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Spyderco Ultra Fine - problems with Vandium steels?

Posted by Erik 
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Spyderco Ultra Fine - problems with Vandium steels?
November 25, 2016 10:50AM
Background: I ordered a Spyderco Fine stone from Amazon's warehouse, 2nd hand, and ended up getting an Ultra Fine in the mail instead. I figured I might as well try it out since I already have this Ultra Fine and decide whether or not to send it back.

The reason I ordered the Fine is because I was having trouble, great trouble sharpening S30V on the Sharpmaker's Fine rods and thought that more surface area with the ceramic would make it easier, and I naturally prefer stones anyway. So I traded the sharpmaker in for this stone. However, I have the same problems with this Ultra Fine that I had with the Fine: its very difficult to sharpen Vandium steels with this extremely high grit ceramic.

Some clarification: I can sharpen vanadium steels like s90v and s110v with this Ultra Fine at their *factory* bevels, whose angles are nice and straight. Even so, it takes far longer to sharpen those steels at their factory edge than VG-10 at the factory edge. Now, I say this because I think concavity on reprofiled edges might be interfering with a vanadium edge that is already very hard to sharpen. I have a military S30V that I've reprofiled multiple times free-handed, and so the edge bevel is inherently concave; the bevel's angles are not uniform like the factory edge, they are slightly rounded. I suspected that this irregularity was making it that much harder to properly grind the vanadium steels.

So I tried an equally concave 154-cm edge and I was able to sharpen it easily. I then sharpened a concave VG-10 edge easily, and then I sharpened a concave ZDP-189 Endura easily. I then tried some Dozier D2 (1% Vanadium) and it's sharpness consistently improved with each pass but noticeably slower than even ZDP-189, strangely. Then I tried to switch the edge angle on the S30V military by raising it considerably to make sure that I was grinding against the apex and not merely sloping along the concavity, and I was not able to achieve a suitable level of sharpeness. So I went back to the medium ceramic, reground the Fine's mistakes off the edge, got the S30V very sharp with the medium ceramic, went back to the Ultra Fine. Now I went as low as possible while estimating that I was still running the apex parallel to the abrasive. The results were mixed; the level of sharpness was held constant and refined with the Ultra Fine, but not improved. It actually shaved hair less easily than with the medium.

Conclusion: all the non-vanadium steels worked splendidly on the Ultra Fine. The factory bevel S90V and S110V knives (they're brand new) achieved a final sharpness comparable to the factory VG-10, but took substantially longer, even dramatically longer than the factory bevel VG-10 knife (unused Delica). The ZDP-189 took longer to sharpen than the 154-cm, but easily matched 154-cm in final sharpness. Tellingly, I found the Dozier D2 (slightly concave) to be harder to sharpen than even ZDP-189. Lastly, the S30V military is a complete mystery. On the one hand, the S90V and S110V sharpen surely at their factory bevels and they have a much, much higher vanadium content, but I have no problem sharpening non-vanadium steels with a concave edge and a 1% vanadium concave edge with the Ultra Fine.

My question: is concavity really the problem if I can sharpen concave non-vanadium steels just fine? Even D2 has 1% vanadium. Or is there a certain amount of vanadium content at which edge concavity severely multiplies the required precision of a pass on an Ultra Fine stone in order to properly sharpen the edge? Has anyone had this problem?

I don't want to return the stone because I really like the edge I'm getting on non-vanadium steels and D2, but I have spent hours working this S30V and I simply cannot get it as sharp as I want, and I want to be able to use vanadium steels. I find it hard to believe the S30V is the problem because I can get it very sharp just fine on coarser abrasives. I have sat here and tried as hard as possible to maintain angle consistency, with much greater caution than the treatment I gave VG-10, which gave me a seriously sharp edge, and the S30V is just not complying. I don't know what to do.
Re: Spyderco Ultra Fine - problems with Vandium steels?
November 27, 2016 03:43PM
Erik, a few questions :

-are you jumping from the medium to the UF stone

-when you say you are sharping the concave edge, do you mean you are flattening it or just attempting to follow the curvature

