Hello all,
Just curious if anyone has had much experience sharpening the VG 'super-steels' (their words not mine).
Over the weekend, I was asked to sharpen a couple of Shun kitchen blades.
I went with my usual DMT stones and a strop, but had a very difficult time getting the blades even to ~200 BESS.
Some parts seemed to take the edge and others didn't.
I'm sure it would have been better on a belt, but, I was home and all I had was the diamond stones.
Anyone know any tricks to get this steel into shape?
05-02-2018, 01:11 PM (This post was last modified: 05-03-2018, 01:15 AM by Jan.)
You are correct Mr. Wadebevan, it is not easy to sharpen blades made of VG10 steel. Some two years ago I have sharpen Japanese santoku knife made of VG10 steel on Tormek.
After sharpening I have inspected the edge with microscope with mag 500X and have found a wide canyon (left in the picture) and an isolated nick. The nick shows the brittle character of the VG10 steel.
The burr has been raised but I have probably not removed enough steel along the whole blade because the sharpening on Tormek was so slowly.
I need you to figure it out Wade. We used the SET on a brand new Shun VG10 and one of these days I'm going to have to sharpen it. Jan's picture is interesting and bears out what I've seen before with high HRC knives. It seems that these knives seem to chip, not where the metal is thinnest (apex) but further into the blade where the metal is thicker (and perhaps more brittle).
Yeah, I looked at the edge under magnification and saw quite a number of odd chips, grooves and dents.
They don't look like anything I've seen on other steels. Almost look like a chip followed by corrosion?
I was thinking of trying to sharpen it using a reverse stroke... with the edge instead of against it.
As I have very limited experience with doing so, I didn't try it, but I likely will.
It is a very strange steel for sure. Didn't seem very homogenous end to end.
05-02-2018, 03:39 PM (This post was last modified: 05-02-2018, 03:48 PM by Mark Reich.)
Hi Wade,
I've had a fair amount of experience with VG10, and it's been outstanding for me. It's easily one of my favorite modern stainless steels. It compares very well against other high quality, high carbon, non-powdered stainless steels like 154CM, AUS10, D2, 12c27, and the rare 440C with cobalt. VG10 actually has cobalt and tungsten, which are, generally speaking, my favorite alloys.
From what I gather, VG Max is just the powdered version. I guess VG Max could probably be considered a "New super steel" just because it's powdered, but I'm not finding the chemical composition. If VG Max has the addition of vanadium ubiquitous in powdered steel, plus the larger grain of powdered steels (powdered steels may be getting finer grained, but they started huge, and they're still only about size 5, which is not fine at all), I can see how it would be more difficult to sharpen. Unfortunately, you might as well get used to sharpening powdered steels, as the end of this tendency is disappointingly out of sight.
What type, what grit and what size DMTs are you using? What do you mean by, "it would have been better on a belt"? What type and what grit belts are you talking about? How are you finishing your edges?
I just sharpened my Al Mar SERE in VG10, finishing on 8µ PDP. Nothing special involved. It took about 4 minutes, and ended up at 115 ..... on my NEW PT50!!!
Wow, measuring just got WAY easier, and now I'm on a level field!! HUGE improvement!!
ps- I'll offer free sharpening to anyone who wants to send me their Shun knives. I want to see for myself what the problem is.
"ended up at 115 ..... on my NEW PT50!!! " and they say you can't teach an old dog new tricks! Glad you're happy with your new edge tester Mark. It won't be any more accurate than your KN100 but it sure is faster and more convenient to use.
Isn't it cool though? Wade says he's at 200 and Mark is 115 and all of us know exactly where each of your knives is at. BESS numbers just make me feel all warm and fuzzy. I say that if that 200 edge of Wade's has got some tooth on it that his friends will think that he's just about the best knife sharpener in all of Utah. My Shun Santoku was 170 out of the package so you're very close to sharpening as good as the guys at Shun can. Having said that I know that you are already hard at work in pursuit of Mark's 115. I think that someday the disease may find it's way into the American Psychiatric Handbook , Sharpaholicism...an incurable personality disorder.
@Mark, I use the 10 inch Course DMT primarily... I own the fine and extra fine, but rarely use them.
I believe the DMT Course is 325 mesh / 45 micron (according to their grit chart).
By better on a belt, I just think I would have had better results on a belt grinder with a 180-220 grit belt.. maybe not better, perhaps just easier/faster.
For finish, I used the strop that you produced for a few of us out here. 5 passes each side, then a looksie under the scope, then 5 more passes, and so on until the burr was removed (or at least not visible to me).
I don't usually look at edges under the scope because I can just get a feel for the burr. But this stuff just didn't give me the same feel, so I looked at the burr to figure out where it was at.
From the limited info I could find specific to VG-Max, it has a higher chromium content than the VG-10.
@Mike, yeah, Mark did throw the gauntlet on the floor on that 115 for sure!
I can usually get a kitchen knife to ~150-170, but I just couldn't get this there with my skills/setup with this steel.
But, Mark has raised the bar, and I must strive to jump over it
And yes, you may have started a new psych disorder... let me know if I need professional help at some point.
Wow wade, we were actually pretty close on grit, but I did have the advantage.
I used the 325 grit DMT for most sharpening for many years, so I know it well.
The 400 grit Atoma just leaves a lot more consistent scratch pattern, and crossing your scratch pattern when you finish makes a pretty big difference if you can do it accurately, and with the very least pressure. I admit it's taken me a lot of practice.
Instead of 16µ PDP, I finished on 8µ, which is another pretty big difference in refinement.
I think you did very well, Wade. 325 grit finished on 1k grit for a score of 200 is pretty salty.
It's great to hear you're having success with your leather hone. That made my day!
Incidentally, you can cross your scratch pattern on a leather hone too (always lightest pressure for finishing).
Wade,
I have not yet sharpened VG10 steel, but I had a similar problem with MAXAMET and S110V. I use a WE system with all the diamond grit paddles and three grades of diamond lapping film.
My "normal" reading for almost all knives I sharpen is below 150 and closer to 135-140. My Spyderco PM2 in S110V would not get below 150. Same thing with a friends MAXAMET blade. I've had my knife on the sharpener at least 6 times with the same result. I've analyzed and modified my technique - slower strokes with light pressure to no avail. At each grit change I run a sharpie right down the edge of the blade and use my scope to make sure I'm removing it all before I move to the next grit. These steels don't seem to provide much if any burr like the other pocket knives I've sharpened.
So, I did some web searching and found some other people who posted problems with sharpening these super steels. One thread caught my attention when it mentioned that diamond stones were the problem. They said that when they moved to finer grits they switched to Shapton/Chosera water stones and got a much better edge. Of course they didn't have an edge tester to quantify a "better" edge.
Long story short, I found that Bob at Oldawan had loaner Chosera 800/1000 stones for the WE. I used those and got my number down to 112. Just my experience YMMV
Just my experience YMMV