trouble sharpening benchmade S30v on sharpmaker

[mannysdad]

Has anyone else experienced trouble sharpening benchmade knives with S30v steel on the standard sharpmaker with med and fine rods? Will the diamond rods help with this situation? What are the reasons this is a problem? Thanks for your help, MD.

[JD Spydo]

The brand of knife has very little to do with it. Someone else's heat treatment can't be too far off from what Spyderco does. I'm saying you are probably just doing something fundamentally wrong and if you watch the 204 Sharpmaker instructional video I'm sure you can remedy the problem.

Also another problem I have run into with Sharpmakers are keeping the stones good and clean. Ceramic stones tend to load up badlky even after doing 2 or 3 blades. I usually clean my stones even after every 2 sharpenings.

Another tip that might help you is to somehow clamp the Sharpmaker on the table securely That way you have both hands free which helps you to concentrate on keeping your you blade straight up and down in orderr to get proper honing.

[1623]

As JD mentioned, you may just need to adjust your technique with that particular knife. You could also try the Sharpie method of coloring the edge to help you make those adjustments...it really provides an excellent visual as to what's happening on the stones.

[bh49]

Has anyone else experienced trouble sharpening benchmade knives with S30v steel on the standard sharpmaker with med and fine rods? Will the diamond rods help with this situation? What are the reasons this is a problem? Thanks for your help, MD.

There is a good chance that you are not sharpening, but reprofiling. meaning that you are removing steel from shoulders instead of edge. From my experience with BM, they sharpen their knives to more obtuse angle than Spydercos. So two questions for you? What settings on SM you are using 30 or 40 degrees? And second, did you color the edge to see, where steel is getting removed. This is the first thing you need to do. Keep in the mind that standard sharpmaker is a great tool to maintain the edge. If you reprofiling, you need coarse rods. Diamond or CBN.

[Ankerson]

Benchmade typically uses a rather steep edge geometry to keep the bevel small so it will typically be 20 degrees per side +, more in the 25 Degrees per side range or better from what I have seen.

[mannysdad]

I checked the edge with the sharpie and the removal appears to be basically perfect for the sharpmaker. I can get the knife considerably sharper than "factory" but no where near other blades like 8cr13mov and vg-10. I'm trying to get a bm grizzly creek scarry sharp. I'm still wondering if starting with those dia. rods would help. That Sv30 is some hard stuff!!!

[Cliff Stamp]

I checked the edge with the sharpie and the removal appears to be basically perfect for the sharpmaker.

The problem is that you can't see below a certain level, for me it is about 20 microns or 1/1000". At that point to my eyes it would look like all marker is removed but that small amount is still there. Many manufacturers ship their knives with a very heavy micro-bevel, once this wears and you try to sharpen the knife at the setting on the Sharpmaker you have to grind that micro-bevel off before you hit the apex. There is a very easy way to check if this is happening or not :

-take the knife, and using just the weight of it, draw it across the medium rod like you are trying to saw it in half

This should leave a small flat on the edge and if you rotate the knife (edge up) in light you should be able to see the light reflecting from the very point of the edge (apex) that has that flat.

-go back to the medium rods at 20 degrees and make just 5 passes on each side

Is there a significant difference in the light reflecting? If there isn't, then that is the problem, the bevel doesn't actually go right to a point yet, there is no apex formed and you have to do a lot of grinding to make it happen. The good thing is that once you do this the first time you don't have to do it again, subsequent sharpenings are faster.

Yes, the diamond/cbn rods speed up the first sharpening over the mediums by around ~10:1 .

[tvenuto]

I like the light trick Cliff mentioned (I almost typed "Cliff's light trick" but then remembered that it was probably invented by Murray Carter, glad I caught this grievous mistake). Also I can strongly recommend the picking up a pair of diamond rods. Sharpening is fun, but reprofiling is just time consuming, and there's no reason not to speed it up. I haven't used the CBN rods, but I'm sure those work great as well.

[adancingmonkey]

I can tell you I've been trying to reprofile my sage on the 30 degree side using the CBN rods and it has been very slow going. Using a sharpie along the edge on both sides I've been working one side for a very long time trying to get the last bit of sharpie along the edge. Maybe I'm doing something wrong but it seems pretty straight forward to keep the blade straight up and down and draw it along the stones until no sharpie is left. I'm at over 1000 passes but as I get closer to the edge it seems I have to make more and more passes to see any progress.

