker hones, enough so that i can do that "slash cutting" thing you see Sal do on the video, they get shaving-sharp on the corners

but when i go to the flats, it almost seems like it's *dulling* the edge, after a session on the flats, i can't slash-cut paper, it actually hooks and drags, tearing the paper, if i run a couple passes down the corners again, i can slash cut paper again

i've watched the video a few times, and i'm working on already sharp knives, with the factory edge (specifically, my Native), and i want to maintain that edge at maximum sharpness, i keep the knife straight up and down and use slow, controlled passes with light pressure, just as specified in the video, the only way i depart from the video is i sharpen on one rod until i feel a burr forming, then i do a few passes down the opposite side to straighten out the burr/edge, i found that tends to set the edge more effectively than "20 passes per side, alternating"

are my knives too *short* for the flats, perhaps (the longest blade is the Endura 3, shortest are the Jester and Buck Metro), are the flats designed for knives with more blade area, like kitchen knives or fixed bladers like the Ka-Bar?

it doesn't seem logical that the flats should *dull* an already sharp blade....

what am i doing wrong?

 

[MacTech]

Actually, i just figured it out....

it turns out that sitting on my bed with the SM on my computer desk (yes, i have my computer next to my bed, wanna' make something of it? ) wasn't allowing me to keep as good a control on the angles as i liked...

i went downstairs to sharpen up some of our kitchen knives, and while i was at it, i took another stab (groan) at the Native on the flats, keeping the SM below waist-level was the trick, the Native is now scary-sharp again

...note to self, do not sit on bed and sharpen knives at computer desk, at the very least *stand up* at computer desk....

 

[IntheWoods]

Actually, i just figured it out....

it turns out that sitting on my bed with the SM on my computer desk (yes, i have my computer next to my bed, wanna' make something of it? ) wasn't allowing me to keep as good a control on the angles as i liked...

i went downstairs to sharpen up some of our kitchen knives, and while i was at it, i took another stab (groan) at the Native on the flats, keeping the SM below waist-level was the trick, the Native is now scary-sharp again

...note to self, do not sit on bed and sharpen knives at computer desk, at the very least *stand up* at computer desk....

Mac, one thing I've also noticed.

When you use the flats, especially on the white stones your polishing the edge more.

Which removes some of the irregularities in the edge. Irregularities and a saw edge that cuts paper best.

Sometimes I use just the corners for this reason. On some materials and with certain blade and steel types it cuts better. Following with light strokes on a strop can make that saw edge incredibly sharp. At least as sharp as any other method I've tried.

The same can be done with the flat sides of the stones, but it takes a very skilled hand, and tends to remove the saw edge.

 

[Psychopomp]

Different steels perform differently. The optimal level of sharpness for VG-10 is different than that of S30V. VG-10 takes a toothier, not as polished edge, which can feel sharper than a highly polished edge.

For my Endura, I finish with the Sharpmaker on the fine rod's corners and move onto a strop, skipping the flats of the fine rod. With S30V, I use the flats of the fine rod and then move onto a strop for a very, very sharp, highly polished edge. That edge doesn't feel as sharp by touch as the VG-10 edge, but it is.

I just ran my BM710 (154cm) across the Sharpmaker for the first time and it took a scary edge with the corners, but a little too rough. So the flats followed by a strop have left it shaving hairs above the skin.

You'll get different results with different steels. 440C seems to be ok (for me at least) with the corners and a strop, 420HC seems best with the flats and a strop, as does ATS-55.

As wonderful a tool as the Sharpmaker is, it isn't a replacement for good old fashioned freehand sharpening. For touch ups I've been using the little Gatco ceramic Tri-Ceps sharpener, but I can get just as fine an edge on my old benchstones as I can with the Sharpmaker. My carbon steel slipjoints and large fixed blades all get the freehand treatment, and I wouldn't have it any other way .

That said, I'd be lost without my Sharpmaker... I love that little thing.