RSK Sharpening issue

Ok, mini RSK,M2 using a Sharpmaker at the 30 degree angle. All of a sudden I can't seem to get it shaving sharp. What am I doing wrong? Do I need to try the 40 degree for a while and then go back?

I don't have an M2 Ritter but it sounds like you need to resharpen the edge as opposed to touching it up. Did you use it a lot before putting it to the Sharpmaker? You may need the diamond stones. M2 is hard machine steel. If all else fails find a local knife shop to grind a new edge and touch it up with the Sharpmaker or send it to BM for "Life Sharp" service.

"send it to BM for "Life Sharp" service."

Ors,
Have you tried the sharpie marker on the edge to make sure you're using the correct angle?

No knife I own (none!) came from the factory with the edges ground at an accurate angle. Additionally, each knife's edges are not the same (i.e. one edge will be, say, 21 deg, and the other, say, 19 deg). I've had to regrind the edge on each one of them so that both sides are the same. I usually regrind at 12-1/2 or 15 degrees.

At 15 degrees, the Sharpmaker's 30 deg setting works well. At the final passes on the fine stones, I'll increase the angle by eye just a tad, and use very, very light strokes.

At 12-1/2 degrees, I have a 1/4" hardwood block that I set under one end of the Sharpmaker to increase the angle. I swap this block to the other end when I switch edges.

The sharpie marker will tell you how you're doing angle/edgewise.

I hope I didn;t overexplain this to an already experienced sharpener.... but it appears you're having trouble with the S30V. Diamonds are great, but you don;t need them for S30V...the Sharpmaker's ceramics will do fine.

Each to his own, but I don;t strop S30V. I leave it as it came from the fine white stones.

RAS has a pretty good idea....BM Lifesharp will take care of you....eventually. They can take several weeks to get your knife back to you. Plus, when it gets back, you'll use it and need to resharpen it soon enough. S30V is good but not invincible. So, I'd recommend pounding away at the Sharpmaker.

The thing I noticed is I can get good and fast at one or two knives. The others I fuss and fight with until I get them right. By that time, I'm not good at the original ones! I think I get familiar with the edges while I'm working them....each one is unique. Once I get them sharp, I've lost the feeling for the other blades. It never ends.

Keep trying Ors. Use the Sharpie marker. Increase the angle *just a tad* on your final passes on the white stones (corners, don;t use the flats) and use whisper-light pressure.

MY mistake. You have M2 not S30V. Same principal though. Use the Sharpie. I don;t own any M2 but from what I've read it will take a little longer on the ceramic rods. You might need diamonds later, but with a little work the ceramic will work.

Not my idea. billym mentioned it first in the thread, but it's a Benchmade so the policy applies. Sounds to me like he let the knife get to dull and it just needs a new edge. I'd use the Sharpmaker and not go for an acute edge. Making the edge too thin is the reason so many knives won't hold their edge. Do you really need it to shave with? I see so many guys who reprofile the edge so that they can shave their arms, but is that a realistic requirement for an EDC utility blade?

My apologies RAS... I didn't notice the quotation marks.

No, I don;t think you need a super fine edge. It's a personal preference. 15 degrees is 30 inclusive though.... 12-1/2 is 25. That's not too fine for an RSK. You (no, I) want it as sharp as I can get it, not necessarily a fine edge, just a very sharp one.

I think that Sharpmaker will do the job from 30 to 40 degrees, and several on either side of that.

I've got an old Tri-Hone that I used exclusively for years. It came with a 23 degree wedge which I suppose would give a 46 degree edge in addition to stock thickness. It's a robust edge and I've found it to be plenty sharp for any wilderness requirement. I've used that on a few of my folders and find them to be sharp enough for my needs. I just don't need to shave my arms.

Ors,
I've always found that the "Razors Edge" 'system' to give exceptional information regarding sharpening. Basically, after you've prepped the edge (getting the right 'relief') then as long as you keep the angle to less than or equal to 25 degrees, you can get a razors edge. To prep the edge, you have to grind down the area behind the edge so that it is (relatively) thin. If you get the book "The Razors Edge Guide to Sharpening", I think you will find it an excellent resource to your library.

CJ

I don't think I've let the edge dull much. Usually when I notice that it doesn't cut things with very little effort, I touch it up. I guess I'm just confused as to why all of a sudden I can't get it that sharp again.

And by the way...I use it to shave LEG hair

But seriously, I tried the Sharpie idea on an Emerson CQC7, and most of the marker is still there. The Sharpmaker seems to be dulling the edge there...not sharpening it.

I had looked at The Razor's Edge a long time ago...maybe it is time to invest in it. Speaking of which, I've been thinking of getting an Edge Pro sharpener too...but don't have the cash at the moment. Anyone have opinions on the Edge Pro?

