Spyderco Sharpmaker question: Re: Diamond stones

ziggy925

ziggy925

Joined
Oct 4, 2009
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105
I just got the diamond stones for my Sharpmaker. WOW, are they ever aggressive. I used a Sharpie to check my work and after not many swipes I had a very sharp "saw" edge on the blade. I got the diamond stones to save time profiling an edge, but because it's taking forever to smooth my new edges I'm wondering if it was worth it. Anybody else had this problem? Any suggestions?

Seems like no matter what method you use for sharpening there's always some "work" involved. :grumpy:

Update: I spent a little more time with the Sharpmaker. I'm still learning, so what I discovered is the diamond stone is doing a much better job of bringing the knife edge to an acute bevel. I always thought you needed a polished edge to slice through paper and such, but that's not the case, which would explain the videos of people sharpening knives on cinderblocks. I'm pretty happy now, but I think they should either make the diamond stone a little less course, or make a stone between the diamond and the medium.
 
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The good news is, the diamond rods are very aggressive, as compared to the stock ceramic rods.

The bad news is, the diamond rods are very aggressive, as compared to the stock ceramic rods.
;)

I say the above in good humor. But it sums up the troubles you're having, in attempting to use the ceramics to smooth out the very coarse scratch pattern from the diamond hones. The big gap in aggressiveness between the diamond and ceramics means the ceramics will take a long while to smooth those coarse scratches out. If it were me, I'd just use the medium and fine ceramics to gently clean up the burrs and other weakened steel coming off the diamond stage, and use the knife 'as is' for now. Assuming the new bevel geometry set by the diamond is good, the ceramics should do a great job in keeping the new edge cutting like a demon. Over time, if you keep using the medium (especially) and the fine ceramics to touch up the edge, the smoothing/polishing will eventually take care of itself.

You could, if you wanted to, use intermediate grits of wet/dry sandpaper wrapped around the rods to bridge the gap in aggressiveness. But I think the trouble to go through all that likely wouldn't gain you much in cutting performance anyway. There are also aftermarket vendors of other triangular stones which will 'fit' the Sharpmaker, in a fairly wide range of aluminum oxide grits (the 'Moldmaster' stones come to mind). But again, unless you REALLY want to pursue a more polished edge, you might not find it worth the extra expense and work.


David
 
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ziggy925 said:
(...)Update: I spent a little more time with the Sharpmaker. I'm still learning, so what I discovered is the diamond stone is doing a much better job of bringing the knife edge to an acute bevel. I always thought you needed a polished edge to slice through paper and such, but that's not the case, which would explain the videos of people sharpening knives on cinderblocks. I'm pretty happy now, but I think they should either make the diamond stone a little less course, or make a stone between the diamond and the medium.
Click to expand...

Just read your edit to your original post. Sounds like you're on the right track. :thumbup:


David
 
The diamond stones will also break in a bit after a few knives, and won't be as aggressive as they are new.
 
Thanks for the excellent replies. Yes, I figure once the new bevel is set all I'll need are the med and fine stones. I'm still amazed at how well the the rough, diamond edge cut. This is a great forum, and I'm learning that it really doesn't matter what method you use, if you understand the basics of sharpening any method should work for you. One day I hope to be able to sharpen a knife on a brick that shaves hair. (Sorry, I've never see a brick that can shave hair. I meant the knife.)
 
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cbwx34 said:
The diamond stones will also break in a bit after a few knives, and won't be as aggressive as they are new.
Click to expand...

True. While the ceramic rods will last indefinitely, the diamond rods have a cycle duty, depending on how aggressively you push them into the work.
 
I just purchased the diamond stones for my SM. I have several very dull kitchen knives I want to sharpen. My question is, how do I know how many strokes to do on the diamond stones before moving to the OEM coarse stones? I'm really new to sharpening. This 1st knife I'll be working on is dull enough that I can run the blade across my skin and not have a cut. It also fails the fingernail test, that's how dull it is to start.
 
this_is_nascar said:
I just purchased the diamond stones for my SM. I have several very dull kitchen knives I want to sharpen. My question is, how do I know how many strokes to do on the diamond stones before moving to the OEM coarse stones? I'm really new to sharpening. This 1st knife I'll be working on is dull enough that I can run the blade across my skin and not have a cut. It also fails the fingernail test, that's how dull it is to start.
Click to expand...

Don't rely too heavily on counting strokes alone. After every 3-5 passes on the rods, keep checking the edge with your fingernail, or with paper-cutting, or other similar 'tests' to see what progress you're making. If the edges are very blunt, you might start with 10-20 passes on each side of the blade, then abandon the stroke-counting beyond that, and just check for sharpness regularly as you work. On typical kitchen knives in simple stainless steels, it shouldn't take long to start seeing progress. Don't move to the ceramic rods until you can at least slice some paper relatively easily (expect some burring, which will snag a bit in the paper). You might start with your smallest/thinnest blade, to get a feel for how fast the process works. Light pressure rules; NO heavy grinding. ;)


David
 
Wow, OK, thanks. Prior to asking, I had already done at least 50-stokes to each side. I think it's getting better, but still won't cut paper. Maybe I'm doing something wrong.
 
this_is_nascar said:
Wow, OK, thanks. Prior to asking, I had already done at least 50-stokes to each side. I think it's getting better, but still won't cut paper. Maybe I'm doing something wrong.
Click to expand...

If anything, try going as feather-light with pressure as you can. With either the diamond or ceramics, using too much pressure will damage the edge more than it will sharpen it. More so, on the corners of the rods. The small contact area really focuses pressure, and will usually either roll or chip a fine edge on the ceramics. With simpler kitchen knives, it's usually the former (rolling). Diamond works so aggressively, that it'll both remove too much metal and damage the edge, if pressure is too heavy.

For regulating pressure on rod sharpeners, I always imagine I'm lightly brushing some dust off the surface of the rod, with the knife edge. Anything heavier than that will usually be counter-productive.


David
 
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