-are you using the stones dry, are you cleaning them

-how much force are you using (just estimate it, nothing fancy)
Re: Spyderco Ultra Fine - problems with Vandium steels?
November 29, 2016 06:05AM
I am indeed jumping from a medium ceramic to the ultra fine ceramic

I am using the stones dry

I'm using pretty light force on the ultra fine but not so light that only the weight of the knife is being applied

as for the sharpening the concavity: initially I tried to "flatten" the edge/bevel's angles as much as I could, but I figured that is impossible through free-hand style, so now I just follow the curvature.
Re: Spyderco Ultra Fine - problems with Vandium steels?
November 30, 2016 02:22AM
Erik,

In my experience, the Spyderco solid sintered ceramic stones are capable of abrading any steel, they are just extremely slow on highly wear resistant steels.

Using the stones dry, and with more force than the weight of the knife for a large volume of passes has a good chance of causing the stones to load with metal swarf and cut even slower, that plus the force used increases the chance of burnishing the apex which tends to weaken it by plastic deformation (that is, burnishing means the metal at the edge is being squashed flatter rather than abraded),and increase the chance of forming a burr since the stones are dirty and some force is being used.

My experience with these stones is that they should be cleaned with a scouring powder and scouring pad prior to each use, they should be used with a thin coat of mineral oil to prevent the metal swarf from sticking to the stone, and they should be used with less than the weight of the knife force. Used in this manner with some patience, they can and will eventually work.

That said, those stones are not really ideal for doing large amounts of grinding on highly wear resistant steels.
Re: Spyderco Ultra Fine - problems with Vandium steels?
November 30, 2016 04:14AM
I am literally triggered by that stone.

On a high vanadium steel, you may need to use a series of very muddy stones to work up the polish before finishing on the UF in order to minimize damage.

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Bill22252 on YouTube. "See you space cowboy"

Resident Emerson Fanboi

Folding knives are fun, fixed blades are important.
Re: Spyderco Ultra Fine - problems with Vandium steels?
November 30, 2016 04:43PM
Erik,

SD, likely hit on one of the major issues, there is a big grit jump in those stones and that very fine stone will do very little cutting thus it only is going to do well if :

-the edge before it is applied is already burr free and very sharp
-minimal abrasion is needed

It isn't as much the vanadium specifically that is causing the problem as much as it is just the nature of high vanadium steels to be very wear resistant and high carbide steels prone to being less than ideal in taking a high polish due to fracture at the apex. The best results I had in using that stone were exactly as Bill described using a muddy stone before the UF to make sure the apex was burr free and ready to take the final polish.

The best trick is to make sure you work just an apex/micro-bevel with the UF. If you try to work the entire edge it is much more difficult as it takes many more passes and you can end up creating a burr and/or just fatiguing the apex. If you want to see how easy it can be to use this stone, try something like this :

-recut the edge to 10 degrees
-set the edge with the medium, work the entire bevel
-use a muddy stone (2000 grit Aotoshi or similar, a King for example very inexpensive) to work the entire bevel
-apex at 15 degrees on the UF, very few passes, alternate sides
Re: Spyderco Ultra Fine - problems with Vandium steels?
January 02, 2017 06:25AM
Problem solved!
Solution: I ground a micro-bevel.

Before I wasn't doing any micro-bevel at all and was just grinding at the whole edge with these ceramics. That works with the low-grit abrasives and low-alloy steels, but with fine ceramics against vanadium, forget it. I am kicking myself for not doing micro-bevels sooner in my sharpening journey, they dramatically decrease the amount of work required.

Instead of raising the angle by 5 degrees or so from the primary bevel, I laid the knife blade on a surface and raised the blade to make a 40 degree angle to ensure I was hitting the apex, and then ground 10 pps on the medium ceramic and then 10-15 pps with the ultra fine, and it was very, very sharp in about 2 minutes. Then I lightly stropped it with a few passes on leather and that Japanese green compound sold on Amazon, and now I can shave hair without touching my skin. Interesting that I also get better stropping response with a micro-bevel.

I will now be doing micro-bevels on everything, forever. Thanks all for your feedback.