I've hacked away on my Becker Necker with the Sharpmaker, and it doesn't seem to do much good. For those suggesting continuing with the Sharpmaker, should I keep alternating between the coarse and fine stones, or work with the coarse until the edge shapes up? Maybe I'll end up sending it in.

So for EDC utility blades, what's your test for judging if it's sharp enough?

Go coarse only until you reestablish the edge, then progress up to very fine. Since you need it to push cut, I'd take it as fine as the sharpening system you have allows.

I've been noodling this since I first read the post yesterday.

I agree that you should stick to course until you start feeling and edge. Alternating doesn't really help at all.

Is M2 steel really harder than the Sharpmaker's ceramic sticks? - or at least that close to the hardness of the sticks? I wouldn't think so.

Like Stretch suggested, rather than investing in another sharpening system maybe its time to invest in some diamond sticks for your Sharpmaker. I've used mine mostly when getting a fast edge on really dull stainless steel knives, but it might help you with the M2.

The thing is that the blade feels smooth as glass when it's going over the stones. So it doesn't feel like the stones are taking off any metal.

I was looking at another system to work on other things...axes, hachets, etc.

Maybe diamonds are a sharpeners best friend...

It could be your stones are bound up with metal and require reconditioning.

Pete

Best sharpener for any straight edged Benchmade is a Fallkniven D4 diamond ceramic sharpener. Followed up by a quick strop on a leather belt. I do all my knives with it.

Did a little demo today at work involving a Benchmade 721 (Mel Pardue design) Axis lock, 154CM steel and a sheet of A4 copier paper. Sliced it right across, edge to edge, Rambo fashion. Using fingertip pressure on the knife.

I was demonstrating that a properly prepared knife is a lot sharper, more durable and safer than the Stanley (craft) knives that most of them use.

If the knife ain't sharp the paper will buckle rather than cut.

I'm thinking of a couple of things:
- The Sharpmaker rods may be clogged. I wash them in the sink with warm water and Comet like the video suggests. I use a nylon scrub pad with the Comet on it. Inbetween cleanings I've been wiping them with Hoppes #9 and sometimes with Simple Green on a shop towel. The Hoppes leaves an odor (that happens to be ok by me but not by my wife). Another thing that works well is the Mr Clean sponges you can find at Home Depot.

- Your angle is possibly wrong....that's why the sharpie is recommended. When you're stroking the blade with light pressure, you should be able to feel the edge being ground against the stone. I'm guessing you're sharpening the shoulder of the edge...as opposed to the edge of the edge Improper angle or clogged stones. Or both.

Each to his own, but I still recommend sticking with the Sharpmaker (since it's a bird-in-hand right now). I don;t think it's the device that's failing you. Keep trying....clean stones and increase angle. Good luck

One more thing if it's ok. Until you get used to the edge on that knife, don;t use the flats of the rods. Use only the corners. Once you find the magic that THAT particular blade needs, you can try the flats. Me? I rarely use them.

I have the mini in m2 as well as the sharpmaker as well. The only angle I use is the 30 deg inclusive. I start with the edge of the fine and finish with the flats of the fine. The rods are harder than the steel and you can feel the change in surface texture as you go. I can keep the edge shaving sharp, but it will loose it with use. A good compromise for me as I only need to touch it up on occasion.

Different subject, has anyone else had a problem with the pivot screw getting too loose on the RSK mini? I have to tighten it every so often to take out the play in the blade. There is a sweet spot between the scales locked tight and the blade being able to fall open by gravity with the lock disengaged. Trying to hone in on it so I can loctite the screw.

Bill

You can get a shaving edge with almost any angle.

That is just edge refinment... And it will make the edge(whatever the angle) last longer.

He could convex it and make it last a long time too...

Re-watch the video that came with your sharpmaker...

The edge-pro is great...
I have the Pro edge-pro and love it.
Though I still perfer a convex edge for my heavy use knives, as it lasts forever and is EASY to keep sharp.

A MUCH cheaper alternative to the diamond sticks(man are they messy to clean up after...They leave COARSE metal/diamond dust EVERYWHERE!) is to wrap wet/dry sandpaper around the ceramic sticks and hold them on with the black metal paper clamps they have at the office supply stores.
Use the flat sides, as the corners will not last at all.
They will make the sharpmaker capable of reprofiling for less than $10.00 total... The dimond sticks cost me a fortune, and they are STILL not corse enough!!!
The wet/dry paper is FAST and you can get a new surface when you need it, and best of all, you can have eight or nine grits ready to use in a few seconds... I find it is MUCH faster to go through a lot of grits than just a few... The transition between course and fine takes forever because it is very hard to get the course scratches out with the fine grit(or stone).
If you use a lot of grits, you only need a few passes(less than 10 per side) per grit.