[Wanimator]

It's because of Benchmades obtuse and shallow microbevel (Not really obtuse, it's acute by angle definition but it's obtuse in the sense that it's quite thick). In fact, Benchmade's S30v according to most sources is softer than Spyderco's and the few other brands that use it. (I don't think it's Gerber bad though).

[Cliff Stamp]

... but as I get closer to the edge it seems I have to make more and more passes to see any progress.

That is as expected as you are having to grind over a larger area as you make progress. Make sure the rods are clean and that you use some kind of cutting fluid/lubricant.

I like the light trick Cliff mentioned (I almost typed "Cliff's light trick" but then remembered that it was probably invented by Murray Carter, glad I caught this grievous mistake).

Ha, you are a funny guy tvenuto, I'll kill you last. I am pretty sure I have the first video on that though, so using forum logic everyone also should never make another video on it and just note mine whenever it comes up as it is a perfect idea and can never be improved on or a more clear demonstration done in any way or to make another point.

I believe I first read about that from Wayne Goddard. Now most people know if you can see the apex it isn't sharp but Goddard was the first person I think I read who noted you could use that during sharpening and that as you removed light from the edge is was getting sharper. Now this seems like a trivial idea as if you can see the light then it is dull then it doesn't take much of a leap to know when you have removed it then it is approaching sharp -but- using it as a technique is rare, almost all of the problems noted here could be resolved with it.

As a side note, Goddard was definitely the first person I read who argued burr removal on a stone at elevated angles, Clark later made the same argument and was much more specific and note to make the angle very large (2-3X). I keep meaning to write up a basic article on how I sharpen and attribute the method accordingly.

[opusxpn]

Reprofile at 30 on benchstone and then add a 40 microbevel had same trouble with knife

[bh49]

The problem is that you can't see below a certain level, for me it is about 20 microns or 1/1000".

Cliff,
you must have really great eye vision. Not many even people of your age can see .001". For these who cannot (like me) there is always an 10x-15x eye loupe and old method to create a burr on one side, than on the second and carefully cut it.

[twinboysdad]

My Sharpmaker thinks Benchmades suck...

[mannysdad]

go figure; I buy a $200.00 grizzly creek bm that basically was dull from the factory and just got an $80.00 mini griptilian that was razor sharp!

[Cliff Stamp]

[
you must have really great eye vision

I keep my glasses updated every year, without them I can see the knife, maybe.

[adancingmonkey]

... but as I get closer to the edge it seems I have to make more and more passes to see any progress.

That is as expected as you are having to grind over a larger area as you make progress. Make sure the rods are clean and that you use some kind of cutting fluid/lubricant.

I haven't cleaned the rods lately since I started maybe I'll do that. I did notice that when I was using them wet with water I did seem to make faster progress.

I have heard that s30v can be frustrating to sharpen compared to say vg10 so I'm not surprised. I'm glad I have the CBN rods though makes a difference. Also glad I only have to do one side of the knife since the sharpie was removed completely from the other side.

[can't freehand]

if the rods are ceramic then they can only sharpen the steel surrounding the vanadium. Ceramic can't cut vanadium, and so at higher grits ceramic can't sharpen S30V, "higher grit" being 2-4 microns. For that you will need something like DMT's Extra-Extra fine diamond stone, or the 1 micron Diapaste, or even more radical stuff.

Honestly though, I've found S30V to resist sharpening on ceramic, crystolon, and India, FAR more than 154cm. For that reason I've gone full diamond with S30V, regardless of grit amount.

[bh49]

[
you must have really great eye vision

I keep my glasses updated every year, without them I can see the knife, maybe.

I keep my glasses updated as well. Still cannot do this, but I know couple people, 20 + years younger than me who can see .001" without glasses. May be hard to believe, but I tested them few times.

[Cliff Stamp]

My vision was always average, but most of the males in my family have better than 20/10 vision. They are descendent's of fisherman and keen eyesight is prised there for many reasons.