Spyderco Forums

A couple weeks ago I saw some random YouTube video about how sandpaper sharpening no longer makes sense. And the reason they were giving is you can get a pack of various grit diamond stones for $20 on amazon. And they last so much longer than sand paper.

I was a little skeptical but sure enough there are a ton of vendors on Amazon selling various assortments of grits for $18-$25. I got a pack that is 200, 400, 800, 1000, 1200. I won’t link to any particular Amazon item, you can pick which one fits your needs.

They work. They are not huge but plenty big for sharpening knives. They won’t be fully replacing sandpaper for me as I have sandpaper that goes up to 5k for sharpening razors. But these are convenient and compact. I’m sold.

I made this little block to hold them. It gives a little extra clearance and has some adhesive cork sheet under neath to keep it from slipping on the counter top. I used guitar fret wire as end stops but really you could glue toothpicks there and it would still work.

Thanks for the alert.

Don't the less expensive diamond stones go "bald" pretty quickly? That has been my experience. Maybe I just got unlucky.

I don't need them
I don't NOT need them.

I just ordered the 400, 600, and 1000 for $7.99.

Yeah they're decent and there are other brands or styles I've tried that also work pretty well. I will say that if you want a better sharpening experience, you need to mount a bare plate on wood or a thicker metal. If you mount these plates that have a thin foam backing, they flex and your edge will be more convex. Maybe that's ok with you but worth pointing out.

They will work a month or two till the diamonds fall off. With expensive diamonds, your paying for flatness, a good bond and consistant diamond size.
Just get a marble slab and some silicon carbide. I have under $16 in a set up like that I use to lap whet stones. Would sharpen the same as sand paper.

Freshly lapped natural stones cut really fast. Im not a diamond guy.

Just to clarify - these are not diamond stones, these are diamond plates.

ABX2011 wrote: ↑

Sun Dec 03, 2023 8:13 am

If you mount these plates that have a thin foam backing, they flex and your edge will be more convex. Maybe that's ok with you but worth pointing out.

You’d really have to be leaning into it for these to deflect if fully supported. Which you don’t want to do anyway.

I have this exact set of diamond plates off Amazon, figured why not they were cheap. They do in fact work but I question the grits being accurate, the 400 and 1200 are not much different while on my worksharp the 320 and 600 are noticeable different to feel and see. Either way they do work, just got them to play with and see if I want to actually spend the money on a good set in the future

I have some Worksharp free hand sharpening kit. Was like $80 and included three diamond plates. Been using it for 8 years with no issues. Took a chip out of Maxamet in less than 10 minutes recently.

Compared to one stone that can cost $80 by it self I would consider these fairly cheap but they work and last.

GT99 wrote: ↑

Tue Dec 05, 2023 1:52 pm

I have this exact set of diamond plates off Amazon, figured why not they were cheap. They do in fact work but I question the grits being accurate, the 400 and 1200 are not much different while on my worksharp the 320 and 600 are noticeable different to feel and see. Either way they do work, just got them to play with and see if I want to actually spend the money on a good set in the future

I agree and it’s been my experience as well. I bought one of the two sided plates awhile back to try and I forget the grits but they were far apart (like 250-800) and yet they felt almost the same.

https://www.harborfreight.com/4-sided-d ... 92867.html

These things are great for a cheap diamond stone. 200, 300, 400 and 600 grit sides. I've got 4 or 5 of them but still haven't worn out the first.

Minor update, I’ve sharpened all my kitchen knives with these plus a handful of folders. And I just reprofiled my Positron using the 200 grit plate. Hardly a longevity test for this kind of thing but they do seem to be holding up fine. Regarding the accuracy of the grits, I don’t see any indication that the grits are misleading. You can see the difference in edge finish as you work your way up.

I have struggled putting a usable edge on the positron for years. Mainly, I think, because the factory edge was so obtuse. I have a whole thread somewhere on my love/hate for this knife. It mostly I think stems from the obtuse bevel angle and thickness behind the edge. A “gents’ shiv” if you will.

I dropped the angle down to around 15 dps and it’s definitely cutting better. We’ll see how it holds up. I have a loupe somewhere and I should have looked at the edge before and after.

I'm not at all trying to rain on anyone's parade. But I was told by a reputable machinist that I worked with and fully trusted that "monocrystalline diamonds" were the type that were suitable for abrasives and for using with sharpening stones. I've been careful over the years to buy only stones made with that type of diamond and I've had good results overall.

Albeit I'm open minded and I might just give them a try. I've always liked trying different stuff anyway. The price on these cheaper diamond stones seems to be reasonable enough.

Just a sidebar. Two stones that I got from the 3M company have sure been excellent diamond stones to work with.

JD Spydo wrote: ↑

Tue Dec 26, 2023 11:34 pm

I'm not at all trying to rain on anyone's parade. But I was told by a reputable machinist that I worked with and fully trusted that "monocrystalline diamonds" were the type that were suitable for abrasives and for using with sharpening stones.

I’m no expert but from what I’ve read there seems to be trade offs. However, free handing knife edges is not remotely pushing the boundaries of diamond abrasives.