Use a pink perl eraser on them...

Or clean them in the sink with Comet.

Wet/dry sandpaper is a good recommendation indeed, it should work well with M2. I have some experience grinding M2 and similar grades HSS and it's not as difficult to do well as in the case of D2 or some very abrasion resistant stainless steels. I always strop all my blades, including HSS and stainless. I think it's well worth the extra couple of minutes to ensure a flawless edge.

However, I don't quite agree with the notion that just about any angle will produce a razor edge. Yes, you can put a secondary bevel on a blade at a pretty blunt angle and it will still shave hair. But it's going to be a poor performer at any sort of serious cutting. Straight razors are very thin and hollow ground for a reason. The same reason why the cheap thin blade on the SAK will outcut many far more expensive knives when sharpened properly. A thinner blade just cuts better.

That's why I'm not really a fan of secondary bevels on a knife. After repeated sharpening the actual angle of the edge will get wider and wider as you remove more metal from the bottom and move toward the spine where the blade gets ever thicker. That's particularly problematic with saber grind blades where the primary bevel is often pretty blunt to begin with.

The primary bevel is the angle of grind from the spine (or from a point below the spine) to the secondary bevel. This angle is about 7 degrees, give or take a few. Even Scandinavian grinds have a primary and secondary bevel. This is because they are ground at a slight angle from the spine down about halfway (not all of them of course), then there is a secondary flat grind to the edge. I suppose there could be a few exceptions if there are Scandi grinds out there that are flat-ground from the spine all the way to the edge. In that case, there is only one bevel.

The cutting edge of most knives is found in the secondary bevel, which is usually ground between 12(24) and 20(40) degrees.

A micro-bevel is actually the third bevel. It is ground a few degrees more obtuse than whatever the secondary bevel is ground at. While it's a personal choice, I like micro-bevels. The knife's life doesn;t end when, after repeated sharpening, the secondary bevel becomes more obtuse, because it never does if the knife is sharpened properly. When sharpening, the secondary bevel needs to be ground at each sharpening before finishing with the micro-bevel. So..... how could repeated sharpenings make the edge more obtuse than with or without a micro-bevel?? THink about this now. You have a 7degree primary bevel on a flat-ground blade. You grind the secondary bevel at, say, 15 degrees. Each time you sharpen, you keep grinding that bevel at 15 degrees, whether you grind a micro-bevel or not is irrelevant. At what point does 15 degrees get more obtuse than 15 degrees? Do you think you might hit the spine someday? I don;t.

The Edge Pro is a great device...I've seen my neighbor use his. It also costs a fortune. Ors has a Sharpmaker...it's like a bird-in-hand. It will sharpen ANY knife (except a ceramic blade) that he wants to sharpen. Don;t give up on it Ors, IT WILL SHARPEN your RSK.

Well... it's just semantics but I disagree. In a saber ground blade there is the flat and there is the bevel (or two). Even if the flat is inclined at a very small angle it's still not called a bevel, or at least I know of no serious knifemaker that would call it that way.

Sure, if your knife has a secondary bevel you may keep the angles consistent throughout by grinding both the primary and micro-bevel. You'll have to do that sooner or later to establish a proper blade geometry as it changes through periodical sharpening but it's not everyday practice. Again, I have yet to meet somebody who regularly sharpens his knives that way. Besides, grinding the primary bevel simply isn't practical in many cases if the blade has been blued or Parkerized (think Kabar). Those knives were meant to be sharpened only on the micro-bevel. If you grind the primary bevel as well you will remove the protective coating, which will look really bad and expose the steel to corrosion.

Anyway, I'm not saying micro-bevels are bad but you do have to maintain a proper blade geometry if you want your knives to cut well.

No. You *don;t grind the primary bevel*. That's not what I typed. You grind the secondary bevel (15 degrees or so...or any angle desired). That's the secondary bevel there....that's the one to grind. It will NOT change on you, even after grinding every day for the rest of your life, unless the sharpener (person sharpening the knife) changes the angle of the grind.

It isn;t complicated and the math is still the same.

You are correct that no one you know grinds the primary bevel. I agree. But, *everyone* you know grinds the secondary. Micro-bevels? Some do...some don't. The point I was trying to make, Tom, is that the obtuseness or acutness of the edge is not going to change as was inferred in an earlier post. It won't happen.

Looks like I didn't make myself clear enough. My point was, a lot of people *only* sharpen the micro-bevel on a knife and nothing else at all. Especially folks who use a sharpening jig like Lansky or Gatco. On blued or phosphate coated blades that's pretty much the only way to go unless you want to ruin the finish on the main bevel. Repeated sharpening of the micro-bevel alone is going to change blade geometry and you don't need to do a lot of math to figure that out.

P.S.: I'm afraid you have confused a couple of things about bevels and blade geometry. Check out these two links for a proper explanation:
http://www.ragweedforge.com/grind.html
http://en.wikipedia.org/wiki/Primary_grind

Tom: We got off topic and I'm more than partially to blame. Ors is trying to sharpen his RSK and I hope he succeeds. And I hope he uses that Sharpmaker that he already has.

The only point I was trying to make with you was:
You said the angle increases ("gets wider and wider") as you sharpen. I said it doesn't. That's the sum of it.

We agree. If you re-read this thread, you'll also agree no one made any mention of repeated sharpening of a micro-bevel.



No Tom. I didn;t confuse those things. Please re-read. I'm sure we'll end up agreeing and, if not, well then then we won;t.

Unfortunately yes, you have confused the flat and primary bevel plus a few other things, but they're not relevant here and I'm sorry we hijacked the thread.

The original post was about poor results using the Sharpmaker. One possible explanation (and a likely one) is that our forumite used the Sharpmaker only on the secondary/edge/micro-bevel (or however you wish to call it) instead of maintaining a proper geometry by grinding the main bevel as well. If that's the case it can easily explain why the knife is suddenly getting "dull" though the edge itself has been honed properly.

Note that I said "You can get a shaving edge with almost any angle.", not a razor edge.
Sharpness and cutting ability are two completely different things...

Examples:
Note...For all of these, I am assuming,
1. A complete penetration cut(where the blade is completely covered by the material being cut).
2. A push cut being done, as slicing is a COMPLEATLY different subject.

Cutting cheese:
Wire cheese cutter...
Cutting ability A
Sharpness F
Hair popping sharp 3/8" thick survival/combat knife...
Cutting ability F
Sharpness A-
Straight razor...
Cutting ability B-
Sharpness A+
Mora Knife with true single bevel edge...
Cutting ability B-
Sharpness A
Medium thick Convex edge...
Cutting Ability B
Sharpness A-


Cutting wood:
Wire cheese cutter...
Cutting ability F
Sharpness F
Hair popping sharp 3/8" thick survival/combat knife...
Cutting ability D
Sharpness A-
Straight razor...
Cutting ability C
Sharpness A+
Mora Knife with true single bevel edge...
Cutting ability A-
Sharpness A
Medium thick Convex edge...
Cutting Ability A-
Sharpness A-

Notice how the sharpness does not change with the material being cut.
The cutting ability changes dramatically though.
Now those were just averages...
The harder the cheese, the less well the wire cutter will work.
Cutting ability(once the SURFACE is broken by SHARPNESS), is almost completely determined by two things(or three, depending on how you count one of them)...
1. The smoothness of the area of the knife in contact with the material being cut(mostly the sides of the edge).
2. The Geometry of the blade, including the thickness and height of the blade.
If you include smoothness in with Geometry(as it is just the micro-geometry of the metal after all), you could say that it is almost ALL, the Geometry of the blade, that determines the cutting ability of a knife.
Every transition of a flat surface to another flat surface is like a wedge stopping the blade from penetrating.

The wire cheese cutter has almost no surface area, and, because the cheese requires almost no sharpness to penetrate the surface, it can cut VERY easily in the cheese, but cannot cut anything harder very well at all.

The hair popping sharp 3/8" thick survival/combat knife can penetrate the surface very well, but QUICKLY succumbs to the friction from the cheese, and from the wedging effect of trying to split, rather than cut that is prevalent in this cutting, because of the thickness of the blade. The later effect is what causes it to perform badly against the wood also.

The straight razor will go about half way into the cheese and then rapidly bog down, as it shares the problem that all concave ground blades do, of not working at all well in materials that are thick at all, because of the way the blade quickly gets thicker. It is only saved by the fact that it is SO thin, and it's height is so small that it produces very little wedging force, and what little it does produce will tend to make the material stay away from the surface of the blade, further reducing friction. In wood, the result is close to the same.

The Mora knife with true single bevel edge will tend to wedge and bind a bit in the cheese, but is thin and low enough in height to still go through reasonably well. In wood it will tend to have the same advantages and disadvantages. Though not the easiest to push through wood, this shape has special properties for woodworking tasks that make it one of the best for bushcraft

The medium thick Convex edge, will, because is is designed to have smooth contact along it's entire surface, tend to have the most friction of all, but will not bind as much. The sticker the substance cut the worse it will perform, but in most substances, it will bind the least, making it one of the best general purpose profiles there is. There can be wide variations in the performance do to small changes in the geometry of a convex edge that can make it much more suitable to cutting tasks. For example, a Fällkniven F1 performs very differently than a Bark River Highland Special, which is a very similar knife, and which both have convex edges.